Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?
Hi John, Thanks for the response. Here is my 2 cents: Well, due to the level of difficulty in chip mounting, I would prefer to see a complete project. I.E., power supply for a single input of 12 volts and regulators the necessary chip values, proper input protection for the 10 MHz input level and single ended outputs of the appropriate levels (I am assuming more than 3 volts) or an amplifier stage for arriving at such. Equally have RF connectors (SMA would be good) on the board perhaps. Of course as cheap as possible, hi hi. A carrier board arrangement would be useless to me. My application would be to provide signals for things like my Quicksilver SDR receiver, among other uses. If you are interested, I can show you a nice little ABS (I think) box that has EMI built-in that I used for a project that should be more than large enough for your needs. Thanks for reading, 73BillWB6BNQ John Ackermann N8UR wrote: Hi Bill -- I should have been more clear: this design will be for a simple case: one reference clock input, four outputs. The chip can do all sorts of fancy tricks, but I'm looking for a source of four low jitter outputs derived from a 10 MHz external reference (not using crystal or on-board oscillator). Many of the pins are unused in that configuration. I'm not looking to make a universal carrier for the chip, but to meet what I suspect is a common time-nut/ham radio desire for a clean multi-channel synthesizer. On 01/25/2018 02:02 PM, wb6bnq wrote: Hi John, After looking at the data sheet, it seems way more involved then just making a carrier board for it. Besides the power supply requirements, various design selections would dictate different circuit layouts for different purposes. Even trying to do a general purpose application would possibly require having several different output configurations and possibly a couple of input configurations as well. That would imply a rather detailed PCB and that chip package style is a serious pain in the ass for [what amounts to] hobbyists. So it would seem the logical course would be to do serious design application and see if an in-house component mounting job would be feasible. I notice that the data sheet says the jitter specs are only best when using The internal crystal oscillator frequency between 48 and 54 MHz. It was unclear to me that the same would apply to using the non-crystal inputs. Perhaps you could indicate what you are attempting to do with it and how you are going to accomplish your goals ? 73....BillWB6BNQ John Ackermann N8UR wrote: After the recent discussion about Silicon Labs clock generators, I looked at their Si5340A part and think it will be useful for a ham radio project I'm working on. While it can do other things, for my use it would use a 10 MHz input clock and generate 4 independent outputs in the range of 100 kHz to 1028 MHz. Its jitter is <100fs, which translates to "not bad" phase noise. Here's the data sheet if you're interested: http://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf The challenge is that the chip is a 7x7 mm 44-QFN package and really wants to be put on a six-layer circuit board. That's doable, but challenging, for home assembly. Rather than designing the chip into a larger circuit board, I'm thinking of doing a small "carrier" board that would include just the chip and critical bypass caps and have headers to plug into the main board. Then, you could just drop the carrier into a project-specific board and not have to worry about the complex layout and mounting. I have a contract manufacturer who can build these up, if there's enough quantity to justify the setup cost. If you'd be interested acquiring in one or more of these, please drop me a line off-list (jra at febo dot com). I don't think this will be a TAPR project, but if there's enough interest to build 25 of these carriers, I can probably make that happen. And remember -- this is just the chip; you'll need to provide the rest of the circuit. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?
Hi John, After looking at the data sheet, it seems way more involved then just making a carrier board for it. Besides the power supply requirements, various design selections would dictate different circuit layouts for different purposes. Even trying to do a general purpose application would possibly require having several different output configurations and possibly a couple of input configurations as well. That would imply a rather detailed PCB and that chip package style is a serious pain in the ass for [what amounts to] hobbyists. So it would seem the logical course would be to do serious design application and see if an in-house component mounting job would be feasible. I notice that the data sheet says the jitter specs are only best when using The internal crystal oscillator frequency between 48 and 54 MHz. It was unclear to me that the same would apply to using the non-crystal inputs. Perhaps you could indicate what you are attempting to do with it and how you are going to accomplish your goals ? 73BillWB6BNQ John Ackermann N8UR wrote: After the recent discussion about Silicon Labs clock generators, I looked at their Si5340A part and think it will be useful for a ham radio project I'm working on. While it can do other things, for my use it would use a 10 MHz input clock and generate 4 independent outputs in the range of 100 kHz to 1028 MHz. Its jitter is <100fs, which translates to "not bad" phase noise. Here's the data sheet if you're interested: http://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf The challenge is that the chip is a 7x7 mm 44-QFN package and really wants to be put on a six-layer circuit board. That's doable, but challenging, for home assembly. Rather than designing the chip into a larger circuit board, I'm thinking of doing a small "carrier" board that would include just the chip and critical bypass caps and have headers to plug into the main board. Then, you could just drop the carrier into a project-specific board and not have to worry about the complex layout and mounting. I have a contract manufacturer who can build these up, if there's enough quantity to justify the setup cost. If you'd be interested acquiring in one or more of these, please drop me a line off-list (jra at febo dot com). I don't think this will be a TAPR project, but if there's enough interest to build 25 of these carriers, I can probably make that happen. And remember -- this is just the chip; you'll need to provide the rest of the circuit. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Charles Wenzel GPSDO
Chuck, It is an analog version of the BROOK SHERA approach from almost 20 years ago. BillWB6BNQ Chuck / Judy Burch wrote: I have been waiting for Charles Wenzel to get around to designing and building a GPSDO. Well, he has done it now and you can see it at <http://www.techlib.com/electronics/GPSstandard.htm>. Any thoughts on the design relative to more conventional ones?? Chuck Burch ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output
Hi Clint, Actually there are two versions of the 5680. The older version is exactly like the 5650 option 58 composition. The newer version has the DDS as part of the signal generation for the physics package. And it appears that they may be using an FPGA programmed as a divider to provide the output frequency. BillWB6BNQ Clint Jay wrote: Yes, in the 5650 there's only DDS on opt 58, in the 5680 there is one in the main loop too, my bad for not being precise/muddled. On 10 Jan 2017 01:43, "wb6bnq" wrote: HI Bob & Clint, If you look at the second message of this thread, I attached the manual that applies to Option 58. Look at PDF page # 16 and you will see that there is no DDS in the physics package. The DDS is only used down stream in some variations of the product such as the Option 58 being discussed. BillWB6BNQ Bob kb8tq wrote: Hi In most Rb’s (including the FE 56xx’s) the DDS is mixed with a fixed microwave frequency signal. The DDS only has to make up “part” of the total offset. You get roughly a three orders of magnitude improvement because of this. Rick has gone into all the gory details of why it gets done this way in talking about the 5071. It is the same thing on an Rb. So, your basic math is correct about a normal DDS. In this case you are in the PPT rather than PPB range due to the multiplication. Bob On Jan 9, 2017, at 10:40 AM, Scott Stobbe wrote: A 32-bit DDS synthesizing at 1/5 Fs, yields a tuning resolution of ~ 1 ppb. So, I would imagine a slightly lower frequency is programmed into the DDS and the c-field is trimmed to yield a higher precision. If the new synthesized tone you wish to generate is an integer number of DDS codes you could start by assuming the c-field is trimmed to be on frequency, but if the new tone is a fractional number of 32-bit DDS codes you will have to manually trim if you want higher precision. On Mon, Jan 9, 2017 at 4:48 AM, wb6bnq wrote: ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output
HI Bob & Clint, If you look at the second message of this thread, I attached the manual that applies to Option 58. Look at PDF page # 16 and you will see that there is no DDS in the physics package. The DDS is only used down stream in some variations of the product such as the Option 58 being discussed. BillWB6BNQ Bob kb8tq wrote: Hi In most Rb’s (including the FE 56xx’s) the DDS is mixed with a fixed microwave frequency signal. The DDS only has to make up “part” of the total offset. You get roughly a three orders of magnitude improvement because of this. Rick has gone into all the gory details of why it gets done this way in talking about the 5071. It is the same thing on an Rb. So, your basic math is correct about a normal DDS. In this case you are in the PPT rather than PPB range due to the multiplication. Bob On Jan 9, 2017, at 10:40 AM, Scott Stobbe wrote: A 32-bit DDS synthesizing at 1/5 Fs, yields a tuning resolution of ~ 1 ppb. So, I would imagine a slightly lower frequency is programmed into the DDS and the c-field is trimmed to yield a higher precision. If the new synthesized tone you wish to generate is an integer number of DDS codes you could start by assuming the c-field is trimmed to be on frequency, but if the new tone is a fractional number of 32-bit DDS codes you will have to manually trim if you want higher precision. On Mon, Jan 9, 2017 at 4:48 AM, wb6bnq wrote: ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output
Hi Matt,
Well, after rereading Mark’s paragraph in question, I think he did not
properly develop his complete thoughts. The first statement about the
Hydrogen Maser is absolute. The second statement is the one that is
really vague. The third statement is the clue taken with the fact that
the first sentence states the purpose of being used as a general purpose
programmable frequency synthesizer.
So the answer is leaving the C-field pot untouched and taking the
difference between the “R” value and the “needed” input frequency
associated with the current “F” value to produce the original output
frequency gives a correction term to be applied to the “R” value to
produce the value you use to come up with the new “F” value used for
determining the wanted output signal.
{After thought sentence} The above is not all that clear either, oh
well. Read on it becomes clearer.
So lets go through the process and see if I can do this without screwing
up. The formula for the DDS chip to produce a desired output for a
given system clock frequency is the following :
FTW (in decimal) = (Desired Output Frequency x 2^n) / SYSCLK
However, the need is to determine what the proper input frequency is to
produce the 8388608 Hz with the given “F” value as the FTW (Frequency
Tuning Word). So the formula is the following:
SYSCLK = (Desired Output Frequency x 2^n) / FTW (in decimal)
In your reported numbers this produces :
first 2^32 = 4,294,967,296 times desired output of 8,388,608 Hz =
36,028,797,018,963,968
SYSCLK = (Desired Output Frequency x 2^n) / FTW
(in decimal)
50,255,055.809934059845495428970822 Hz = 36,028,797,018,963,968 / 716918854
So the above 50 MHz number (SYSCLK) is the result of adjusting the
C-field so the unit is “ON” frequency for the expected 1 Hz output from
the factory. This is the SYSCLK value that should be used to find the
new “F” value for the DDS upon selecting a new output frequency such as
10 MHz (or as close as possible without touching the C-field) if that is
your wanted output value.
Actually, now that I have done the exercise, computing the delta between
the “R” value and the above 50 MHz makes no sense and serves no
purpose. I cannot stress enough. This is all predicated on not
touching the C-field adjustment and assuming the 1 Hz signal is
precisely on frequency.
This method does not give a lot of confidence as to preciseness. The
real value in these Rb units is they have a much lower drift rate than a
reasonably good quality Quartz oscillator. Typically less then parts in
10 to the minus 10th or minus 11th per month.
BillWB6BNQ
Mathias Weyland wrote:
On 2017-01-04 10:16, wb6bnq wrote:
Hello Bill
Thanks for re-iterating over this.
Yes, I do think the outer can covering is a MU-metal shield. The
bottom plate where the connector is located is not.
That is reassuring thank you!
I know the calculator that comes with Windows XP will produce the
correct mathematical results. I think the Windows version 7 does the
same. I do not have Windows 10 and therefore cannot address that
one, if there is one. Even EXCEL spreadsheet does not do the job
properly. So use caution with your calculations.
OK noted. The original calculations were done with a calculator that
was designed for high precision (in the floating point sense). I did
re-run the calculations in windows calculator for kicks, and the
result is different, although the difference is too small to have an
effect on the integer phase accumulator increment (fingers crossed!)
However, with all that said, it means nothing if you cannot properly
measure the final value against an external standard of greater
accuracy. Acquiring the equipment to do the external measurements is
where the real cost comes in.
Yes, I think that I am aware of that and I have the opportunity to
do that with somebody else's gear. I also understand that I'm supposed
to do that on a regular basis.
Hopefully the above helps to clear up your query ?
Yes most of it is clear, thank you. Unfortunately though my original
question, i.e. how to incorporate the reported R value into the
calculation, is still kind of open. I'm still convinced that what I
did, i.e. not taking the R number into account, is no worse than
using it. But this might be incorrect, and if it is I'd like to know
why.
Regards and thanks again
Matt
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Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output
Hello Mathias, I did mis-speak. You're correct that only 32 bits (8 hex digits) are used to program the DDS chip. As Mark points out they store a 64 bit number and only use 56 bits but he does not elaborate on what is done with the bits beyond 32. Also, after reviewing my comment on the “R” number, I see that I did not really convey what my mind was trying to compose. Let me try again and see if I can be clearer. The Rb physics package, itself, is an extremely narrow filter that, under certain conditions, is stable to some finite degree with an extremely small drift. One function that can modify the filter is a magnetic field. By shielding all external magnetic influences except for what is purposefully introduced, the finite frequency of this filter can be varied by a small amount. This is what the C-field adjustment is doing. Yes, I do think the outer can covering is a MU-metal shield. The bottom plate where the connector is located is not. A Rubidium frequency standard is a controllable crystal oscillator fed through the Rb filter with a feedback signal from the filter to keep the crystal oscillator centered on the Rb filter. By making very small changes to the Rb filter, the crystal oscillator frequency can be steered. Over the long term of many months the Rb filter is more stable than a crystal oscillator and thus becomes a higher level standard relative to a good crystal oscillator for the long term (months). In the scheme of things, the Rb filter is narrower than the crystal is and these adjustments are very small compared to the Rb frequency (6 GHz). So setting the C-field to minimum and adjusting the final output frequency with the DDS to the closest step just below the desired frequency and then adjusting the C-field, by external comparison, to the correct wanted frequency achieves the desired result. I know the calculator that comes with Windows XP will produce the correct mathematical results. I think the Windows version 7 does the same. I do not have Windows 10 and therefore cannot address that one, if there is one. Even EXCEL spreadsheet does not do the job properly. So use caution with your calculations. However, with all that said, it means nothing if you cannot properly measure the final value against an external standard of greater accuracy. Acquiring the equipment to do the external measurements is where the real cost comes in. At the minimum you will need a good “timing” GPSDO and I would highly recommend the Trimble Thunderbolt (properly set-up of course). The next item is a good time interval counter like a HP 5335 with GPIB capability. Add a GPIB controller to acquire the needed data, specifically one of these two https://www.sparkfun.com/search/results?term=gpib would be an excellent choice. With these three items you can make a computer version of a strip chart measuring the delta difference in frequence between the Thunderbolt and the Rb. Hopefully the above helps to clear up your query ? BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Problem with HP 83623A 20 GHz sweep generator stepping up/down 100 Hz when not wanted.
Dr. David Kirkby (Kirkby Microwave Ltd) wrote: snip .. The radio ham that noticed this step change in frequency is well used to listening on 10 GHz, and hearing beacons. So I think its reasonable to assume that the problem is not his end, but my end. Any thoughts, which do NOT include purchasing a second expensive 20 GHz signal generator. They are around $10,000 each, so a bit out of my price range. Dave Dave, I would not automatically assume that the problem is at your end of things. It could well be something has gone wrong at the other end. BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Temperature weirdness with Thunderbolt & Lady Heather 5
Hi Pete, Are you really at an altitude of 645 meters ? Also, it seems that your oscillator gain (currently at -5 Hz/v) may not be set right ? Have you checked the power supply voltages and observed them on an oscilloscope to see if they are relatively clean and free of spurious junk ? The available number of SATS is quite low and could be a matter of concern. BillWB6BNQ Pete Stephenson wrote: On 12/15/2016 7:45 PM, Charles Steinmetz wrote: Tom wrote: There's something very odd going on here, either with Pete's TBolt, and/or with Mark's Heather v5. 2) It also shows some truly erratic behavior the last day and a half, with multiple, massive, sudden temperature drops going down several degrees. I've never seen this. I think the more revealing trace is the DAC voltage. There are ~70mV plunges, to a dead quiet (at this scale), more negative value. 70mV is huge, corresponding to a -35e-9 frequency shift (350mHz). If the DAC voltage actually changed that much, it would pull the OCXO so far off frequency during these events that it would take much, much longer than shown (indeed, much longer than the width of these events) to re-stabilize. Yet we see clean jumps within seconds, and no settling. (Unfortunately, the Tbolt's estimation of frequency is not plotted on the posted screen shot.) Apologies, I did have the frequency plot turned off. I've taken some more screenshots with the frequency plot turned on. screenshot.png is a close-up of one of the odd spikes, while screenshot2.png took place ~10 minutes later (I just scrolled to the right). The small frequency jumps in screenshot2.png are due to satellites entering and leaving the field of view. Due to the setup of my apartment, the antenna location is decidedly sub-optimal and has a clear view only to the northwest. I find it hard to believe that LH does much processing of the reported DAC voltage, so I think it's safe to say (1) the LH plot shows accurately what the Tbolt is reporting (at least WRT the DAC voltage), and (2) the actual DAC voltage is not doing what the Tbolt is reporting. Looks like a sick Tbolt to me. Any idea what might be the issue? I can do SMT rework to replace a bad temperature sensor or other faulty chips, within reason (super-fine pitch stuff is a pain). Cheers! -Pete Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: ExpressPCB (cross-post from volts-nuts)
Dr. Dave, That is NOT true ! I use http://www.futurlec.com/PCBService.shtml to handle the my ExpressPCB actions. They are over in Asia somewhere and have been quite happy with their work. They are a bit cheaper than ExpressPCB themselves. They also will do other PCB programs and Gerber's as well. BillWB6BNQ Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 9 December 2016 at 19:58, BIll Ezell wrote: Sorry if I'm behind the times, just did a new project that required a pcb, and ExpressPCB is my go-to vendor for one-off boards. I just noticed they now provide the low-cost boards (fixed size, 3x5, quantity 3) that I've always ordered with silk screen and solder mask for $71. I got my latest boards that way and they're beautiful. No relationship to them, just a happy customer. You can still get the barebones boards for $51. You also lock yourself into one vendor. There's other free software, like Kicad, where you can export files that many PCB manufacturers use. So you avoid vendor lock-in. https://en.wikipedia.org/wiki/Vendor_lock-in If the company goes belly up, where are you going to get any more boards made, without starting from scratch? Anyway, it is a bit off topic. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Jim Miller simple GPSDO
Hi Bryan, No ! Assuming you mean R1/R2/C1/C2 of the Miller schematic, those values are already set for the comparison frequency (10KHz) of the PLL phase comparator (U2). BillWB6BNQ Bryan _ wrote: Hello: I have been following the Jim Miller simple GSDO build project at http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm I have a few OCXO's kicking around, but wondering what would the appropriate components be for for R1,R2, C1, C2 to provide the PLL filter. I assume the PLL filter needs to be designed to accommodate a specific oscillator specifications, or maybe it doesn't really matter and can use the default values in the schematic?. Was also considering using a picdiv instead of the 2- 74HC390, not sure if that would be an advantage or disadvantage in terms of operating performance? Cheers ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Working with SMT parts.
Hello Orin, Like I mentioned before http://www.futurlec.com/PCBService.shtml will accept the ExpressPCB program file and their prices are very reasonable compared to having the work done through ExpressPCB themselves. BillWB6BNQ Orin Eman wrote: On Fri, Aug 12, 2016 at 7:25 PM, Brooke Clarke wrote: Hi Chris: ExpressPCB has very easy to use free software for schematic capture (later used to check the board wiring) and software for board layout including making custom components if their library of stock components does not have what you need. The output file format is proprietary, which makes it interesting that Far Circuits can read it. I just have not wanted to go through learning curve for Gerber files and all the associated stuff (maybe drilling, silk screen, solder mask) which is very easy to do with ExpressPCB. I did my first 'CAD' PCB with EasyTrax... a DOS program. Must have been about 1998 as that's the copyright date I put on the board. Believe me, getting any of the current programs to produce gerber files is trivial compared to using EasyTrax and making it produce gerber files. In fact, I usually us itead.cc for small boards and they provide the script to produce gerber files from Eagle, which is what I currently use. I've also used OSH Park and you can simply send an Eagle board file to them; just as easy as using ExpressPCB without the expensive tie-in. I must admit ExpressPCB leaves me with a sour taste - many published projects seem to use them as I suppose the author liked the free software. But then everyone that uses the ExpressPCB files that the author supplies pays the ExpressPCB premium. $300 in one case and the boards weren't even flat! Orin. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Working with SMT parts.
Hi Didier, I use ExpressPCB as well, but I send the ExpressPCB file to a company called Futurlec ( http://www.futurlec.com/PCBService.shtml ). They have reasonable prices. Because it is overseas it takes about three weeks to get the product back. So far I have been very impressed with the product I recieved. I have even had notches done in the four corners to fit a plastic box that came out very well. Also, There is a person who started to write his own version of layout program based off of the ExpressPCB program called "Copper Connection." ( http://www.robotroom.com/CopperConnection/index.html ) It is a bit more involved than the ExpressPCB program and does have GERBER files as a selection. However he charges for the program but it seems the prices are reasonable ( http://www.robotroom.com/CopperConnection/Buy.html ). 73....BillWB6BNQ Didier Juges wrote: The way ExpressPCB works is that their free software produces boards in a proprietary format, and you have to pay to convert their design file to Gerber. Your mileage may vary but I found the combination of design tools learning curve, board quality and quick service to be worthwhile to me. I have tried Eagle twice and never could manage to build the models I needed. It may have been an issue of not finding the right tutorial but I have produced several ExpressPCB designs in less time than I have tried (unsuccessfully) to produce a single schematic in Eagle, let alone a PWB. Since it is a hobby that has become a business, time matters to me, design time and delivery. At that point, the cost of the Gerber becomes somewhat irrelevant. Note that you can make boards of any size in ExpressPCB. I am not advocating it is the best solution for everyone, I personally would like to be proficient with Eagle, but Express PCB works for me. Didier KO4BB On August 11, 2016 10:45:45 PM CDT, Chris Albertson wrote: This seems totally backwards. Typically a Gerber file is something you make yourself on your computer then send it in for a prototype. Seems odd to buy them. I checked ExpressPCB prices and they are very high. I can get PCBs made quickly in the US for $3 per square inch, shipping included with $9 minimum order. And you don't buy the Gerbers. I notice ExpressPCB offers free software. But it is totally non-standard and you can't use it for anything other then for their service. Most people needing free PCB software use Eagle, some use Kicad or some others. But Eagle seems to be kind of a universal standard. On Thu, Aug 11, 2016 at 8:55 AM, Didier Juges wrote: I concur. I have been using ExpressPCB extensively over the last 2 years with great satisfaction now that it is possible to get Gerber files from them. I typically use the mini board pro service (3 bare boards, 2 sided with solder mask and silk screen) for prototypes and then buy the Gerbers -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Temperature controlled TCVCXO
Hi Nathan, Let me state what Bob is driving at in a different way. Your biggest problem with a TCXO is the crystal. It is cut so that the slope, relative to temperature, has the shallowest curve around room temperature (between 20 to 25 degrees C). If you cool or heat it from that range the slope becomes more radical. The more radical the slope the greater the change in frequency for a given change in temperature. The exact opposite of what is trying to be achieved. This translates into having to have an extremely tightly controlled oven system in an attempt to overcome the radical slope. In addition you will also have to consider the elevated temperature effects on the other components. It is a never ending battle. BillWB6BNQ Bob Camp wrote: Hi Ok, with a TCXO you have a temperature sensor that tries to servo the crystal on to frequency. You also have a crystal with a temperature dependance. As you try to heat / cool the TCXO your thermal variation hits one before it hits the other. The net effect is that the ADEV is actually worse with a TCXO than with an un-compensated crystal. Consider that a good oven has variation in temperature on the order of micro C over a few seconds to tens of seconds. That’s what you are trying to “emulate”. The next issue is that the TCXO has a loop design oriented towards wide tune range. Things like varicap diodes have a much bigger impact on a TCXO loop than they do on a narrow tune range OCXO loop. That (and possibly a coil or two) are yet another source of thermally induced variation in the oscillator. Just like the temperature sensor, there is a delay in the temperature hitting them compared to other parts of the oscillator. Again, you get a degradation in ADEV over the bare TCXO crystal. Next up is the crystal it’s self. A TCXO crystal likely has a turn temperature that is optimized to match the compensation approach being used. In some cases there will not actually be a turn at all. Thus there is no temperature “zero slope” point to hit with your temperature controller. This means that rather than you now need much better temperature variation control on your system. Bottom line: A $10 eBay OCXO is likely to beat an ovenized or cooled TCXO. Bob On May 13, 2016, at 9:52 AM, Nathan Johnson wrote: Can you elaborate just a little bit on "poor"? Is that due to the "flat points" or desired temps always being elevated above most sane ambient temps? Or just that temp control via TEC isn't as precise? Nathan KK4REY Sent using CloudMagic Email [https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2] On Fri, May 13, 2016 at 06:37, Bob Camp wrote: Hi Yes, it can be done. The performance will be poor, but it will work. Bob On May 13, 2016, at 4:15 AM, David wrote: Has anybody tried using a thermoelectric cooler to maintain a TCVCXO at a constant temperature in lieu of using an OCXO? I was thinking about this after reading some application notes in connection with constant temperature control using TECs with bipolar drive. The power required would be pretty low so I think a linear control circuit could be used avoiding the noise problems associated with a switching controller. Temperature sensor placement would be a challenge. I suppose as part of an automated calibration, the temperature could be adjusted over a few degrees from ambient to find any flat spots in the oscillator's ppm/C curve. One place I have run across this application of TECs is with laser diodes where coherence length depends on very tight temperature control. Typical laser diodes without temperature control have a coherence length of millimeters making them useless in more demanding applications like interferometry. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What is "accuracy"? (newbie timenut, hi folks!)
Hello Belinda, First off there is no such thing as accuracy, in and of itself. I know many people on this list will call me on that, but accuracy requires a point of reference. With regard to frequency that reference point has been defined by some World committee as a certain number of oscillations in a Cesium atom controlled within a specific set of conditions. The 100 ppm statement is talking about a change in frequency due to temperature, The typical 100 ppm statement is saying for every change of 1 degree (usually "C") the oscillator (or other components such as resistors, capacitors, etc.) will shift in value by a worst case of 100 ppm (parts per million). This has nothing to do with accuracy except that it would not be considered accurate relative to a reference point. What it does address is specifically the stability, but is not the only condition affecting stability. With respect to accuracy and stability, they are not related. That is to say you could have extreme stability (say parts in 10 to the minus 21) and it could be way off from the recognized standard reference. In the other direction you could have something that is adjusted to be precisely in agreement with the reference standard but will only hold that value for a very brief period of time. The first case is a very good (and quite expensive) oscillator and the second example is a poor (and not expensive) oscillator. With regard to precision, the best example would be shooting at a target and how tight the grouping is maintained. The tighter the grouping the better the precision. You could have a tightly well defined small group of holes from the bullets but they could be anywhere on the paper target. The only time you have accuracy (with respect to the shooting) is if all the bullets were directly in the bulls eye (center of target). And if you can consisterntly repeat hitting just the bulls eye then you have stability. BillWB6BNQ BJ wrote: Hi Time Nuts, I'm fairly new to the fascinating world of time and frequency, so I apologise profusely in advance for my blatant ignorance. When I ask "what is accuracy" (in relation to oscillators), I am not asking for the textbook definition - I have already done extensive reading on accuracy, stability and precision and I think I understand the basics fairly well - although, after you read the rest of this, you may well (rightly) think I am deluding myself. It doesn't help matters when some textbooks, papers and web articles use the words precision, accuracy and uncertainty interchangeably. (Incidentally, examples of my light reading include the 'Vig tutorial' on oscillators, HP's Science of Timekeeping Application note, various NIST documents including the tutorial introduction on frequency standards and clocks, Michael Lombardi's chapter on Time and Frequency in the Mechatronics Handbook and many other documents including PTTI and other conference proceedings). Anyway, you can safely assume I understand the difference between accuracy and precision in the confused musings that follow below. What I am trying to understand is, what does it REALLY mean when the manufacturer's specs for a frequency standard or 'clock' claim a certain accuracy. For ease and argument's sake let us assume that the accuracy is given as 100 ppm or 1e-4 As per the textbook approach, I know I can therefore expect my 'clock' to have an error of up to 86400x1e-4= 8.64 s per day. But does that mean that, say, after one day I can be certain that my clock will be fast/slow by no more than 8.64 seconds or could it potentially be greater than that? In other words, is the accuracy a hard limit or is it a statistical quantity (so that there is a high probability that my clock will function this way, but that there is still a very small chance (say in the 3sigma range) that the error may be greater so that the clock may be fast/slow by, say, 10 seconds)? Is it something inherent, due to the nature of the type of oscillator (e.g. a characteristic of the crystal or atom, etc.) or does it vary so that it needs to be measured, and if so, how is that measurement made to produce the accuracy figure? Are environmental conditions taken into account when making these measurements (I am assuming so)? In other words, how is the accuracy of a clock determined? Note that I am conscious of the fact that I am being somewhat ambiguous with the definitions myself. It is my understanding that the accuracy (as given in an oscillator's specs) relates to frequency - i.e. how close the (measured?) frequency of the oscillator is to its nominal frequency - rather than time i.e. how well the clock keeps time in comparison to an official UTC source but I am assuming it is fair to say they are two sides of the same coin. Does accuracy also take stability into account (since, clearly, i
Re: [time-nuts] 1 PPS 50-ohm driver
Hi Douglas, Blowing up the picture shows some lettering in the white bar at the bottom of the display (fairly fuzzy). It looks like it is saying 2 volts for the signal with the scope set to 0.5 volts per division. BillWB6BNQ Douglas Bercich wrote: I was looking but can't find a V/div anywhere on that. Maybe my old eyes or not enough coffee. 500mV? On Apr 16, 2016, at 11:58 PM, Stewart Cobb wrote: Here's a scope photo from a PPS driver built exactly to the description in my earlier post. It's a 74ACT04 in a TSSOP package, with five parallel outputs driving five 220-ohm resistors (0402 SMT) to form a 50-ohm output. The photo shows 2 ns rise time for the leading edge of the pulse. The scope bandwidth is around 1 GHz, so this measurement is pushing its limits. The pulse looks fairly clean, but with a bit more care in layout and cabling, it might get even better. Cheers! --Stu ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] MTI 260-0624-D OCXO
Hi Mike, There are three possibilities in play. 1. The pot does set the EFC range OR 2. It adjusts the oven temperature. 3. In either case the adjustment range may be small enough that your current equipment resolution may not be able to see the change. If it were the EFC adjustment, I would think that should be see able. The oven set point circuitry may mask the pot change in that the pot's range may be just a small fraction of the total temperature adjustment. That is to say there may be fixed resistors in series with the pot that would have a bigger effect. The fixed values set it to near the turnover point and the pot's small value may have just enough range to make it just past the turnover point. My two cents, BillWB6BNQ time...@metachaos.net wrote: I have just about finished trashing this OCXO. I was able to run it outside of its case, and I have repaired the case, but I was unable to reinstall it into the case because I have to patch it on both the top and bottom. I could, perhaps, put it into a larger case and might do that later. For now, I will keep it as a potential future resource. The SC crystal is worth that much - they aren't cheap and nothing wrong with that. Also, just the bottom circuit board has problems, possibly another bad unit could be used for parts. That leaves one final question. The suggestion that the POT adjusts the temperature set point for the crystal sounds very reasonable. It clearly does not significantly affect the frequency. At least, not in the range that would allow for tuning the output frequency. However, the POT is clearly designed to be adjusted AFTER everything is assembled because it is intended to be adjusted through the hole in the case. That assumes some sort of feedback. What feedback? What can it affect on the available five pins that would let you know when the temperature is set correctly? If it is not for setting the temperature, and not for setting the frequency, what is it for? Perhaps output voltage level? I would have to get it working again, but I could test that. Any ideas? Mike ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] MTI 260-0624-D OCXO
Mike, Way more likely that "POT" set the temperature of the oven. BillWB6BNQ time...@metachaos.net wrote: Bob, The vendor has said that they did not want the unit back. So... I opened it up. Crudely, I admit. I learned a few things. I was concerned about the outer case heating up too much when I was trying to remove the solder. Turns out that the outer case doesn't touch anything except the pins, so it can get pretty hot without any damage. Unfortunately, I used a bit of brute force to remove the casing after scraping away as much of the solder as I could and after cracking the solder seal with a hammer and screw driver. Even using more heat, I'm not sure of the best way to remove the case. Neither solder wick nor a vacuum desoldering tool is likely to remove all of the solder between the top case and the bottom. Even so, I got the case off. Somewhat bent, even bent the bottom circuit board a bit. I discovered that there is a 2mm hole in the top that allows a variable resistor to be adjusted. You need a pretty long, small screwdriver / adjusting tool to do that, but that is probably for setting the center point. I would try to remove the solder rather than drilling, or drill upside down to prevent solder flakes from falling inside. Also, I found that the -D on my part number appears to correspond to the board revision, which is marked "Rev D". So the -C and -D parts probably have the same specifications. And, on the inside there is a marking "92.0" which I believe would be the set point for this specific crystal. So if I took the crystal out, I would know where to design the set point for a custom unit (currently beyond my skills, but who knows...). From there, I removed the bottom casing. That caused additional damage, some lifted traces and even one very small part (tiny, SMD, who knows?). But, I then soldered wires directly to the board, making patches for the lifted traces. I plugged it in. I turned it on. Success! I gave it 12v which should supply 2A, but it dropped the voltage down to just over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with nothing attached to the adjustment pin. After some time, the frequency stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached the adjustment pin to ground, there was no change. When I attached the adjustment pin to Vref (which is at 6.15v), the frequency dropped to 5.10Mhz. So apparently, these units adjust negatively. But also have a very wide adjustment range of 4Hz (8e-7). I am assuming that the adjustment range is 0..6v. I attached the adjustment pin to +10v and the frequency dropped another 3Hz for a 1.4e-6 adjustment range. I don't expect that this specific unit will be very useful given the damage that I caused opening it up. But, probably there were just bad connections internally, so if I were much more careful in the disassembly, I could probably have fixed it. Something to keep in mind for the next unit. I may be wrong for what the variable resistor does. Turning it made no difference in the frequency. I also suspect, but don't know that the difference from 5Mhz is due to the frequency counter being uncalibrated. It could also because I damaged the unit or just because it is very far off from where it should be. Still, I learned a lot, and well worth the time spent. Mike Hi The one advantage you have in testing a used OCXO is you have a pretty good idea of how you are going to use it. If phase noise does not matter to you … no need to test. I’d always check that it tunes on freq with reasonable EFC range left over. I’d also make sure that it warms up properly (oven works) and that it has a reasonable output. What goes on the list past that … it depends on what you need. The gear you have will check aging and get it set on frequency fine. It will check it for “wander” as your lab heats up and cools down. With a GPSDO and a simple phase lock, a DVM may be all you really need to do most of that. You will not have a proper ADEV, but you will know it works pretty well (or not ..). A lightbulb oven / bench / fridge /freezer proces can give you a wide range TC if you need it. If you do get into phase noise, a sound card system will get you going. For ADEV, the 10811’s tune far enough that a single mixer system with your 53131 will give you good data. Both of those will involve some building, but not a lot of money. There is one thing about the 10811’s: They are not sealed units. They tend to soak up humidity when stored in most parts of the country. You may want to run them for a month or three before doing any fancy testing. Bob On Feb 18, 2016, at 7:40 AM, Adrian Godwin wrote: I have a small collection of 10811 and similar oscillators here, collected fr
Re: [time-nuts] Valpey-Fisher VFT22H OCXO Output
Hi Logan, My guess is there is some second or third harmonic energy present. I have observed the very same thing on another oscillator. Look at it with a spectrum analyzer and see what kind of harmonic energy is there. BillWB6BNQ Logan Cummings wrote: Hi All, Curious what could give this waveform (attached) - I presume this is not correct output for this oscillator (surplus/salvage from Harris Constellation receiver). Frequency looks OK with +2V EFC but output looks like neither sine nor any CMOS I've seen into 10Mohm (first capture, scope probe alone) or 50ohm (50ohm term at SMA connector, probed by same scope probe) . What gives? If I open up the can, what am I looking to possibly replace/eliminate? How to open it? It's soldered shut (2x2in case). I need a good low-noise 100MHz sine wave for my application so I'm tempted to open this guy up and replace the output circuitry with something more suitable. Thanks in advance for any pointers/info on these units! -Logan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Newbie questions
Hi Mike, The element that you are missing is the impedance. When you look at the common formula it refers to a ratio of power or voltage and the impedance is left out with the understanding that the impedance is equal for each power or voltage in the ratio. The actual formula (for power) is DB = 10 X log10 ( E1^2 / R ) / ( E2^2 / R ). Hint Power P = E^2 / R. In the RF world that impedance is 50 Ohms and ZERO DBm(illiwatts) is ONE milliwatt into 50 Ohms which is 0.223606797749979 Vrms. In the audio world the reference impedance is 600 Ohms. So ZERO DBu is One milliwatt into 600 Ohms which is 0.7745966692414834 Vrms. More commonly referred to as 0.775 Vrms. As for your GPS questions, I will leave that up to others to answer. BillWB6BNQ time...@metachaos.net wrote: Hi, I am a newbie to this list. I have downloaded the archives and read about 5,000 of the past messages. I plan on building my own GPSDO, probably using a LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one affordably). I have a MTI 260 on order (although it could wind up being a 261 since they all appear to ship one or the other randomly). Currently, my resources include a DMM (well, a couple) and soldering / desoldering stations and quite a few tools. I also have an oscilloscope that I am currently repairing - a 400Mhz Tektronix 2465BCT analog scope. I am waiting on the final parts from Mouser. Once that is done I need to get it calibrated. All of that will probably take me another month. I also need to finish fixing my cassette deck - and then to finish writing a special recording program to use raw device drivers to get around the fact that Windows is not real time. I interrupted that project to work on the scope. In the meantime, I am reading the time-nuts messages (and lots of other things) to gather information and ideas about how I am going to do this and generally to learn more. So, I have some questions. Let me tell you a bit about me, so that you know the context and my limitations. I am a retired programmer. I wrote just about everything including device drivers, operating systems, utilities, various AI programs, telephone systems, compilers, encryption, web applications and much more. If I need to throw 50,000 LOC at a project, no problem. I have used many languages including quite a few different assembly languages (I have also written an assembler). I consider myself a mathematician / programmer, although I haven't really needed Calculus or Differential Equations for decades, so I am pretty rusty in that area. I do more work in formal logic than higher mathematics. But, I THINK like a mathematician. Formalism and abstraction come naturally to me. During my career I also helped to debug hardware during S-100 days. I have sporadically messed with electronics off and on, informally, with no education in the area. Now that I am retired (and have more time, but less money - it IS a zero sum game!), I am trying to learn more about electronics and start doing hardware projects. I have never been into model building or anything similar, so my construction skills are lacking. I understand a lot of things in theory, but practice still eludes me. For example, knowing a part exists or determining which of 10,000 apparently identical parts is the "right" choice. It can hours or even days to find the "right" connector. In many cases, the names or descriptions are completely meaningless. That all appears to be an experience related issue, so I will (hopefully) overcome that in time. I have no problem with soldering / desoldering, but I haven't designed or built my own PCB yet. I have designed / redesigned some minor circuits, especially on the power supply side. I can follow schematics reasonably well, but I am not comfortable with Eagle or other PCB layout programs. Every time I have tried one of those programs, half of the parts I needed were not available. I have started using TinyCAD which is much easier to use. So, I have a lot to learn. But, that is basically what I do, all day, every day. I'm the type of person that gets bored easily and quickly. As #5 said "more input, more input"! 6.02059991327962 Paradoxically, I have no interest in time. As in time of day, day of week, etc.. I have never had a job where I got to work on time. My philosophy has always been "go to bed when sleepy, get up when not". I was notorious in high school for only showing up on test day. But, I am interested in being able to timestamp events accurately and in measuring time (and other things). I am also interested in how a very accurate frequency source can be used in other applications and test instruments. That brings me to my desire to build a GPSDO and my questions. I understand the logarithmic scaling used for voltage and power. I even understand why voltage uses a multiplier of 20 and power a multiplier of 10.
Re: [time-nuts] eLORAN will be on the air
A whole year ago ? ? ? ? ? paul swed wrote: The Wildwood, NJ eLoran transmitter will be continuously broadcasting from 0900 (EST) on 05 January 2015 through 1500 (EST) on 15 January 2015. Wildwood will be broadcasting as 8970 Master and Secondary most of the time but occasionally may operate at other rates. Happy New Year everyone. Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Tuning a Trimble Thunderbolt
Hi Pete, I am a little confused. In your screen shot the overdetermined clock says you are at precisely 46.00 North by 7.0 East at 547 Meters. However, Google Earth shows that location at over 10 thousnad feet (>3100 meters) elevation in a remote part of the Switzerland mountains. Is that correct ? If so, how did you get right on the precise spot ? The likelyhood of having no decimal values in the Lat/Long is highly suspect to say the least. If those figures are still at those numbers, I would question the validity of the Thundeerbolt position and altitude. Also it shows you are only receiving two sats at the time of screen capature. Bill....WB6BNQ Pete Stephenson wrote: On Wed, Apr 22, 2015 at 1:47 PM, Bob Camp wrote: Hi Backing up a bit to “getting a TBolt running”. 1) instal Lady Heather and get it connected to the TBolt 2) does it fire up and find any sats? Yes. It had been working consistently for several days prior to my first message. 3) are the power supplies holding regulation? Yes. 4) nail down the antenna in the best fixed location you can find Done. 5) run the auto-calibration feature in LH Done. This changed the gain from -5.0Hz/V to -3.132Hz/V and changed the initial voltage to 0.347V. I switched the time constant and damping values back to their defaults of 100 seconds and 1.200, respectively. 6) run a 48 hour survey with LH and write the location to ee memory Done. The location matches the averaged location surveyed from my Motorola Oncore UT+ (the antenna for which was about 10cm away from that for the Tbolt, some no-name mushroom-type antenna) and a handheld Garmin eTrex 20 (with GPS+GLONASS+WAAS) within a few meters. It also matches with Google Maps. In the attached screenshot you can clearly see the field of view from the antenna's current location over the last ~20 hours. Interestingly, the Oncore antenna (a cheap patch antenna from eBay) seems to be causing some intermittent issues with the Tbolt: if the antennas are too close there appears to be some sort of interference emitted by the Oncore antenna that makes it difficult for the Tbolt to lock onto the GPS signal and the Tbolt goes into holdover. Oddly, this is not consistent: the Tbolt and Oncore had coexisted for a few days with no problems but today some of the problems started up again. The same issue occured if the Oncore antenna was too close to my Garmin GPS 18x LVC. I have since moved the Oncore antenna further away (it's now about 50cm) and signal reception for the Tbolt is much better. Weird, but distance seems to resolve the issue, so not really a problem anymore. 7) Then check the EFC voltage, it should be fairly close to 0V, and not over 2.5 If you are > 2.5, that’s probably a broken unit. Doesn't seem to be a problem. 8) Now start watching the EFC voltage for a few days and see that it’s leveling out and not spiking. Again spikes = something broke. See the attached screenshot. There's a few small EFC voltage spikes when the unit enters or leaves holdover, but otherwise it seems reasonably smooth in my (admittedly untrained) view. Until that’s all done, I would not dig to deep into the workings of the gizmo. It needs to be set up first. Other than the intermittent issues with the Oncore antenna, everything seems to be working reasonably well -- there's no obvious failures that I can spot. Cheers! -Pete Bob On Apr 21, 2015, at 4:30 AM, Pete Stephenson wrote: On Tue, Apr 21, 2015 at 4:25 AM, Charles Steinmetz wrote: Pete wrote: On a related note, is it possible to extract any data regarding the training from the unit? Not as far as the time-nuts community knows, no (other than looking at the DAC voltage and temperature reporting during holdover and attempting to reverse engineer the prediction algorithm by correlating those with the long-term DAC voltage -- good luck). Finishing my PhD is enough work already. I don't think I'll try reverse-engineering the prediction algorithm quite yet. Perhaps later in my Copious Free Time(tm)? Are the training parameters saved periodically to non-volatile memory, or are they purely stored in RAM and so will be lost if powered down? If the latter, does the RAM have any provisions for backup power I doubt it -- mine always act as if they are training from zero if they have been powered down. Because of the lack of precise retrace of quartz crystals, I don't think you'd want old (pre-power-down) data, anyway. Some crystals will even come up drifting in the opposite direction after being powered down, and they all take some time (days, at least) to settle down after any disturbance (including power interruptions, however brief). Ok. It'd be nice if there was some way to keep the crystal going through po
Re: [time-nuts] OXCO insulation
Hi Dave, It looks like some great stuff ! However, it is a material that has a big dust problem according to the manufacturer. Here is the web site listing of products : http://www.aerogel.com/products-and-solutions/all-insulation-products/ Read the SPACELOFT safety data sheet on the product at this URL : http://www.aerogel.com/_resources/common/userfiles/file/Data%20Sheets/Spaceloft_MSDS.pdf It is not dangerous, but can cause medical problems if mishandled. BillWB6BNQ Dave M wrote: Great find, Arthur. I had already convinced myself to use fiberglass insulation to reinsulate my OXCOs, but I'm going to order 2 or 3 sheets of this to play with. Thanks a bunch!! Dave M Arthur Dent wrote: If you check the popular auction site you can find several listing for Aspen Aerogel SPACELOFT Insulation. One listing has a 10"x14"x.2" piece for $7 including shipping and another listing has 481 rolls for $1.8 million, in case you have several ovens you need to re-insulate. ;-) http://www.ebay.com/itm/171328843398? -Arthur ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DDS on AD9852
Hi, I am not clear about the little sawtooth riding on the signal, but it looks like you are running out of headroom on the Ten-Tec preamp. The Ten-Tec preamp would not be my first choice for the job. One of the Minicircuits MMIC's would probably be a better choice depending upon your frequency range requirements. BillWB6BNQ d0ct0r wrote: Hello, I would like to ask some advise about the signal distortion I get from my DDS project. The T-Bolt GPSDO is in use as a REF signal source (10Mhz) for AD9858 DDS. This chip has two COS analog outputs which opposite to each other. I am using 20x reference multiplier in my project. And I am using Low Pass filter and RF amplifier connected to ONE of the COS output. The other output has no filter or op-amp on it. Attached is four files with OSC screen shots, where the signal which goes through the filter and amplifier somehow distorted. In contrary, the signal from another output (without filter and op-amp) has near perfect curve. I am using the same cable for connection to Oscilloscope.. And I set 5 Mhz output on DDS as an example. In this my project I am using Ten-Tec broadband pre-amp. The filter is standard Chebyshev Low Pass filter made by MINI-CIRCUITS. Model PLP-90 (81 Mhz). Here is the link to Ten-Tec http://www.tentec.com/products/Universal-Low%252dNoise-Broadband-DC-to-1-GHz-RF-Preamp-%252d-Model-1001.html Is it normal to have that kind of distortions for the signal, or something wrong with design ? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PRS-45A is alive!
Hi Bob, I think using a latching relay is a very good idea and prudent. Besides while it is reacquiring lock you would probably be busy resetting VCR's and so forth. BillWB6BNQ Bob Stewart wrote: Hi Pete, I don't have any way of knowing. I've asked the seller if he has a copy of the control software, and I don't like to go back with a bunch of petty questions like that. The next issue is adapting some serial port software i wrote to the protocol in the manual Magnus sent to see if I can pull the status codes out. That would probably tell me something. I have some tests I want to run immediately on my GPSDO and the KS to settle the question of which one can't keep time. After that, I'll power it down, lift its skirts and take some pics. It's pretty simple on the surface: a Cs Beam Tube, a main board, a microwave package with MTI 5Mhz OCXO, and the HV and LV power supplies. I don't intend to keep this thing running 24/7, but I have a question: Here in Houston, we have the occasional large thunderstorm and resulting short power outages. So, should I put a latching relay in the power stream to keep it off if I lose power? The budget is now officially busted, and a UPS is not going to happen for awhile. Santa's sleigh is now officially out of gas. Bob From: Pete Lancashire To: Bob Stewart ; Discussion of precise time and frequency measurement Sent: Monday, December 8, 2014 11:46 PM Subject: Re: [time-nuts] PRS-45A is alive! Love to have known how long it was off, and how much of that 16 minutes was getting the tube degassed. -pete On Mon, Dec 8, 2014 at 7:11 PM, Bob Stewart wrote: Well, it's alive, and I even have 10MHz coming from it. It took about 16 minutes to go to lock. Is that good, or doesn't matter? Now I've got to put together a serial cable and see if I can talk to it and find out how it thinks it's doing. But, this is good! www.evoria.net/AE6RV/PRS-45A/2014-12-08%2020.51.33.jpg Hope you enjoy the wall decorations. =) Bob - AE6RV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 5 to 10 MHz Quad Driven Mixer doubler article
Hi John, I would be interested in your article. May I suggest that if you do not have a means of putting it "ALL" into one PDF, let me know as I have scanning ability as well as publishing into the PDF format. That way it could be put on to a server that KO4BB maintains foir all the Timenuts list of manuals and other papers etc.. 73....BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10MHz Rubidium reference source for frequency counter
Hello Karen, I think you are confusing and/or mixing the terms "stability" and "accuracy" with respect to your project. It all depends upon your measurement period and the property being measured. A GPSDO will never beat a truly, very high quality OCXO on a short term basis in the stability department. For that matter most Rubidium's that you find on auction sites won't either. Accuracy, on the other hand, is another matter. A good and properly setup GPSDO will provide long term accuracy (years) with a Rubidium (months), calibrated, in second place and the very high quality OCXO (up to days) is last, again, with respect to accuracy. BillWB6BNQ Karen Tadevosyan wrote: Many thanks for all your recommendations. Let me provide more details for understanding of my task. I am playing with a GPSDO project on base of uBlox NEO-7M (http://www.ra3apw.ru/ublox-neo-7m-ocxo-gpsdo/) - sorry, text in Russian. One of the main step – ADEV measurement of a developed GPSDO. My ADEV measure stand consists of a frequency counter Pendulum CNT-91 with TimeBase option 19 + GPIB interface + KE5FX TimeLab software (TNX again John). As option for CNT-91’s reference source I can use a homemade GPSDO on base of G3RUH design. IMHO, in this condition a frequency stability of my GPSDO project should be higher than a stability of CNT-91’s reference OCXO. Taking into account that rubidium source has a better short range stability than OCXO or GPSDO I hope to find an external rubidium as 10 MHz reference source instead of internal OCXO of counter. If my reasoning is not right could you please correct them as I am not an expert in this area. Karen, ra3apw Date: Sun, 26 Oct 2014 14:45:00 -0700 From: Brooke Clarke Hi Karen: The ones you mention are all stand alone Rb oscillators that need to be calibrated to set their frequency. This was the historical way that crystal oscillators were calibrated every year or so. The great advantage of Rb over crystal oscillators is that their drift is specified in months instead of days. A much better - more modern idea - is the GPS Disciplined Oscillator (GPSDO). It keeps the oscillator "calibrated" in real time. A popular crystal based GPSDO is the Trimble ThunderBolt: http://www.prc68.com/I/ThunderBolt.shtml Another crystal based GPSDO is the HP Z3805: http://www.prc68.com/I/Z3805A.html There are many more commercial GPSDOs and this list has discussions that show they can be a do it yourself project for under maybe $10, but require a number of sophisticated skills. I have the just released LTE-Lite GPSDO Evaluation Kit with 10MHz TCXO on order. Seems to offer good performance for the dollar. http://www.ebay.com/itm/171504585820 The only advantage of a Rb GPSDO over a crystal GPSDO is for the case where the GPS updating has not happened for some time. This might be due to a power failure lasting some days or that the oscillator will be used where there's no GPS access and it only gets "calibrated" then used much later. The Stanford Research PRS-10 Rb oscillator can be used stand alone where it time stamps an external 1 Pulse Per Second input, or as part of a GPSDO where an external GPS receiver supplies it with a 1 PPS input. http://www.prc68.com/I/PRS10.shtml The Thunderbolt can be custom modified to drive an external Rb oscillator, like the ones you mentioned, but that requires some technical sophistication. Note the ThunderBolt and Z3805 are complete GPSDOs in a box, just connect power and a GPS antenna. The PRS-10 requires an external GPS receiver and antenna. A a practical matter that means it's more work to maintain the PRS-10 because there's more opportunity for problems like disconnecting a cable. PS Stanford Research offered a version of their SR620 Time Interval counter that included a Rb oscillator (not a GPSDO) that some government agencies purchased, but for normal use you really don't need a Rb oscillator, so the CNT-91R appears to be a similar way so sell it to a government with a lot of money to spare. So don't feel pressured to use an Rb oscillator. http://www.prc68.com/I/TandFTE.shtml#SR620 Mail_Attachment -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Yokogawa TA320 Time Interval Analyzer
Dave, Should have included the main page for that instrument. Here it is: http://tmi.yokogawa.com/us/discontinued-products/other-test-measurement-instruments/time-interval-analyzers/ta320-time-interval-analyzer/ BillWB6BNQ Dr. David Kirkby (Kirkby Microwave Ltd) wrote: I see this on eBay http://m.ebay.com/itm/220505574616 Note that the seller has misspelled the manufacturers name. Has anyone used one? I have never even heard of this manufacturer - I guess it is Chinese. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Yokogawa TA320 Time Interval Analyzer
Hi Dave, Here is a link to the manual for that unit. http://tmi.yokogawa.com/files/uploaded/ta320spec.pdf BillWB6BNQ Dr. David Kirkby (Kirkby Microwave Ltd) wrote: I see this on eBay http://m.ebay.com/itm/220505574616 Note that the seller has misspelled the manufacturers name. Has anyone used one? I have never even heard of this manufacturer - I guess it is Chinese. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DIY FE-5680A lobotomy (disable temp compensation)
Hi Scott, I reviewed the material at the N5TNL site and it leaves me wondering. There are at least three different and separate temperature controlling areas inside the FEI-5680. One of which has cannot be messed with due to the fact that it is inherent in its design. That would be the posistor (i.e., a PTC resistor) that is attached to the 60 MHz crystal that acts as a general heater. The other two locations are on the physics package itself. One for the lamp area and the other is for the cavity chamber. SO. The lamp area, I surmise is rather simple as it does not require tight temperature control like the cavity chamber area would need. The lamp area just needs a temperature to change and maintain the Rb into a gas form. The cavity chamber area is way more sensitive to temperature as it affects the pressure, frequency and stability of the Rb in the cavity. I suspect that the control mechanism for this area to be more complicated. The block diagram, while pretty general in nature, does show that the system (i.e., internal computer) has an A/D monitoring 4 inputs. Three of the A/D channels are observing "system data" and the fourth is temperature. What it does not tell us is what temperature or system data it is monitoring. SO... Here is the rub, the only temperature that is truly critical is the cavity temperature. BUT, the system computer does not really control that temperature, except possibly monitor it, as indicated on the block diagram. Thus the real question is, is that the temperature being referred to in the monitoring process ? In other words have you traced out the connections to see what is driving the pin you think is the temperature input ? I would think that the temperature reading would have a steadily climbing curve from the application of power to some steady state (relative) value. However, the curve that you selected as temperature seems to rise and become steady (relative) some period of time after application of power and seems associated with the unit going into a lock condition. OR, so you indicate on some of your graphs. The next big question is have you monitored the frequency and its stability, externally, to observe what effects are taking place when you disable this input to the A/D ? I realize Bert is trying to take FEI to a tighter level, but I wonder if it would be better to add thermal mass to buffer external ambient changes rather than screw with the internal control mechanisms. Particularly seeing as how we have no knowledge of the what the internal firmware is doing. By thermal mass I mean on all sides of the unit. The only way to really achieve that would be make a stirred oil bath container with the FEI suspended in the center of said bath. That sounds complicated and messy but may be easier than it appears. An appropriate container would be: http://www.worldkitchen.com/en/snapware-food-storage/1098437.html It is made out of polypropylene and can handle at least 130 degrees "C" and it holds just under two and half gallons of oil. Light mineral oil runs around $15 a gallon, so two gallons would be the right amount leaving a little room at the top. Wicking is a problem with wires and cables but using connectors attached to the lid solves that problem by breaking the wicking surface. The final question is how much, if any, external oil cooling would be necessary. That would have to be experimentally determined. The mineral oil, by the way, has a higher flash point then the container and is electrically NON-conductive. Food for thought, BillWB6BNQ Scott Newell wrote: Bert asked me to send an update on the FE-5680 tempco mod progress. It appears that the FE-5680A temperature signal (or maybe it's really a current sense signal?) can be disabled by removing a single 10k 0805 surface mount resistor. Using Elio Corbolante's terrific high-res scans, I've noted the resistor location: http://www.n5tnl.com/time/fe-5680a/lobotomy.png Why would you want to disable temperature compensation? As we've seen, the unit's firmware will adjust the DDS frequency as the temperature signal changes. If you're using the '5680 inside a control loop, it's likely to conflict. By removing the resistor, that channel of the 12 bit ADC will be tied to ground through an existing 2.21k resistor. The unit will see a constant 0 counts from the ADC and assume it's really cold. I modified one unit and monitored it for a few hours over a range of temps, running it nice and hot with no heatsink, then blasting it with a fan and placing it on an ice-cold heatsink. I observed no change in the DDS tuning words. It's a really easy mod--remove four screws, set aside the insulator sheet, and apply your hot leucotome/soldering iron. I've also found a simple mod to replace the temperature sig
Re: [time-nuts] FE5680 GPS Disciplined Controller
Hi Charles, NO, not easily. ! What we do know is that the rash of Rb's sold in the last two or three years with the label tag P/N : 217400-30352-1 are in fact the newer digitally controlled versions. Mainly you would need to compare pictures from the two versions which are available on the internet. For the newer digital version you can see pictures at the following site : https://plus.google.com/photos/109928236040342205185/albums/5680473650837554113/5685636673930493138#photos/109928236040342205185/albums/5680473650837554113 At the moment I do not recall where the older model is. But as I recall it was covered in a couple of PDF files by people who were showing how to connect and other such data about the older version. BillWB6BNQ Charles Steinmetz wrote: Bill wrote: There are two types of FE5680's. The older style used an ANALOG approach to controlling the Rb. The newer version changed the circuitry so that frequency control was done with a DDS device by means of sending a digital word to the DDS and thus changes frequency. The digital version does not permit any ANALOG control. Instructions for determining which version one has would make it easier for potential users to decide if they want a controller. Preferably, without opening it up or turning it on, if that is possible. Can you tell by the label, for example? Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE5680 GPS Disciplined Controller
Hi Dave, The short answer is NO ! There are two types of FE5680's. The older style used an ANALOG approach to controlling the Rb. The newer version changed the circuitry so that frequency control was done with a DDS device by means of sending a digital word to the DDS and thus changes frequency. The digital version does not permit any ANALOG control. Bert's board is for the newer style DIGITAL version. BillWB6BNQ Dave Brown wrote: Hi Bert Will this work with all 5680s? I understood (but may be wrong) that there are several versions of the 5680. I guess if the serial commands are the same for all models then all should be well. DaveB NZ - Original Message - From: To: Sent: Thursday, June 19, 2014 12:51 PM Subject: [time-nuts] FE5680 GPS Disciplined Controller FE5680 GPS Disciplined Controller schematic by request ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Is it Hz or MHz ?
Hi Tom, My experience is the manufacturer's, of hp or fluke quality, reported error band (their spec sheet) is the worst case (or at least 3 sigma) provided that the device is operated according to the recommended environment, etc. Nonetheless, my statement you quoted is still accurate as to the purpose of the specification. Although I probably should have qualified a bit more. It goes without saying that one should be careful when it comes to specmanship no matter who it is. BillWB6BNQ Tom Van Baak wrote: The value of 5E^-11 refers to the resolution that the precision can be relied upon after taking into account all the factors that influence it. It means that there is an error that can be as much as +/-5 parts per e^-11. No, it can be way more. A 5e-11 spec value is likely just RMS, or 1-sigma. Actual measurements will show significantly larger 2-sigma, 3-sigma, etc. value. Your "as much as" wording sounds more like a 6-sigma, or peak-to-peak spec. One must be very careful to match the measurement used to make the spec with how the device is intended to be used. For example, Magnus will likely tell us about MTIE, which is a perfect-storm, worst-case time error spec. It's very different from rough 1-sigma specs we usually talk about. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Is it Hz or MHz ?
Hi Kit, The value of 5E^-11 refers to the resolution that the precision can be relied upon after taking into account all the factors that influence it. It means that there is an error that can be as much as +/-5 parts per e^-11. At 10 MHz that is +/- 0.0005 Hertz error. At 5 MHz that is +/-0.00025 Hertz error. At 1 MHz it is +/-0.5 Hertz error. And, finally, at 1 Hertz it is +/-0.005 Hertz error. BillWB6BNQ Kit Scally wrote: Team Nutters, GPSDO's are often specified for stability as so many parts per x. Using a Symmetricom 8040C as an example, this has a quoted accuracy of typically 5E^-11 at shipment. Ageing (monthly and yearly) and ADEV stability rates for 1, 10 & 100 seconds are also given. This particular device as 1, 5 and 10 MHz outputs. The question - is this "accuracy" with respect to 1Hz - or 10MHz ? If the latter, then the accuracy figures quoted needs to be modified by 10^6 (Hz to MHz) to get a feel for the actual frequency changes at 10MHz. Glossies of many GPSDO manufacturers seem deathly silent on this point, so clearly, "something is assumed". I have seen an oscillator comparison chart by Meinberg (a German company) that in their comparison chart, the accuracy references need scaling to relate to 1Hz. Appreciate some advice and/or direction on this before madness overtakes me ! Kit Canberra Australia ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PRS10 rubidium on eBay
Corby, It would be nice to have included the eBay item number. BillWB6BNQ cdel...@juno.com wrote: Hi, I'm selling a nice PRS10 on eBay if anyone is interested. With manual and schematics. Works great! Cheers, Corby Dawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 74HCT9046A Max. Operating Frequency
Hi Samuel, I have yet to see where you answered what your reference frequency is for the PLL ? ? ? ? If you are locking a 24.576 MHz oscillator to a common house standard like, for example, 10 MHz then you are going to have a comparison frequency at 16 KHz. The reason is Phase Detector #2 has a max frequency of around 4 MHz so when you get done looking for an integer relationship it is going to be at 16 KHz. If you are trying to lock 48 KHz to 10 MHz, it will be the same thing. Please tell us what reference frequency you are using ? BillWB6BNQ sg sg wrote: Running my PLL design routine again for 48 kHz I realize that this is in fact very advantageous--it greatly reduces the required capacitor size in the loop filter. So dividers are clearly the way to go. Samuel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 74HCT9046A Max. Operating Frequency
Hello Samuel, Well, I just got done designing and building the very same thing. If I recall correctly it is the same as the HC4046 which is 4 MHz. The 9046 VCO will only go up to 20 MHz absolute maximum. So you will need an external oscillator and dividers. BillWB6BNQ sg sg wrote: Hi, I'm about to implement a PLL for a 24.576 MHz VCXO using the phase-frequency detector (PC2) of the NXP 74HCT9046A. From the datasheet (www.nxp.com/documents/data_sheet/74HCT9046A.pdf) it is not clear to me what the maximum operating frequency for this phase detector is--from the enable and disable times (page 20 and figure 19) I presume 24.576 MHz is too much. So I probably need to add dividers at the inputs. Can someone advise me on the choice of division ratio? Thanks for your time, Samuel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Another "atomic" clock question
Bob, I am curious, a week or so ago I sent you an email that gave links to some publications that would serve you very well in helping you to achieve your goals. Did you ever get that email and look at the linked PDF files ? ? ? ? BillWB6BNQ Bob Albert wrote: Chris, Okay you want numbers. Well, I think 10 ppb or thereabouts should do it. Somewhere there is a discontinuity in accuracy plotted against cost and I don't want to cross that barrier just yet. If I can get 1 ppb without a big increase in cost, I'll take that. My need for this is nonexistent. I am only interested in doing it for the fun of seeing all zeros on the counter and having it give me that repeatedly. The pleasure of knowing I am as close as the equipment is capable is what I seek. I'm sure many time nuts feel the same. I am not interested in offering a calibration service or tracking spacecraft or measuring the diameter of the moon. How do I get accurate frequency from GPS? I have the same fetish regarding components, resistors and capacitors and inductors. I have lots of good meters but am always looking for a better one. I am trying to get six useful digits of voltage and resistance measurement and eventually want to do it with current as well. Not so sure about temperature, mass, and force. Once I get where I want to be, I'll probably go into basket weaving. Bob On Sunday, March 2, 2014 5:46 AM, Chris Albertson wrote: On Sat, Mar 1, 2014 at 8:05 PM, Bob Albert wrote: Paul, as I said I just want to know how close my crystals are and be able to adjust them as well as they can be. Don't say "as well as can be" that can get expensive and time consuming. You need to use numbers. Say "and be able to adjust them at the 1E-8 level." Then you will get advice to just use WWV. But what if you need 10,000 times better? Then use GPS After that it starts getting harder but you still are not up to "as well as they can be." I admit to a few years ago using a 50 cent TTL can oscillator as my "lab standard" The part was salvage from some junk and was good to about 5 digits accuracy. It worked actually better than I needed. My RF signal generator was from the 1960's with a hand turned dial to adjust the frequency. The TTL can let me calibrate the dial. I probably will never go rubidium (note that I qualified that) but still somewhere one has to decide where to set the frequency. I did WWV at 20 MHz for a beat of somewhat slower than one per second. I know the phase changes but probably not much in a few minutes, as the path length doesn't vary very quickly. And I don't need phase lock to them anyway. In the old days they had 25 MHz and even 30 MHz for a slight improvement in settability if not stability. Bob On Saturday, March 1, 2014 7:38 PM, Hal Murray wrote: I am trying to understand how this is done. Should I ever get a rubidium standard, I'd want to check its calibration, and that's not a trivial exercise. If you assume your rubidium is stable, then it's pretty easy to check and/or calibrate. The trick is that you need someplace to stand. A PC running ntp is good long term. There is a tradeoff between good and long. Good is ambiguous, but both how-good is your PC clock and how good/accurate a measurement do you want are appropriate. Probably the simplest way is to get one of tvb's preprogrammed PICs. http://www.leapsecond.com/pic/picdiv.htm http://www.leapsecond.com/pic/picpet.htm One approach is to use a picDIV to make a PPS and then monitor that. If you have Linux, you can feed the PPS to a serial port. My hack for counting 60Hz will work fine at 1 Hz. http://www.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz.py Another approach is to use a picPET and connect a modem control signal from the monitoring PC to the Event input on the picPET. Then the data collection program grabs the time, flaps a modem control signal, grabs the time again, then grabs the text from the picPET and logs everything. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New WWVB modulation format receivers (NOT)
Hi Bob, Here are a couple of HP Appnotes, in PDF form, that will get you started in your quest. Some of the references to standard frequency transmissions may be somewhat outdated but the overall data is still valid. The first one is the original publication done in the early 1960's and the next two are a rewrite done in the 1970's. http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52_Frequency_and_Time_Standards_5989-6171EN.pdf http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-1_Frequency_and_Time_Standards_5989-6183EN.pdf http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-2_Frequency_and_Time_Standards_5989-6247EN.pdf http://www.ko4bb.com/Manuals/05)_GPS_Timing/The_Science_Of_Timekeeping.pdf And finally, here is an appnote about counters, generally, that is worth reading http://www.ko4bb.com/Manuals/HP_Agilent/HP_AN200_frequency_counters_1997.pdf There are plenty of other publications, but no need to overload you too early in the game. The stuff above will give you a basic understanding of the fundementals of which your questions to this list are centered omn. 73....BillWB6BNQ Bob Albert wrote: My TS-940S acts as though it receives okay at 60 kHz. Not great sensitivity but it does receive. Most HP GPS receivers are expensive ($400?). I was hoping to get some results with what I have, although I'm willing to cobble up some circuitry. I assume if I can receive the signal, I can figure out how to decode it and/or use it as is. How does one use a 1 pps signal to get precise frequency measurement? Maybe use it as a time base for a counter? My counter has 1 pps as well as 0.1 pps for 10-second count. I would assume signal fading would cause some timing uncertainty due to finite rise and fall time. And at 60 kHz I think rise and fall time would be long. I will look through the archives. Bob On Thursday, February 20, 2014 10:12 PM, Hal Murray wrote: jim...@earthlink.net said: I sample at 100 kHz with 16 bits on a teensy3.. Neat. Thanks. How many effective bits? (when the input signal is 60 KHz it that matters) Can somebody give me a lesson in the tradeoffs between number of bits and sampling rate? I know of one special case. If your ADC is only 1 bit, you don't have to worry about AGC. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New WWVB modulation format receivers (NOT)
NOTE: THE FIRST FIVE LINKS DID NOT SHOW AS COMPLETE ADDRESSES -- I AM NOT SURE WHY, SO YOU WILL HAVE TO COPY THE LINE AND INSERT INTO YOUR URL LINE. Hi Bob, Here are a couple of HP Appnotes, in PDF form, that will get you started in your quest. Some of the references to standard frequency transmissions may be somewhat outdated but the overall data is still valid. The first one is the original publication done in the early 1960's and the next two are a rewrite done in the 1970's. http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52_Frequency_and_Time_Standards_5989-6171EN.pdf http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-1_Frequency_and_Time_Standards_5989-6183EN.pdf http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-2_Frequency_and_Time_Standards_5989-6247EN.pdf http://www.ko4bb.com/Manuals/05)_GPS_Timing/The_Science_Of_Timekeeping.pdf And finally, here is an appnote about counters, generally, that is worth reading http://www.ko4bb.com/Manuals/HP_Agilent/HP_AN200_frequency_counters_1997.pdf There are plenty of other publications, but no need to overload you too early in the game. The stuff above will give you a basic understanding of the fundementals of which your questions to this list are centered omn. 73....BillWB6BNQ Bob Albert wrote: My TS-940S acts as though it receives okay at 60 kHz. Not great sensitivity but it does receive. Most HP GPS receivers are expensive ($400?). I was hoping to get some results with what I have, although I'm willing to cobble up some circuitry. I assume if I can receive the signal, I can figure out how to decode it and/or use it as is. How does one use a 1 pps signal to get precise frequency measurement? Maybe use it as a time base for a counter? My counter has 1 pps as well as 0.1 pps for 10-second count. I would assume signal fading would cause some timing uncertainty due to finite rise and fall time. And at 60 kHz I think rise and fall time would be long. I will look through the archives. Bob On Thursday, February 20, 2014 10:12 PM, Hal Murray wrote: jim...@earthlink.net said: I sample at 100 kHz with 16 bits on a teensy3.. Neat. Thanks. How many effective bits? (when the input signal is 60 KHz it that matters) Can somebody give me a lesson in the tradeoffs between number of bits and sampling rate? I know of one special case. If your ADC is only 1 bit, you don't have to worry about AGC. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New WWVB modulation format receivers (NOT)
Hi Zim, With but a very few exceptions most broadband Amateur radfio trancievers do not do well below 500 KHz even though many allow for tuning below 500 KHz. BillWB6BNQ Graeme Zimmer wrote: I have a Kenwood TS-940S transceiver that can receive 60 kHz but I have never heard anything Where are you? It must be deaf as a post. I can hear WWVB in Australia ! (or at least I could till JJY-60 started in 2001) ... Zim ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts < 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Is this measurement for real?
Hi Magnus, If the TAPR module you are referring to is the ICS-501 thing, that is really not suitable for this purpose. Equally, neither are the DDS chips. Besides never being right where you want them you have the spurii to deal with. Way too much filtering required. These two items aside from being surface mount have the added requirement of needing a damn cpu to tell the DDS what to do, not too mention the additional circuit board space. For a fixed frequency requirement it is much easier and cheaper to do it with a proper PLL and a good but inexpensive VCXO. Which, by the way, I found a small stash of the VCXO's on the right frequency for $25 each from a highly reputable US manufacturer (an over stocked run). And, TOO BOOT, I have the layout all done in through hole intended to fit in a $15 ABS EMI/RFI shielded box about 6.7 inches by 3.3 inches. But, thanks for the suggestions, BillWB6BNQ Magnus Danielson wrote: Bill, On 12/09/2013 02:30 AM, wb6bnq wrote: Hi Dave, My question was more centered on determining your expectations. I ran into an even worse condition with the cheap sound card, in my shop computer, I used for the Frequency Monitoring Tests (FMT) ran by Connie (K5CM). Being in a space with no temperature control at all, the sound card had a 7.0 Hertz variation over a few minutes. Clearly, it was a crystal going wild. As an experiment, I decided to rip out the crystal and replace it with the output of a HF synthesizer dialed to the proper frequency. My synthesizer, and other LAB equipment, is locked to my house standard which is monitored (not controlled by) with GPS. As expected, the results were spectacular ! I ended up with a measurement process that had a resolution of 120ns, and maybe somewhat less. At 1000 Hertz that is an uncertainty of +/- 1.2e-10. I did not try to account for ground loops or other anomalies; and the sound card was some cheap $18 item with no spectacular ratings in and of itself. I am now finishing up on a project to replace my expensive commercial synthesizer so it can return to test equipment duty. If you are interested in what I am doing in that regard, email me about it off list. As for the TS-2000 radio, I have not studied it, per se. But like a lot of these modern radios there are several possible error points within their design that could cause offsets and drift that may affect the outcome depending upon your application. However, if you are using a common analog detection type radio in the "AM" mode, then the radio does not matter to the outcome. The radio only serves as a mixer, albeit an expensive one. For example, when comparing an approximate 10 MHz unknown signal, the mixing action provides four (4) more decades of resolution if the output of the mix is 1000 Hertz. If using a modern DSP radio in the "AM" mode you may have to account for possible slight errors in the internal codecs (A>D/D>A). The only two error points that matter (using "AM" in the above example) is the local signal generator used to beat against the unknown incoming signal and the computer's sound card stability. If both are tied to your "House Standard," then it is totally up to the quality of your local standard's stability and accuracy. There are dirt cheap DDS-modules to buy from China, based on AD DDS-chip. If you need help with the reference frequency, you might want to use that TAPR module for clock-stepup. I don't think the TAPR module does the frequency you want straight away. Just to give you some ideas to follow up. It will be much cheaper and compact than your RF-generator today, and considering you already is listening to a stepped down signal, the purity is good enough for the purpose. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Is this measurement for real?
Hi Dave, My question was more centered on determining your expectations. I ran into an even worse condition with the cheap sound card, in my shop computer, I used for the Frequency Monitoring Tests (FMT) ran by Connie (K5CM). Being in a space with no temperature control at all, the sound card had a 7.0 Hertz variation over a few minutes. Clearly, it was a crystal going wild. As an experiment, I decided to rip out the crystal and replace it with the output of a HF synthesizer dialed to the proper frequency. My synthesizer, and other LAB equipment, is locked to my house standard which is monitored (not controlled by) with GPS. As expected, the results were spectacular ! I ended up with a measurement process that had a resolution of 120ns, and maybe somewhat less. At 1000 Hertz that is an uncertainty of +/- 1.2e-10. I did not try to account for ground loops or other anomalies; and the sound card was some cheap $18 item with no spectacular ratings in and of itself. I am now finishing up on a project to replace my expensive commercial synthesizer so it can return to test equipment duty. If you are interested in what I am doing in that regard, email me about it off list. As for the TS-2000 radio, I have not studied it, per se. But like a lot of these modern radios there are several possible error points within their design that could cause offsets and drift that may affect the outcome depending upon your application. However, if you are using a common analog detection type radio in the "AM" mode, then the radio does not matter to the outcome. The radio only serves as a mixer, albeit an expensive one. For example, when comparing an approximate 10 MHz unknown signal, the mixing action provides four (4) more decades of resolution if the output of the mix is 1000 Hertz. If using a modern DSP radio in the "AM" mode you may have to account for possible slight errors in the internal codecs (A>D/D>A). The only two error points that matter (using "AM" in the above example) is the local signal generator used to beat against the unknown incoming signal and the computer's sound card stability. If both are tied to your "House Standard," then it is totally up to the quality of your local standard's stability and accuracy. BillWB6BNQ quartz55 wrote: Well, Bill, I just don't know. I think that's why I asked. However, I did measure it again over 2.5 hrs and I got a roughly 500uHz drift pretty much all in one direction. I'm wondering if this is telling me I'm cabable of measuring 1mHz with some amount of success, I realize I will have to keep repeating this to see what happens in the long term. I've never tried to measure these small increments before and was wondering if others have had success doing this or am I chasing a rabbit down a hole? I did try using the WSPR software to measure freqs and that seemed to be all over the place, plus there's no way to record it over time except manually. I tried recording the WWV 500/600 Hz AM audio freqs with Speclab and it's so noisy it's hard to get a good plot, but from looking at the plots I did make it seems to be in the range of 20mHz variation, but pretty much centered on the freqs. I also measured some AM stations and I had drifts of 56 mHz for a 1030 KHz station, and I have measured the DSP drift as around 14 mHz. Do the AM stations really drift around that much? I thought they were pretty stable. When I measure the service monitor locked to the Rb, I get much less drifts than actual stations, like I said, around 15 mHz and that seems to relate to the fan in the TS2000 going on and off. Dave N3DT ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Is this measurement for real?
Hi Dave, Well, the question is do you think that is good or bad for the sound card ? BillWB6BNQ quartz55 wrote: I've been testing my soundcard measurement capability with Speclab, so I hooked my LPRO Rb to lock my Moto Service Monitor, fed the 1K audio out into the sound card and I measured the freq over about a half hour. I got a spread of about 107uHz. I've tried a few other things through my TS2000 using a 1500Hz tone from the USB and I can see when the fan goes on and off although I have the RX main osc locked to the GPSDO with the XRef from VK3HZ. I can only assume the drifting in the RX is due to the DSP processing crystal drifting with temp. I get about 13mh drift on that. Anyhow, here's a shot of the 1000Hz directly into the soundcard with Speclab. http://i251.photobucket.com/albums/gg287/DogTi/time/1k30m_zpsc4173981.jpg I almost don't believe it, does anyone else? Dave N3DT ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble 34310-T EFC Question
Bob, Most EFC circuits are relatively high impedance, i.e., around 50K. So, we are talking micro amps of current flow. If there is jitter it is most likely somewhere else in the circuitry OR you are seeing the "natural " noise in the GPS system. BillWB6BNQ Bob Stewart wrote: I think I may need to change the LPF feeding the EFC in my GPSDO to get rid of dithering jitter. Is there any point in adding a resistor and cap in the EFC line, or do I need to go back and change the values in the op-amp circuit feeding it? Currently an op-amp directly feeds the EFC pin. I guess this boils down to something like: is there any meaningful current flow in EFC circuit in this oscillator? Or should I add them but will I probably have to change the existing filter, as well? Bob - AE6RV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Self-correcting crystal
Hi Mike, Far more interesting, at least to the Time-nut community, is the article just above the one you reference. BillWB6BNQ Mike Naruta AA8K wrote: An interesting NIST brief: Perfect Faults: A Self-Correcting Crystal May Unleash the Next Generation of Advanced Communications < http://www.nist.gov/public_affairs/tech-beat/tb20131105.cfm#dielectric > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Need a schematic of Trimble 2003 era Thunderbolt RX
Hello Bob, First, there are no schematics available unless you want to, besides nondisclosure agreements, probably pay a HUGE amount of money to Trimble, if they would even entertain such an idea. Second, the 1pps output is a very fast rise narrow pulse that requires a very fast oscilloscope to even see. The easier way would be to use a pulse stretcher of some sort to make the pulse wider so that slower scopes could see it. As for the 10 MHz signal, how would a DC voltage have any relationship to the AC signal of the 10 MHz ? You would need to build an AC detector to monitor the signal output. BillWB6BNQ Bob Burchett wrote: Anyone have a link or PDF of the T-Bolt schematic? We are "never satisfied" with how things that seem to be working fine might fail one day in our critical environment SO: The object of the game is so if the T-Bolt fails to provide the 10 MHz signal that the loss of it will trigger a fail-over mechanism to a backup source so we built up a monitor-keys-a-controller circuit that watches the 10 MHz and while we DO have the Trimble PDF manual it doesn't have a schematic AND: Issue 1 is: We are monitoring the 10 MHz output of the T-Bolt and it appears to be AC coupled so this isn't as easily detected and we want to tap-in before the coupling capacitor to get a straight DC coupled signal for our special signal monitor circuit; that is one reason for schematic need PLUS: Issue 2 is: We see NO signal coming from the 1 PPS BNC jack and we hear that this is a port that can be enabled/ disabled and we are hoping one of you know how to enable it to output the 1 PPS which we might use to drive the monitor circuit OR: Optionally: how we might rewire it so we can get 10 MHz out of that "unused" jack to feed our monitor circuit. Thanks! Robert L. "Bob" Burchett WB6SLC Certified Communications Engineer Enterprise Electronics 22826 Mariposa Ave. Torrance CA 90502 Direct line: 310.534.4456 FAX: 310.534.1233 Website: www.EEonTheWeb.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP5061B Beam Tubes
Hi Bert, Any chance of some high resolution photos ? BillWB6BNQ ewkeh...@aol.com wrote: Twelve years ago I did disassemble a regular and a high performance tube, the only negative effect was I joined time nuts. The guts still decorate my window sill. The only parts inside that may be temperature sensitive are some copper wires with a clear coating. Every thing else is metal or ceramic. Bert Kehren In a message dated 9/23/2013 5:44:22 P.M. Eastern Daylight Time, j...@miles.io writes: I've always wanted to try baking the entire tube to vaporize any accumulations of Cs metal outside the internal oven. Is that what you did, Paul? If some of the free cesium metal near the detector can be recondensed at the oven end, or just redistributed uniformly throughout the tube, it might render a noisy tube usable again. The point at which cesium vaporizes is 250C / 482F, and that seems like it could be survivable unless there are thermoplastic structures or insulation sleeves inside the tube for some reason. The operation might be tricky, because while you wouldn't want to heat the tube sufficiently to vaporize all of the remaining cesium in the internal oven, you would also need to bake the tube for quite some time to heat its internal structures uniformly, since it's basically a vacuum bottle. Outgassing from various internal materials and structures would also be a concern. Something to try with a tube that is otherwise ready for the scrap heap... -- john, KE5FX Miles Design LLC -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts- boun...@febo.com] On Behalf Of paul swed Sent: Monday, September 23, 2013 12:52 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP5061B Beam Tubes Tom I added 10 degrees and used the built in temp sensor in the tube as a gauge. So its sort of accurate to say 10 degrees. I remember evaluating the temp several ways. I did not return it to original temp as I believed at the time I was baking out the last few Cs. What your saying in the threads very interesting. But don't have time to go back and adjust or reconnect the old oven controller. I would have to look at all of that again to see whats needed. I did this about 2 years ago its in the time nuts archive I suspect. Regards Paul. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] ThunderBolt Display - Update
Dear Mr. Adam Maurer (VK4GHZ), It really has nothing to do with your accolades, accomplishments or the number of posts made on a list, chat room, forum, or even Youtube videos. Your attitude is an entirely different issue, however. Mr. Robert Atkinson (G8PRI) treated you with respect and merely questioned why you posted if you do not bother participating (which you openly admitted) in the list. Hardly a rebuke of your persona, let alone any accolades or accomplishments. Yet you felt, in a most disrespectful way, compelled to drag him through the mud as though he was mere trailer trash without the slightest of merit. This is far more telling of your character then Roberts. I especially liked your "tall poppy syndrome." Referencing it shows you have serious narcissistic issues with your pedigree. The Time-nuts list has a stated purpose with the intent being a high SNR. That is, a high signal to low noise concept. Admittedly it has been getting out of hand more often than not lately. Using the "Email Reflector" as a communication medium for Time-nuts was chosen because it required the least amount of maintenance and served the purpose intended. It was not intended to be a chat room or forum. Just for the record this "list reflector" was established after the year 2000, even though you think it is so 1990's. Notably, your apparent supposition that someone's worth should be graded by the number, as apposed to the quality of the posts, is quite illuminating. Sharing, one of your claims of renown, is something we do on the Time-nuts list. Is it because they are looking for handouts ? Possibly some, but for most it is an educating effort or a peer review sort of thing. A kind of comradery, that is, openly sharing a common interest. As for "free enterprise," no, I have nothing against it. A number of list members produce items and have mentioned them on the list. The list was and is not intended for one's captive audience for marketing purposes. Your three messages and admitted non participation violate the previous sentence. Your petty, vindictive, verbally abusive and very nasty attack on Mr. Robert Atkinson shows a serious lack of maturity and was totally uncalled for. So, my NO vote still stands as you are not worthy of our company. BillWB6BNQ Robert Atkinson wrote: Hi Adam, I have copied this to our outmoded reflector. At least it's low noise and high quality. Sorry but dispite having been a licenced amateur for 35 years, I don't meet your 55+ demographic. I am aware that amateur radio has an aging demographic. That is why I have tutored for the UK licence for 30 years with student ages as low as 10. If you paid $3k for 50 double sided PTH PCBs you need to find a new supplier. I HAVE invested my own money in group projects (not time nuts), in one case an PIC driven LCD display add on for an instrument. I was able to sell these on ebay for $75 and to list/group members for $50. Circuit, source code and Hex file are published and freely available. I also supplied programmed PICs on request. So you are wrong in your statement "I seriously doubt somebody like you would" (invest in making up kits for a group. I do value my own time which is why I don't waste it on email forums full of people who have lots of opinion but no knowledge. You are correct, I don't contribute much to Time Nuts, I'm here to learn. I have contributed the odd manual PDF (originals purchased and scanned by myself) and some bits and pieces to members off-list. I also sell support software on PROM for other equipment, again at discount to relevant list members and with full details available. Many people do prefer to pay me to program devices, but at least I give them the option and assistance to do it themselves. Don't know what you typed into google, but when I put g8rpi in the third item was an open design for a low noise high voltage power supply of mine. You don't have to waffle on on youtube to contribute! You seem very fond of your voice and face. You imply your display is not a commercial product. I guess its not as it does not appear to comply with C-Tick, FCC or CE requirements :-) I'm aware of the time and effort required to make webpages, I've had formal training on the subject. I don't have a webpage, I contribute directly to specific groups. I don't need to boost my ego online. Your main website looks like a shop to me. Your other webpage http://www.qsl.net/vk4cp/ is "interesting" Your other "product" the Icom Multi-send looks a great design, or not. $79 for a PIC 3 Sil relay a few connectors and an undrilled case.  On your display, why no circuit? looking at the pictures it has TWO 28 pin Microchip devices. If these are both MCUs I don't think much of your coding skills My di
Re: [time-nuts] ThunderBolt Display - Update
Well Robert, In his Youtube video he says it is fully assembled, so no code, schematics or programmed cpu would be forthcoming is how I would interpret it. Up Shot is this is just shameless promotion. From my 99% complete "Timenuts list" database of saved messages going back to Jan 2006, his first appearance on the list was last year on Oct 3, 2012. This is his third message to the list with all three messages being a sales pitch for his product. It certainly seems to be a one-way gratuitous relationship to say the least. I don't mind people talking about, describing and offering their efforts to the list. But, I do mind when it seems that is the only purpose of their involvement. So, I would vote to have him removed from the list. BillWB6BNQ Robert Atkinson wrote: Hi Adam, If you "do not normally monitor this email reflector" or contribute to it, why are you using it it promote your commecial product? Are you going to make the circuit and code (or programmed MCUs) available to list members?  Robert G8RPI. From: Adam Maurer To: time-nuts@febo.com Sent: Thursday, 12 September 2013, 6:56 Subject: [time-nuts] ThunderBolt Display - Update Hello all An update: ThunderBolt Display started shipping over a week ago. 31 out the 50 have already been sold. I have made a video on the display, and you can see a working example here: http://www.youtube.com/watch?v=BSSZ6BcggBo Any new orders for the “jumbo� sized green and standard sized inverted blue variants will incur a 2 week wait, as these LCDs are only ordered in as-required. I do have a number of standard sized green units available for immediate shipping though on a first-in basis. I am away for 3 weeks in October, so if you want a display sooner than later, you should consider placing an order in the next few days, as it take 2 weeks for the LCDs to arrive. For more information of this device, please refer to: http://vk4ghz.com/thunderbolt-display/ You will find the latest revision of User Guide and Tech Supplement PDFs available as well. PayPal is welcome on the proviso I receive the full amount and you take care of any PayPal fees, if applicable. (This changes from one region to another) One way to avoid fees is to make sure your PayPal account has funds in it, and never draw upon other accounts (especially a credit card). Once these are gone, they are gone, and 130 units will be out there in 12 countries (so far). I do not normally monitor this email reflector, so please email me directly, if you want to obtain a ThunderBolt Display. Cheers, Adam, VK4GHZ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LPRO questions...
Hi Alan, That is a good question. Perhaps I was out of line using the word dimple. Some of the bulbs I have seen had what could be described as a small dimple or well. I guess the main point I was trying to make was having the bulb stationary during the cooling process so the material would gather together as one glob. Perhaps, those who have rejuvenated these bulbs could provide a keener sense on this point. BillWB6BNQ Alan Kamrowski II wrote: Hi Bill, Where is the dimple? The bulb end looked circular and smooth? Do you mean the other end (back end which is visible even when the bulb is installed)? The bulb end points towards the entire assembly... Thanks, Alan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LPRO questions...
Alan, It won't be splattering, but more of a shadowing or dull glazing, kind of like gray colored sun glasses. The heating is to cause the sun glass effect coating the glass bulb to go back into a gas and, when cooled down it will solidify, pooling into the DIMPLE that should be oriented in the down position to collect said pooling. It is a very small amount of Rubidium material grayish silver in color. The only purple is when heated to the gaseous state it is excited as a plasma by an external RF signal around 100 MHz. So, the two big questions are was it heated long enough to cause all the material to go back in to a gas form and then while cooling it was held fixed so the DIMPLE was pointed down long enough ? Hopefully you got it right, otherwise try again is all you can do. Personally, I don't think 60 to 90 seconds would be long enough, but I don't actually know that, just a feeling. If you got it right, perhaps there are other issues like part values that have drifted. BillWB6BNQ Alan Kamrowski II wrote: Hi, Well, I had it apart so I went ahead and tried the heating process on the lamp. I don't see any splattering on the lamp at all of purple material, but I added some masking tape to the threads and put it in a drill to rotate it. I hit it with a hot air station at 350 deg C and rotated it for 60-90 seconds or so. The end result is a lamp that went from 3.5V to 3.7V. Did I do it long enough or hot enough? The repair guide I saw said something about a hot air gun and those can be 300-600 deg C... Thanks, Alan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Rb video - UPDATE video for you critics
To the Group, Here is a link of Gerry's update video addressing some of the concerns expressed here and other places. http://gerrysweeney.com/10mhz-rubidium-frequency-standard-and-signal-distribution-amp-follow-up/ BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advantages of differential oscillator structures?
Hi Attila, I gather you did not fully read the paper ? In normal CMOS circuits, the higher the oscillator frequency the higher the amount of current drawn to reach that higher frequency. So, the two oscillator system was used to keep time and "wake" up the higher frequency oscillator (for example the 12.8 MHz) when the radio was in operation. When not in operation just the lower frequency oscillator (32 KHz) was used to keep time and provide a "wake" of the microprocessor and the higher frequency oscillator needed for the radio operation. This paper presents a circuit topography that allows the low current operation at a high frequency (12.8 MHz) thus reducing complexity. This in turn allows the design and manufacture of a radio system using one crystal oscillator at a frequency of 12.8 MHz (example in the paper) with the low power advantage that previously required two oscillators. BillWB6BNQ Attila Kinali wrote: Hi, While reading up on oscillator circuits i stumbled over differential oscillator structures (see [1] for example). But sofar i have been unable to figure out what the exact advantages of a differential oscillator strucutre in general are. Would someone here be so kind and give me some hints where to look? Thanks in advance Attila Kinali [1] "A High-Stability, Ultra-Low-Power Differential Oscillator Circuit for Demanding Radio Applications", by David Ruffieux, 2002 http://www.imec.be/esscirc/ESSCIRC2002/PDFs/C02.01.pdf http://www.imec.be/esscirc/ESSCIRC2002/presentations/Slides/C02.01.pdf ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] SDR Radio Opinion- Next Question
Hi John, I don't think you quite got it yet. All of those types of "Dongles" have no frontend filtering and no gain control (AGC). Basically it is a "diode" (so to speak) looking at the spectrum from DC to Daylight, even though they have a limited range. So, yes, there will be birdies and aliasing issues. There is no software from a unit's manufacturer for the "All Frequency" observation mode that Amateur radio and other hobbyists are using it for. Aside from all that , they do come in a plastic case and there is some excelent control software, notably Simon Browns HDSDR, that can control a number of these types of umits. As for spectrum software, the best one is Spectrum Labs which can take I/Q input. See the respective web sites for more information. Both of these packages are FREE. http://www.hdsdr.de/hardware.html The SDR software hardware page http://www.qsl.net/dl4yhf/spectra1.htmlThe Spectrum Lab software. BillWB6BNQ J. Forster wrote: OK. Thanks everybody. Can you please reccomend a make/model? I'd like something like: <75 to >1300 MHz USB Ability to function as a crude SA. Not crawling w/ birdies or aliasing issues. Will run on Win XP. Demod selecttable for all modes at all frequencies. In a package, rather than a loose PCB. <$150 Prefer: SMA rather than RCA or F Receiver and SW from same vendor. Suggestions, please. Thanks, -John === ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How quartz crystals are (were) fabricated
Hi Brooke, The can style should be marked on it. The designation "CR41 or 2" is hanging around the back of my mind. I would have to drag up the few I have around here somewhere and look at them again. 73....BillWB6BNQ Brooke Clarke wrote: Hi: Speaking of old crystals, I found the crystal in the URC-4 survival radio is packaged in an axial lead machined metal can. See Fig. 9 at: http://www.prc68.com/I/URC4.html or go straight to the photo at: http://www.prc68.com/I/Images/URC410b.jpg Does anyone know the package designation and if any other crystals are available in that package? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RS 232
Hi Bert, My attitude is if you are going to provide an RS-232 port then do it properly (min of +/- 3 volts & max of +/- 25 volts). RS-232 is still a popular item in the hobby controller world, although USB is gaining ground. In so far as stability goes, RS-232 is much cleaner and easier to handle in the micro coding compared to USB. With that said, there is nothing wrong with providing both, it just makes the coding a bit harder. If you need long lines and want common mode suppression then utilize RS-485, a derivative of RS-232. You could also use TOSLINK, the fiber optic lines used in the audio field. The components are fairly cheap compared to other forms of plastic or glass (more expensive) fiber products. Most products will handle up to 5 MHz at reasonable distances. If you are careful in selecting the TX and RX port parts it can go up to 15 MHz at the top end, especially at short distances. Irrespective of all that, the power source has no relationship to the RS-232 or USB for that matter. 73BillWB6BNQ ewkeh...@aol.com wrote: I do not understand your question, I am referring to low noise applications like counters for dual mixers or other AV measurements, but also Shera and even Tbolt where external noise should be kept to a minimum. When you chase 1 E-14, isolation is key and I always like to err on the cautious side and as I stated we use blue tooth or USB but in the case of USB there are always H11 in the circuit. Some still like to use RS 232 and the subject came up and I have on my boards H11's like on the counter Corby uses but he ended up using an external power source and I like to eliminate that requirement. David had the right answer using the power that the RS 232 mouse uses out of a DB 9, started looking but I do not have one any more and I can not find any data. Bert In a message dated 7/25/2013 2:48:43 P.M. Eastern Daylight Time, ma...@non-stop.com.au writes: Hi Bert, I am sure your circuit is clear in your head, but would you mind attaching detail? You have perked my interest with the "low-noise" keyword ;) -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Thursday, 25 July 2013 11:39 PM To: time-nuts@febo.com Subject: [time-nuts] RS 232 Since joining time nuts over four years ago I have not used a single MAX 232 chip. Two reasons MAX do not give me isolation and do generate noise in critical applications. I prefer the use of two H11 opto couplers which work perfect. On the receiving end the diode along with a current limiter and blocking diode for the negative level works perfect. On the output side a power source is needed. If one uses an USB adapter it does have the + 5 volt which again works perfect. How ever many prefer to use RS 232 direct and that is why I hope to get some comments and suggestions from the list. Corby used on our counter circuit that he described a separate power source. Present MAX circuits use a + 1.4 volt threshold but considering legacy the question is what should the voltage swing be to make it compatible for most PC's and what options exist to get the necessary voltage. In the past other pins on the RS 232 port where an ideal power source. Still an option? Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Spectrum Analyzer Suggestions
Perry, I did not pay attention to bottom frequency of the hp SpecAn in my last post. Do you actually do something below 100KHz ? BillWB6BNQ Perry Sandeen wrote: List,  I just purchased a HP 3585 spec analyzer on E bay for a reasonable price. I wanted this instead of the 181 series as the range was more to what I’d be using and it was of a newer vintage. The 3585a goes from 10 Hz to 40 MHz which is a most useful range for my purposes. so far, so good.  The problem is I didn’t know the beast weighed a svelte 88 pounds! Double Hernia time!  What I’d appreciate advice for a used spec analyzer in the $1,000 range that is at least much lighter. A smaller size would also be a benefit.  I probably would never use it above 100 MHz. A slightly smaller screen would be OK.  Suggestions appreciated.  Regards,  Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Spectrum Analyzer Suggestions
Well Perry, You could consider an IFR A-7550 SpecAn. They are not HP but still a decent little SpecAn that is just a bit bigger then a TEK-453 scope. It covers from 100KHz to 1GHz. Shop carefully to make sure you get one with atleast the internal tracking generator option. DO NOT rely on pictures because the tracking generator connector is there even if no option. There is also an internal receiver option, but that only works when you are at zero span and truthfully, not all that useful, but nice to have. It also has an internal battery option, however, the battery pack is quite expensive and unless you actually need it, it is a complete waste of money. If it comes with a battery, expect it to not be in very good shape. The battery pack is made up of large round 2 volt lead acid cells and when left discharged will leak acid. BillWB6BNQ Perry Sandeen wrote: List,  I just purchased a HP 3585 spec analyzer on E bay for a reasonable price. I wanted this instead of the 181 series as the range was more to what I’d be using and it was of a newer vintage. The 3585a goes from 10 Hz to 40 MHz which is a most useful range for my purposes. so far, so good.  The problem is I didn’t know the beast weighed a svelte 88 pounds! Double Hernia time!  What I’d appreciate advice for a used spec analyzer in the $1,000 range that is at least much lighter. A smaller size would also be a benefit.  I probably would never use it above 100 MHz. A slightly smaller screen would be OK.  Suggestions appreciated.  Regards,  Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
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Re: [time-nuts] Carrier meter
AH-HA, thank you Bob. Now it makes some sense ! BillWB6BNQ Bob Camp wrote: > HI > > He's answering a question from about a day ago on the R-390 list. > > Bob > > On Jun 13, 2013, at 7:59 PM, WB6BNQ wrote: > > > Perry, > > > > Just out of curiosity, who the hell are you talking to and more importantly > > what > > are you talking about ? ? ? ? > > > > BillWB6BNQ > > > > > > Perry Sandeen wrote: > > > >> List, > >> > >> Wrote: I > >> have noticed that my Carrier meter doesn't consistently go to Zero. The > >> Meter > >> itself seems fine. > >> > >> Your questions are answered in the Y2KR3 > >> manual. See Chapter 11. > >> > >> While all on the list are willing to help, much > >> angst and lost time can be avoided by perusing chapters 9 and onward. > >> > >> Regards, > >> > >> Perrier > >> > >> > >> > >> ___ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Carrier meter
Perry, Just out of curiosity, who the hell are you talking to and more importantly what are you talking about ? ? ? ? BillWB6BNQ Perry Sandeen wrote: > List, > > Wrote: I > have noticed that my Carrier meter doesn't consistently go to Zero. The Meter > itself seems fine. > > Your questions are answered in the Y2KR3 > manual. See Chapter 11. > > While all on the list are willing to help, much > angst and lost time can be avoided by perusing chapters 9 and onward. > > Regards, > > Perrier > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap 9.8Mhz Sa.22c's
Hello Mark and crowd, I own one of these and I can guarantee that it CANNOT be moved without changing the crystal, tweaking a micro-minature coil value, and changing the firmware. And NO !, the company would NOT send out the firmware needed. However, if you wanted to spend between $500 and $1000 they would fix it for you. While there is a DDS inside, it and the crystal are part of Rubidium frequency locking loop. The actual output frequency is generated by dividers in a big ASIC/FPGA/whatever device. YES, that output frequency is derived from the crystal frequency. They start by choosing a output frequency which selects the crystal frequency. The crystal is multiplied up to some frequency and mixed with the output of a DDS (also driven by the crystal) to produce the final frequency multiplied further to get to the Rubidium resonance. So, without a change in the firmware, there is no way to tweak the unit more than a very small amount. BUT all is not lost. The 9.8304 MHz frequency is related to the common RS-232 modem frequencies. It is also related to the common sound card frequency of 24.576 MHz. There it is possible to phase lock it to 10 MHz. BillWB6BNQ "Mark C. Stephens" wrote: > These are 9.8304Mhz, is possible to move them to 10Mhz? > > http://www.ebay.com/itm/Symmetricom-SA-22c-9-8304MHz-Precision-Rubidium-Oscillator-5V-and-15V-NICE-/261223397404 > > -marki > > Kind Regards, > Mark Stephens > > Mark Clemens Stephens | Customer service engineer | Non-Stop Computer Ltd > * +61 2 9011 8186 | ( +61 428 256 334 | * > ma...@non-stop.com.au<mailto:ma...@non-stop.com.au> > > Non-Stop Computer PTY LTD > 79 Devon St > North Epping > NSW 2121 > Australia > Timezone: AEST (UTC +10) > > Email: serv...@non-stop.com.au<mailto:serv...@non-stop.com.au> > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 9390 GPS RX
Hi Mark, First order of business is to NEVER turn adjustments if there is an indication that a fault exist. So, you need to determine if the heater coil is open, or the voltage to the coil is proper, or the thermistor sensor is bad, and etc., etc., etc., Be very careful around the thermistor as they easily break and the leads are most certainly brittle after all these years. Sounds like you need to verify all the power supply voltage levels are correct before anything else. Most importantly, do not jump to conclusions to quickly. BillWB6BNQ "Mark C. Stephens" wrote: > Okay, I pulled the black box cover off and was greeted by a picture of how > things should be made. > After some considerable time staring at the veritable work of art, I thought > I saw the crystal hiding behind the foam. > So I gently removed the foam and marked on the xtal is 79 degrees C. > Cool, Well actually that's hot! > So I have powered it up for 30 minutes and measured the temperature with a > very accurate temperature gun I use for measuring preheating on rework jobs. > Huh, its sitting dead on 60 degree's. > I think therein, lies our problem, the crystal never reaches turning point. > According to the fine manual, Increasing R8 lowers the temperature. > Therefore, If I decrease R8 It should theoretically, increase the temperature? > The conundrum is, Shall I just change R8 value or perhaps there is something > else wrong. > What do you think Guys, R8 or something else? > I am not going further without some of the abundant collective wisdom and > experience contained in the time-nuts members! > > -marki > > -Original Message- > From: Mark C. Stephens > Sent: Friday, 24 May 2013 2:01 AM > To: Discussion of precise time and frequency measurement > Subject: RE: [time-nuts] 9390 GPS RX > > Ed, > > Okay, Lying there I couldn't stop thinking about its lone Ball. > > So I setup the jig, Powered it up and yep, after half an hour the frequency > is doing the up/down swing thing. > Interesting, I just happened to come across that page that reckons you can > rejuvenate a lamp with a heat gun. > So I thought, hmm that's easy, let's try that, so I did, and the frequency is > not swinging so quickly now. > Could be an symptom, but I think coincidence. > Anyway, next I connected a DVM to the xtal volts output monitor pin as per > the manual. > Uhuh, its swinging in tandem with the frequency swing of the 10 Mhz output > swing. > Gets to 2V and then swings down to -2V > Nowhere near the 8V defined in the manual. > So I tried adjusting the trimmer as per the manual. > Nope won't go above 2V at the fully clockwise limit of the trimmer. > > So that is where I am at. Looks like I will have to pull it apart and fix it > then. > Does it sound/look like the crystal has gone out of adjustable range? > > -marki > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Mark C. Stephens > Sent: Friday, 24 May 2013 12:22 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] 9390 GPS RX > > Hey Ed, Well I have its Ball (just one? ;) Efratom out on the bench. > > Seems they built this stuff to service, huh? Nice. > > I managed to make a mating connector out of 2.54mm pitch header strip as per > your suggestion. > Whew, that was my biggest concern! > > Anyway, its after midnight and I have a full day ahead, Looking forward to > getting this old gal working again. > I can't help giving the 9390 a reassuring pat every time I walk past it ;) > its sitting there merrily running off the house standard although PDOP hasn't > gone below 4 which has me a tad worried. > It seems, I have become quite attached to this 9390 :p > > -marki > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Ed Palmer > Sent: Thursday, 23 May 2013 1:16 AM > To: time-nuts@febo.com > Subject: Re: [time-nuts] 9390 GPS RX > > On 5/22/2013 4:58 AM, Mark C. Stephens wrote: > > It's a 9390-55024 > > > > I have plugged my counter into the Efratom rubidium oscillator thing and > > disconnected the EFC. > > > > It is actually wobbling ~ +/-650Hz, peaking as much as +/- 1KHz. > > So, hazarding a guess, something is very wrong inside the black box thing. > > Is it really wobbling around randomly, or is it sweeping up and down. > Your counter could be fooling you by taking 'snapshots' at intervals > dependent on the gate time setting. If the frequency is wobbling randomly > that would likely mean an actual fault in the FRK rath
Re: [time-nuts] 10Mhz Sine from Square Wave Synthesizer
Hi Andy, If it is at 9.8304 MHz, don't even consider trying to fool with anything inside. While it does have a DDS inside, it is of the newer design where the DDS is inside the loop that determines frequency for locking the Rubidium. It requires a crystal, coil and firmware change to move it to 10 MHz. Unless you want to spend some big money, Symmetricom will not help you at all. How do I know ? Well, I have one and tried ! Even got the proper crystal sent to me, but did not get any firmware. Also there may be a super small surface mount coil that needs to be changed to make the replacement crystal oscillate. The 9.8304 MHz is related to various baud rates and also some clocking frequencies for sound cards. So, don't throw it away as it is still useful. If nothing else you could phase lock a 10 MHz oscillator to it as there is a connecting ratio. BillWB6BNQ Andy Bardagjy wrote: > Alright, so it seems that it's possible the Symmetricom SA.22c that I've > got might be set to 9.8304MHz. That may be programmable to 10MHz, but it > might require a DDS otherwise. > > Nevertheless, if the oscillator is set to 10MHz it seems the consensus is > to construct a LPF. > > Luciano, thank you for sharing your design, did you wind your own > inductors? Odd values.. Typically when designing filters I start by fixing > the inductor values and work backwards... > > John, thanks for your input, you reminded me that LFP performance often > depends on source impedance. To the MMIC amplifier, you'd be amazed what > you can do with an opamp these days. I was amazed reading the datasheet for > the LTC6409 a 10GHz GBW, 1.1nV/sqrt(hz) fully differential opamp. With a > gain of one, the frequency response is totally flat out to 1GHz. > > http://cds.linear.com/docs/en/datasheet/6409fa.pdf > > Perhaps something like a LT6600-15 might be a complete solution for me - > it's a fully differential amplifier with a 15Mhz 4 pole LPF. > > http://www.linear.com/product/LT6600-15 > > Thanks for your input, I'll be sure to keep everyone posted on my project's > progress. > > Andy Bardagjy > bardagjy.com > > On Mon, May 20, 2013 at 12:03 PM, Luciano Paramithiotti > wrote: > > > Hi Andy, > > > > The simplest way is to use a low pass filter with a notch capability for > > the second and third harmonics. > > You can find the schematic and response for 5 and 10 MHz here: > > > > http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf > > > > ciao, > > > > Luciano > > timeok > > > > see: www.timeok.it > > > > On Mon, May 20, 2013 at 1:30 AM, Andy Bardagjy wrote: > > > > > Hi folks, I recently picked up a Symmetricom SA.22c rubidium oscillator. > > > According to the datasheet, it outputs a square wave with programmable > > > frequency (well you can pick among some set of frequencies). > > > > > > I'd like to build up a small circuit locked to the square wave output > > which > > > outputs a 10MHz sine wave for use as my "house clock" for my various > > > instruments (spec an, counter etc). I of course could distribute the > > square > > > wave, but am concerned about harmonics, among other things. > > > > > > The FE-5680A uses a AD9830A DDS to synthesize its output. Is a DDS the > > > right way to go - in terms of performance, phase noise and so on? > > > > > > I suppose I could do this with a tank or some other analog circuit, but.. > > > > > > Andy Bardagjy > > > bardagjy.com > > > ___ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > > > > > > > -- > > Luciano > > Timeok > > visit : www.timeok.it > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] AD9830 DDS question
Hi Corby, I just went there and tried it. It seemed to work correctly. I am using OPERA and an older version at that. I also tried it in Explorer 8 and it worked. Not sure what to tell you. By the way I am still running Win XP. BillWB6BNQ cdel...@juno.com wrote: > Hi, > > I'm trying to program an AD9830 DDS chip removed from an FE rubidium > unit. > > I have done it in the past with no problem. > > However now when I go the AD website and try to use the device > configuration assistant it faults out saying internet explorer has a > problem with the page and it closes. > > If I use Firefox the page comes up and I can enter frequencies but the > code words section stays empty! > > Any ideas? > > Is there a version of this program I can download and run locally? > > Thanks, > > Corby > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OCXO Adjustment Question
Hi Fred, It sounds like you are turning it too far and too fast and expecting too much from it. In old items, like what you have, those adjustments are fairly coarse and required a very slight touch, then a wait and see, then another very slight touch, etc.,. It sounds like you are turning a physical capacitor. If it is the kind that has two little ceramic discs and a small screw type head for adjustment, often the variable ceramic disc part would become lose where the screw head would not really be fully attached to the disc causing backlash. Oscillators that only have a single adjustment like that are not at the high quality end of things. When you make a mechanical adjustment there will need to be some time for the mechanically induced stresses, along with some electrically induced stresses upon the quartz blank to dissipate before the final results of the adjustment will be realized. All of the above is assuming no temperature change. The time frame of the Cushman 5110 was back when very high quality oscillators were very expensive and for the intended purpose were not really necessary. The Cushman only needed a given amount of accuracy to meet the requirements over a certain time frame to qualify for adjusting commercial radios to FCC specifications. With that said, to improve the time base of the Cushman, you should consider replacing the internal reference oscillator with one of the modern oven controlled 14 or 8 pin IC size oscillator packages. They are way above what is in the Cushman, of very small size and can be adjusted via a resistive ten turn potentiometer to a much higher degree and will hold its frequency to a much closer degree. You do need to be careful which one you select as most of the small IC size oscillators do not have a voltage tuned connection. On eBay, you can find ads for a Marion 89A which is the kind you would want for such a project, that is assuming the base reference of the Cushman is 10 MHz. If it is lower there a ways to use the Marion and achieve the needed frequency without a lot of space consumed. Of course you could disassemble the Cushman oscillator and replace the variable capacitor. That would improve things a little but no where near what can be done with the Marion 89A. Hope this is helpful, BillWB6BNQ Frederick Bray wrote: > This might be slightly off-topic, but probably there is a time-nut who > knows the answer. > > I am trying to adjust the 10 MHz OCXO in a Cushman 5110 service > monitor. I am using a frequency counter driven by a GPSDO. Perhaps > someone can educate me about a couple problems I am encountering. > > I tried making small incremental adjustments but after I am done, the > frequency drifts several Hz and then re-stabilizes at a new value. When > I make further adjustments, I notice strange behavior. For example, if I > initially turned the adjustment clockwise to increase the frequency, it > will now decrease if I turn it clockwise and increase if I turn it > counter-clockwise. On the next adjustment, it will reverse again. > > Is there some correct procedure to adjust an OCXO? > > Many thanks for any suggestions. > > Fred Bray > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: eBay Contact Congress
Hi John, I also got one of these emails. It appears to be genuine, especially as two different sources directed to by Drudgereport, are talking about a rush to pass Internet tax regulation during this week without time for people to review the proposal and the White House pushing the same point. No matter your view point about eBay, their concern is real and should be of concern by everyone else. Particularly, as it is being handled to push it through so fast without the proper vetting. BillWB6BNQ "J. Forster" wrote: > Hi, > > I recieved a very odd communication, apparently from eBay, this morning. > It is a request to contact Congress about sales taxes on internet sales. > > It APPEARS to be genuine, but I'm unconvinced. > > Has anybody else received this email, and is it for real? > > Puzzled, > > -John > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] ngTADD-1
Hi Kevin, You could try TOSLINK fiber cable. Yes, it is not the best as far as fiber cable goes, but it seems to be a viable method. I got the idea from a Ham in, I believe, Colorado who was using it to isolate his 10 MHz for a project. If you are interested in viewing what the other guy did, I will search for his web site. I haven't constructed the project yet, but do have a 75 foot run of the TOSLINK cable and a TX & RX TOSLINK ends. I had to buy the three components at three different places. The TOSLINK receiver came from Mouse (p/n 757-TORX177F,T) and cost $1.31. The TOSLINK transmitter came from DIGIKEY (p/n 1080-1428-ND) and cost $0.866. At the time, for whatever reason each supplier had the one end but not the other. The cable came from a company called Monoprice who had the lowest price of $23.28 for the 75 feet and $1.58 for a 1.5 foot piece. I bought one of each of the two cables and 10 each of end pieces to experiment with. You would need to use an inverter at the least to square the single for transmitting and another at the receive end to buffer the receiver. You also may need to use a PLL, like a 74HC4046A or better yet a NXP 74HCt9046A, to clean up a long run, however, that is just speculation on my part. The guy in Colorado was using a short 1 foot link. As for the distribution amp, it has been about two years, or a little more, since the TADD-1 supply has run out. The MAX amp used in the TADD-1 is no longer available but Analog Devices has an exact replacement. For my use, I have been working on a layout that would duplicate it but also add the TOSLINK feature so I can get the house standard over to the radio room from my (so-called) Lab. JUst food for thought, Bill....WB6BNQ Kevin Rosenberg wrote: > On Apr 22, 2013, at 7:13 PM, Bob Camp wrote: > > U, e. Even with all the mods, a 4501 is a fairly low resolution > > device. It's an amazing little box and I have several of them. Some (but > > not all) with the mods actually done correctly. > > Ummm, apologies for the errant posting that should have been a private > message to N8UR. > The 4501 was directed about a previous post to John. > > The question for John about his new distribution amplifier was so that I > could place my > RF and thermally-shielded 10811-60109 in the corner of my concrete basement. > Then, > run 100 ft of galvanically-isolated coax to my lab. > > Now that's its public, do you have suggestions for the coax? I was thinking > about LMR-240 > for its double-shielding and low tempco at 10 MHz. > > Thanks, > > Kevin > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Changing FE-5650A frequency?
Alexander Wright wrote: > On 07/04/13 21:55, WB6BNQ wrote: > > Hi Alec, > > > > I am going to agree with Robert (G8RPI) on his assessment, particularly as > > the dip switches are clearly visible in one of the pictures. Although I > > wonder why Robert feels unfortunate about the [ two chip DDS arrangement ] ? > > > > It matters not the number of chips that make up the DDS. Why ? Because > > the actual physics package and its electronics has nothing to do with the > > DDS in the older designs. That is, the signal output of the physics > > package is a fixed frequency (around 50.255 MHz) that you could capture > > and feed to a more modern DDS if necessary as replacement of the old one is > > probably not going to happen. However, if it is working then once you get > > to a frequency you need you probably not touch it again. So no loss there. > > > > As for calibration, there is a hole on one side of the can that has a > > multi-turn pot that adjusts the "C-field" current. The C-field is a very > > fine frequency adjustment. You first adjust the C-field pot to its lowest > > setting (as in frequency), then set the DDS to the closest frequency on > > downside of where you want to go and then adjust the C-field pot to come up > > on to the frequency. The C-field pot is a really fine adjustment, so we > > are talking very small movement that will require patience, a better > > reference and at least a > > oscilloscope to watch the drift rate over a very long time. A truly time > > consuming experience. > > However, if you leave that C-field pot alone, you will most probably be > > inside 1 part in 10 to the minus 9th. > > > > The most recent designs have the DDS in the control loop for the physics > > package. In the new internal design in order to change frequencies you > > need to actually change the BASE crystal frequency, the DDS and the > > firmware to get a new output frequency. So basically a real pain in the > > ass. > > > > As for the foam that is sandwiched in between the boards, I agree with > > Robert that it is for temperature stability in varying environments. If > > the unit is kept in a normal room all the time then the foam is not a > > concern and could be carefully cleaned off. There is some other components > > that have white stuff that looks more like an RTV type substance used to > > hold down a component like what is seen in photograph > > IMG_20130407_102937.jpg at the two toroids, That I would leave alone. > > > > Your finding the 12+ MHz just confirms that the design is very similar to > > that described in the FTP file I provided. Make sure you record the switch > > settings before you change them so you can return to a reference point. > > > > Although you did not indicate, I assume you downloaded the FTP file ? > > Please let me know so i can reduce the storage level as it is not my site > > although I have use of it on a short term basis. > > > > Thank you, > > > > BillWB6BNQ > > > Bill, > > Thanks for your input and sorry for the slow reply! > > So, I've had a look at the datasheet and it looks like the output > frequency should be Fin*(tuning word)/2^32... I thought I'd check if > this matches up. > > The tuning word was set to x4134111F (towards the inside of the board > seems to represent 1 and towards the outside, zero. > > Assuming 50.255MHz going in that gives 12.799985 MHz output! > Perfect. Pretty much exactly what I'd measured. Alternatively I could > assume that the output is 12.8MHz exactly which sets the input frequency > to 50.2550586MHz - i wonder which assumption I should use when changing > the frequency? I'd like to adjust it to put 10MHz out, skip the 4000 > series logic divider and remove/change the output filter. > > Regards, > Alec Hi Alex, Your alternate assumption is the correct one. Working the formula backwards with the assumptions that the 800 KHz is spot on would then dictate that the DDS out is exactly 12.8 MHz with the final value of the physics package being 50,255,058.6495 based upon my HP-35s calculator. Many construction and environmental factors affect the actual final frequency of the physics package. Plus there is some small variance about the center frequency with which signal levels are still strong enough to allow functionality. The C-field adjustment allow for tweaking within that small variance. Fortunately, this ability allows for putting the Rb right on the assumed true frequency. Provided you have a higher reference source (i.e., Cesium or a well tamed GPS
Re: [time-nuts] Changing FE-5650A frequency?
Hi Alec, I am going to agree with Robert (G8RPI) on his assessment, particularly as the dip switches are clearly visible in one of the pictures. Although I wonder why Robert feels unfortunate about the [ two chip DDS arrangement ] ? It matters not the number of chips that make up the DDS. Why ? Because the actual physics package and its electronics has nothing to do with the DDS in the older designs. That is, the signal output of the physics package is a fixed frequency (around 50.255 MHz) that you could capture and feed to a more modern DDS if necessary as replacement of the old one is probably not going to happen. However, if it is working then once you get to a frequency you need you probably not touch it again. So no loss there. As for calibration, there is a hole on one side of the can that has a multi-turn pot that adjusts the "C-field" current. The C-field is a very fine frequency adjustment. You first adjust the C-field pot to its lowest setting (as in frequency), then set the DDS to the closest frequency on downside of where you want to go and then adjust the C-field pot to come up on to the frequency. The C-field pot is a really fine adjustment, so we are talking very small movement that will require patience, a better reference and at least a oscilloscope to watch the drift rate over a very long time. A truly time consuming experience. However, if you leave that C-field pot alone, you will most probably be inside 1 part in 10 to the minus 9th. The most recent designs have the DDS in the control loop for the physics package. In the new internal design in order to change frequencies you need to actually change the BASE crystal frequency, the DDS and the firmware to get a new output frequency. So basically a real pain in the ass. As for the foam that is sandwiched in between the boards, I agree with Robert that it is for temperature stability in varying environments. If the unit is kept in a normal room all the time then the foam is not a concern and could be carefully cleaned off. There is some other components that have white stuff that looks more like an RTV type substance used to hold down a component like what is seen in photograph IMG_20130407_102937.jpg at the two toroids, That I would leave alone. Your finding the 12+ MHz just confirms that the design is very similar to that described in the FTP file I provided. Make sure you record the switch settings before you change them so you can return to a reference point. Although you did not indicate, I assume you downloaded the FTP file ? Please let me know so i can reduce the storage level as it is not my site although I have use of it on a short term basis. Thank you, BillWB6BNQ Alexander Wright wrote: > On 07/04/13 17:56, Robert Atkinson wrote: > > Hi Alex, > > These units were used as timing references for secure communication systems > > (Havequick). see ebay item 130832014630. Unfortunatly they are an older > > design with a two chip DDS. The other problem is that the "M" designation > > is for military and means they have been partially encapsulated with > > polyurethene foam. You can cut it away but it is very easy to damage the > > PCB. Frequency setting is by DIP switches (under the foam) allowing full > > range of frequency selection. However the output filter is narrow so you > > can't go far from 800kHz. > > Did you buy all seven? > > > > Robert G8RPI. > > > > > Robert, > Thanks for the info! I bought one of these wondering what they were, > took it apart and found the rubidium clock and figured it must be worth > something (more than the 15 quid he was asking) so I bought the remaining 6! > > I've taken the foam off the top PCB and i've found that there's a > 12.8MHz signal being produced which is then being divided down with an > 800kHz logic chip. I should imagine the filter must be on the circuit > board below? I might try changing the frequency > of the DDS chip, removing the frequency divider and tinkering with the > output filter. Do you have any info on what sort of filter I should > expect to find? > > Thanks, > Alec M0TEI > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Changing FE-5650A frequency?
Hi Alec, You may be in luck. However, I would need some additional pictures, particularly of the connector on the bottom, also some of the inside. The primary physics package is a stand alone analog Rubidium frequency standard that outputs 50.255* MHz frequency. That signal is used to drive various output board configurations, included inside the unit, to provide a customer required output frequency. The more recent revised units (they look the same) use a new digital scheme that is much more of a hassle. The one that I and a number of people are familiar with is the 5650-option-58 model whose output was a 1pps. To get the 1pps the 50.255+ MHz signal was used to drive a Direct Digital Synthesizer (DDS) that produced 8.3+ MHz signal that was then divided down via normal TTL dividers to produce the 1pps. The DDS is capable of being changed to other frequencies up to about 20 MHz, however, the filter following the DDS needs to be changed or bypassed to properly filter the new frequency. Bypassing is the easiest method but would require using an external filter to get rid of aliasing and spurs. I put together a zip file of various information on FEI-5650-option 58 that will help you get familiar with the family line. If you have problems with the link let me know. Also, after you get a successful download let me know so I can reduce the FTP storage level, thank you. http://pages.suddenlink.net/stevewingate/cryptic1/for alec on 5650-option-58.zip BillWB6BNQ Alexander Wright wrote: > Hi all, > I've recently ripped some FE-5650A's out of some old equipment, but they > seem to be a custom build, here you can see they have the option just > listed as "-": > http://cambridge.m0tei.co.uk/files/IMG_20130330_232647.jpg > > They seem to be single rail (15v) supply with an 800kHz output. I > wonder, does anyone know if it's possible to change its frequency? As > far as i'm aware this model doesn't have serial control. > > Thanks, > Alec M0TEI > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Time shown as two horizontal bars
Hi Bill, Interesting idea. One of the problems you are going to have with normal available displays is being able to distinguishing the individual "elements" as you get further away from the clock. So it sounds like you may have to construct your own display area so that the "elements" are further apart. Doing so would allow for some embellishments, such as using a different colors for the 10 and 30 minute LEDs. Equally so, you could use 24 LEDs for hour marks using two different colors for day and night. Likewise, you could reduce the number of LEDs by using 9 for the minutes in one row. A second row would have 5 for the 10 minute marks. The third row would be the hours with just the 12 LEDs but by using dual color LEDs you could cover day and night. Just thought I would complicate your project BillWB6BNQ Bill Hawkins wrote: > Looking for a long, thin horizontal clock display for use above or below > a flat screen TV. > > Tried searching for "bar clock" and got a lot of useless hits. > > What I'd like is a display that is about half an inch (12 mm) high by > 12-18 inches long (30-50 cm) that is just two rows of 60 or 120 leds. > One row is labeled 0 to 59 (or 60) and the other is labeled 0 to 12. The > display does not stay at 12 or 60 but jumps back to zero. Power line > frequency is an adequate reference, as long as it always has the same > 86,400 seconds per day, except for added leap seconds. There should not > be a clock frequency adjustment. > > 60 seconds worth of line cycles bumps the minute bar (30 if it has 120 > leds), and 5 minutes bumps the hour bar (150 seconds for 120 leds). > > The clock is set (after startup and power outages) by four buttons on > the back - minutes, increment, decrement, hours. > > Have any of you connoisseurs of time seen such a clock? How about a bar > of leds that could be used to make a clock? > > Bill Hawkins > > P.S. Currently re-reading Terry Pratchett's "Thief of Time" - a whole > new way to look at time in a funny and perceptive story. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Chris, Can you point me to the web site where the TI Launch Pad is sold for $5 including shipping ? Thank you, BillWB6BNQ Chris Albertson wrote: > snip > > I plan to use a $5 TI Launch Pad. But > basically the same over all ideas he used. At $5 each with shipping > included TI is losing money. The device is self programming via a > USB connection. > > snip > > -- > > Chris Albertson > Redondo Beach, California > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
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Re: [time-nuts] Brooks Shera
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Re: [time-nuts] FE-5680A DDS Board/PIC Code
Hi Herbert, Nice work ! A few comments that may help you in your quest. There are two primary methodologies used in the FEI-5680A Rubidium. It appears, from your picture, what you have is the older style that is analog for control of the Rubidium frequency control loop. A VERY GOOD THING ! Why, because the analog "C" field pot is active in such a unit, permitting adjustment allowing you to put it right on the mark. This easily allows you to extend, externally, the "C" field control and be able to put it in an external loop with a GPS without much trouble. In the first methodology, the original designed was, totally, an analog control. The micro controller is used to talk to only the DDS which is outside of the Rubidium control loop. The Rubidium control loop starts with a 50.+ MHz oscillator frequency multiplied up to the Rubidium and the feedback from the photo multiplier is fed back to control the 50.+ MHz oscillator. This 50.+ MHz is the reference frequency for the DDS on the board in your picture. The second methodology is a bit more complicated because FEI switched to digital control of the Rubidium frequency loop. Here, an internal 60. MHz oscillator is used as a base signal. A DDS, whose reference is from the same 60 MHz oscillator generates the required offset and mixed with the 60 MHz to produced the final multiplied signal to the Rubidium filter. The photo multiplier is sensed and eventually runs a DAC to control the 60 MHz oscillator. The problem with this approach, due to the computerization and digital stepping, is you can get close but not necessarily right spot on for frequency. Depending upon your "house" standards, that may or may not be an issue. To put it in perspective, I think the adjustment process in the newer methodology is either parts in the 10E-12 or -13. The output frequencies that the customer sees are derived via circuitry outside the loop like the old method except they have switched to using either an ASIC or FPGA of some sort making it quite difficult to determine what is going on. Equally so is the fact that the ASIC/FPGA's are controlled by software. Of course, FEI is not going to be forthcoming on the internals, nor do they want to tell how to use their computer link to control the Rubidium unless you are a customer. As a hobbyist, you are left with a much harder unit to integrate into external control mechanisms. Even though the "C" field pot is still there it is not active in the unit. Someone or more have been investigating methods to find a proper point with which to inject an outside DC signal to attempt a "C" field like control. I do not know what their success has been. FEI's part number system is really two different processes. The FEI-5680A number is the generic case and layout style, etc. and another "order" number is attached that tells what is actually arranged inside. So, the upshot is the older arrangement is easier to play with. Hope this has been helpful, BillWB6BNQ Herbert Poetzl wrote: > I'm new to the time-nuts community, so I simply start > with a short info on how I got into this situation :) > (skip forward to if not interested) > > Not long ago, I decided to build a reasonably good > frequency counter for my personal use and maybe if > the result is simple and elegant, I'll publish the > details so that everybody can build one ... > > It was clear to me, that it had to be able to count > up to at least 1GHz and thus show at least nine, > better ten significant digits, so a precise time base > is required. > > After some online searches and investigations, my > best options seemed to get a very stable oscillator > and a high quality time reference to sync with, which > in turn brought me to the idea to use a cheap rubidium > normal and somehow tune/measure/sync it via GPS or > DCF-77/MSF-60. > > Reading a lot of documentation and blogs from all over > the world (sometimes in translation :) shed some light > on the rubidium normal requirements, which I defined as: > > - has to have a 10MHz output not just the 1PPS > - has to be programmable (i.e. can be tuned) > - must be cheap > > I quickly found two different RB standard models, > readily available on ebay for a reasonable price, > namely the Efratom FRS-C and the FEI FE-5680A. > I finally decided to go with the FE-5680A, mainly > because I liked the package. A seller was quickly > found offering something titled: > > 'FE-5680A Rubidium Atomic Frequency Standard > Oscillator Transceivers 10Mhz Out' > 'Programmable from 1Hz to 20MHz' > > Little did I know what that actually meant ... > > When the units (I ordered two of them) arrived, I > couldn't wait to test if they actually work and get > a lock, so I quickly
Re: [time-nuts] VCXO in a watch timing machine
Hi John, OK ! It is good that the other resistors were there. It is also good that a lower EFC voltage lowers the frequency. I am not sure what standard values are available to you in the UK. I picked a standard value in the US that would roughly center the pot's range equally around 2.1 volts. So, I would suggest paralleling a 5.1K 1% metal film resistor across the lower 3K resistor. Attaching from the bottom of the pot to that resistor string's ground point would probably be easier then trying to attach directly across the SMT 3K resistor. The 5.1K added resistor puts the bottom resistance value at 1888.9 Ohms. The whole string would nominally be 5888.89 Ohms and ups the current in the string from 0.743 ma to 0.883 ma. A small change and should not be a problem as to power dissipation in the upper 3K. The voltage at the bottom of the pot should be near 1.67 volts and the top of the pot should be near 2.55 volts. That should place the range so that the VCXo goes below 18 MHz. If not then select the next lower standard value. Try to obtain 1% metal film at 1/8 watt or second best carbon film at the same ratings. Do not use the OLD carbon composition type resistors. As Bob points out and I also agree, if your unit looks like the type I saw on the web site, then the 18 MHz oscillator most likely runs the computer system. That does not necessarily mean it is also the clock that is clocking the A/D that is digitizing the sound. So, varying the 18 MHz may not change your results. The important clock, for accuracy, is the one that clocks the A/D inside your unit. Time will tell. After you add that resistor and then readjust the 18 MHz based upon your counter, you will know if the watch is on time the next day. If not then it will require further study of the circuitry. Good luck, BillWB6BNQ john wrote: > Hi > > Some very good questions - thanks for the responses. No schematic (or > documentation of any description - Ebay purchase), but I've done some > dismantling and had a poke around with a multimeter. This is what I > find: > > The power supply provides +5.2V and +/-6V. Strangely, the silkscreen on > the board power connector says +5V, +8V, -8V and -24V. The power supply > has no components or wires for this latter voltage, so that's a bit of a > mystery. The -24V rail disappears off into some components, so maybe > it's an 'option' on another model? Anyway, let's not get sidetracked. > > The 1k pot is sandwiched between two 3k resistors (surface mounted on > the back, so not immediately obvious). I get 0V - 2.2V - 3V - 5.2V, so > only 0.8V adjustment range. The lower the voltage, the lower the > frequency, and vice versa, so I could just short the resistor that's > connected between ground and the pot? > > Modern mechanical watches are relatively impervious to changes in > temperature - balance springs and balances are made from materials which > are much better in that regard than their carbon steel forbears, which > required split bi-metallic balances to compensate. > > I agree that 18MHz does seem an odd number. The counter can work with > watches that beat at 5, 5.5, 6, 7, 8 and 10Hz so you'd think it would > relate to those in some integer way. > > Regards > John > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] VCXO in a watch timing machine
Ed,
Interesting point, I hadn't considered that the frequency should be off !
{32768
x 550 = 18,022,400.000} So, maybe it has drifted the other way ?
However, looking at the Witschi web site suggest that their instruments sense by
picking up audio or vibration via some kind of sensor as they talk about
checking
motors and buzzer noise from the watch. That being the case it is more likely
the 18 MHz should be right on frequency.
Well, unless we hear back from the guy and he answers questions put to him, we
really won't know whats up.
BillWB6BNQ
Ed Breya wrote:
> How do you know that the frequency range is incorrect for the function?
> Assuming this is for calibration of wristwatches, maybe the idea is to
> set them to some nominal value at room temperature, then expect them to
> drift to the "right" frequency at skin temperature or so. There would
> have to then be some relationship between the approximately 18 MHz and
> the ideal 32,768 Hz watch crystal frequency.
>
> If the idea is to divide the 18 MHz down to an accurate version of 50/60
> Hz or 1 Hz, then yes, it looks like something's wrong. But, does it need
> to be a VCXO, or just settable to the right frequency? I believe that
> 18.00 MHz is a standard frequency for VCXOs and TCXOs, so readily
> available from typical vendors, or you could build an oscillator as good
> as needed. The package dimensions seem like a standard 14 pin (only 4
> are used) DIP style - very common.
>
> I think most of those modules use a limited tuning voltage range like
> 0-5 V if the supply is +5 V. If you haven't already, check to be sure
> the full tuning voltage range is covered at the module. You can usually
> get a little higher frequency by exceeding the tuning voltage -
> especially if there's nothing to lose anyway if it's damaged - but
> unfortunately it's hard to get lower frequency since the varicap diode
> will reach zero or forward bias if you go very far the other way.
>
> Also, if the supply voltage is off, it could have drastic effects on
> operation. Changing the supply voltage a little can affect the frequency
> and tuning range, so this is another option for slight adjustment - but
> may give unpredictable results.
>
> Ed
> ___
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Re: [time-nuts] VCXO in a watch timing machine
Hi John, First question is do you have a schematic ? Second question: Is the 1K pot directly across the VCC to ground ? Or is it in the middle of a resistor string ? Normally, the EFC pin has a nominal center point that is around 1/2 of the VCC going to the VCXO module. Also, the EFC pin's input resistance is fairly high, in the order of around 50K. So it would seem unlikely that the 1K pot is all there is between VCC and ground. That would imply 5 ma of current flowing through the 1K pot, which seems a little high for the needed function. A typical current level would be more like 1 ma. So, before you go crazy changing out the VCXO check to see if the 1K pot is in a resistive string. If that is the case, then you could adjust one of the fixed resistors to put the pot range so that it covers above and below the 18 MHz mark. As previously mentioned, it would pay to measure some of the circuit parameters to make sure things seem proper. BillWB6BNQ john wrote: > Hi > > I'm hoping to get some information on the VCXO that sits in my watch > timing machine. The timer is a Chinese clone of a Witschi timer - the > heart of the thing is an 18MHz VCXO marked 'SCTF 03'. There's a BNC > socket that outputs the crystal frequency and a 1k pot to adjust the > frequency. > > The snag is that I can only adjust the frequency between 18,002,359Hz > and 18.000,958Hz. I have a Hewlett Packard and a Thurlby Thandar > frequency counter which give me readings that broadly agree - I'm > quoting the HP because I trust it more! The hardware frequency in my > scope doesn't have the resolution at 18MHz, but agrees that it's > fast.These figures translate to a maximum of 11.32s/day fast and a > minimum of 4.63s/day fast. This is borne out in practice by the > behaviour of watches - if I adjust them to 0s/day, then they are fast, > but if I aim for -5s/day then they are about dot-on. > > So if my workings-out are correct, I can 'pull' the VCXO by 78ppm, > which seems reasonable, but offset away from the nominal 18MHz. Is this > a common failure of VCXOx? Can anything be done about it? The device is > about 18.35mm long by 10.8mm wide (and 7.7mm high) - is this a standard > size, and if so who would sell an 18MHz VCXO (UK)? > > Any advice gratefully received. > > Regards > John > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] question for expert time guys
Hi Rick, You would do better putting a small GPS receiver in the mobile and transmit with a 2.4 GHz Blue tooth transmitter. The GPS devices can be gotten very small (your thumb would just about cover it up). They are also very light and draw very little power. That would save you two transmitting and receiving stations. Clearly the software would be infinitely easier as you would not need to deal with all the timing issues. GPS would provide the position information and its time count for each report, if that mattered. Some representative GPS receivers can be research at the following location: https://www.sparkfun.com/categories/4 They also have various transmitter devices for blue tooth, WIFI and Zigbee. You can view these under the following category: https://www.sparkfun.com/categories/16 This is only one place that provides such things for hobbyist. There are others, as well as, going direct to the manufacturers for such OEM products. I do not know if you are aware of it, but and finale product that transmits over the air may need FCC certification. Other sections might apply in certain circumstances. BillWB6BNQ Rick Harold wrote: > To time experts/EE's. > > I would like to triangulate a position of a device which moves using 3 > fixed positions devices of known location. > The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or > appropriate frequency. > These two type of devices (fixed and mobile) are all under my control and > thus customized as needed. > > The mobile device (not a phone, custom device) would be the least expensive > item. I'd like a range of 150 feet or better and accuracy of 3 feet or > better. > When manufactured these items they can be calibrated in order to adjust for > any variation in IC's, discrete components etc... > We can assume for now the temperature is constant 70 degree temperature. > Cost is the key design factor. > > The general flow is: > >1. base station 1 indicates we are determining position of device A. >2. Each base station 1, 2, 3 take turns pinging the device to determine > distance. >3. A ping consists of (something like, e.g. frequencies as examples) > -send 915mhz signal from base station to device > -device response ASAP on different frequency > -station waits and counts 'time' for return > -this is repeated N? times to get best avg/accuracy. > -The mobile device does not move very fast >4. Since delays of the process on each unit is calibrated the device and > base station would subtrack that time out from the results. >5. obviously with 3 distances we can determine the 2D position of the > mobile device > > I know the time accuracy is the key to count time = feet, 1ns. This > overall project is not new concept. How to make it "inexpensive" is key. > how inexpensive, very ;-) no OCXO or expensive components like that. > > That's my goal, and I'm looking for help on the design/thought process of > getting there. > I am open to a consulting arrangement for a fee, please email if you like. > I've worked with 'regular' EE's (I'm a software guy) but this time > accuracy is too much for them. > Esp. finding a way to do it inexpensively. > > Thanks for any thoughts. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] question for expert time guys
Hi Rick, You would do better putting a small GPS receiver in the mobile and transmit with a 2.4 GHz Blue tooth transmitter. The GPS devices can be gotten very small (your thumb would just about cover it up). They are also very light and draw very little power. That would save you two transmitting and receiving stations. Clearly the software would be infinitely easier as you would not need to deal with all the timing issues. GPS would provide the position information and its time count for each report, if that mattered. Some representative GPS receivers can be research at the following location: https://www.sparkfun.com/categories/4 They also have various transmitter devices for blue tooth, WIFI and Zigbee. You can view these under the following category: https://www.sparkfun.com/categories/16 This is only one place that provides such things for hobbyist. There are others, as well as, going direct to the manufacturers for such OEM products. I do not know if you are aware of it, but and finale product that transmits over the air may need FCC certification. Other sections might apply in certain circumstances. BillWB6BNQ Rick Harold wrote: > To time experts/EE's. > > I would like to triangulate a position of a device which moves using 3 > fixed positions devices of known location. > The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or > appropriate frequency. > These two type of devices (fixed and mobile) are all under my control and > thus customized as needed. > > The mobile device (not a phone, custom device) would be the least expensive > item. I'd like a range of 150 feet or better and accuracy of 3 feet or > better. > When manufactured these items they can be calibrated in order to adjust for > any variation in IC's, discrete components etc... > We can assume for now the temperature is constant 70 degree temperature. > Cost is the key design factor. > > The general flow is: > >1. base station 1 indicates we are determining position of device A. >2. Each base station 1, 2, 3 take turns pinging the device to determine > distance. >3. A ping consists of (something like, e.g. frequencies as examples) > -send 915mhz signal from base station to device > -device response ASAP on different frequency > -station waits and counts 'time' for return > -this is repeated N? times to get best avg/accuracy. > -The mobile device does not move very fast >4. Since delays of the process on each unit is calibrated the device and > base station would subtrack that time out from the results. >5. obviously with 3 distances we can determine the 2D position of the > mobile device > > I know the time accuracy is the key to count time = feet, 1ns. This > overall project is not new concept. How to make it "inexpensive" is key. > how inexpensive, very ;-) no OCXO or expensive components like that. > > That's my goal, and I'm looking for help on the design/thought process of > getting there. > I am open to a consulting arrangement for a fee, please email if you like. > I've worked with 'regular' EE's (I'm a software guy) but this time > accuracy is too much for them. > Esp. finding a way to do it inexpensively. > > Thanks for any thoughts. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Low noise power supplies?
YUP, The C-130 aircraft uses larger than car battery size wet NiCd to fire up the Genset that is used to start the Tubo-prop jet engines. Definitely has lower resistance then the Lead-Acid wet cell. BillWB6BNQ Arthur Dent wrote: > >But the only NiCd I know about are the AA sized ones. > > I have some of the wet NiCd batteries that are capable of > putting out 200A continuously. I'm assuming the internal > resistance is pretty low. ;-) > > Arthur > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Hi Ed, I seriously doubt you will be able to pull the 10 MHz crystal tht far off. International Crystal Manufacturering (ICM) http://www.icmfg.com/ still makes crystals for a reasonable amount (about $25) cut to order. That may be far easier than all the time you would spend bending and pushing things around trying stretch components. BillWB6BNQ Ed Breya wrote: > I've got to make a very clean 10.0594... MHz VCXO for a redo of one > of my old circuits. I previously used a 10 MHz ceramic resonator, which > was easy enough to push around in frequency. Of course, I have a couple > dozen of those somewhere, but can't find them now that I need them > again. I figured I'd just pull the ones out of the old circuit, but > since I did find a whole bunch of 10 MHz quartz crystals, I'd like to > revisit whether I can push one of those that far with decent results. As > I recall, the results of my previous experiments in doing this were less > than satisfactory, which is why I went with the ceramics. > > This would be a change of 60 kHz out of 10 MHz, or 0.6 percent - a > helluva lot for a crystal. The frequency will be exactly phase locked to > a reference. It doesn't need to have extremely high in-circuit Q or > long-term stability - just tunable to that magic number - the PLL will > do the rest. A conventional varicap circuit will provide the VCO-ness, > while the tuning range just needs to be enough to accommodate drift and > the initial setting. The power gain element will be a 74HC04 or 74HC86 > section. The PLL reference will be 59.4... kHz - way above the > necessary loop BW. > > Has anyone successfully pushed a quartz crystal that far off, with > reliable (still sort of a sharp resonance) operation and no spurious > modes? Any ideas? If this isn't practical, I'll just go back to the > ceramic resonator (which worked just fine), but I'd like to settle it > once and for all. > > Ed > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] hammond 77589
Hi Jean-louis, It looks very much like the main crystal in a Symmetricom Rubidium unit that I tried changing a crystal in. In my case the crystal was made by Bliley. It is about the same size as the standard 8 lead TO-5 integrated ciruit case except that it had just three leads on the bottom just like your unit. Is your roughly the same size ? Do you know or have a picture of what it came out of ? BillWB6BNQ Jean-Louis Noel wrote: > Hi all, > > Will someone know what it could be? > http://www.stben.net/DSC_0338.JPG > http://www.stben.net/DSC_0339.JPG > > Thanks for your help. > > Bye, > Jean-Louis > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Questions about TAC frontend, and some measurements
Hi Fabio, I am not crazy about your 10 MHz input circuit. You might want to consider investigating John Miles input arrangement at the following web site: http://www.ke5fx.com/ac.htm I used it to drive an input to a divider chip without the output resistor or capacitor. BillWB6BNQ fabi...@quipo.it wrote: > Hello, while waiting fot the final doom, or a new > job (tough times here) here is another update of > the work I'm doing, sorry for the looong mail, > hope I'm not boring the readers. > > I have a question about a some measurements I > made, and I'd like an opinion about a frontend > schematic I designed. > > First the question about the problem: > in this graph (bottom right) there is the time > interval between the PPS from the PA6H GPS > module and the 10MHz form the FE5680A, > uncrambled and corrected for linear drift. > The graph periodically makes big steps, and > this happens in the morning hours, in the > few captures I made so far the fact happens > around 6am-8am in the morning: > http://www.flickr.com/photos/14336723@N08/8294131424/ > another previous capture with span enough to > include 2 mornings: > http://www.flickr.com/photos/14336723@N08/8294131660/ > > I will make more tests to check if the problem is in > the gps receiver or in the FE5680 or in the way I'm taking > measurements. This will take a while. > Maybe there is a simple explanation that I cannot see > since I'm a total newbie i this field. > Where should I search first for the problem? > > How I'm taking the measurements: > the measurements are taken with the racal 1992 > connected to the point OutD in the centre of the > frontend I'm building: > http://www.flickr.com/photos/14336723@N08/8293076065/ > The OutD will spit out a short negative pulse, > the width of this pulse is the same (or very near) > than the phase time interval between the rising > edges of the pps and the 10MHz. > The counter logs the pulse width using a 100MHz > scope probe set to 10x, DC coupled. > > The plots are made using this script I wrote for the task : > http://pastebin.com/XmKQp9gR > The (rude) script tries to unscramble the data, remove > outliers and correct for linear drift. > If it's useful I will upload the raw log data. > > The frontend circuit: > As I wrote before I'm trying to feed a microcontroller > with 10MHz from a Rb oscillator and a PPS pulse from > a GPS module and see if I can obtain a good starting > point for building my own GPSDO. > Now I'm testing a front end that will present to the > micro both the PPS and 10MHz nicely squared, and > an analogue representation of the time interval between > the rising pulses of the sources. > > What do you think of the circuit I designed? > (thanks to many resources coming from > this list, I passed much time on ko4bb site > and many others I dont even remember, thank you > all!) here the asc file for LTSpice: > http://pastebin.com/94H78jxs > I'm using components I had around or scavenged > in scrap electronics I had. > The TAC seem to work, but now I need a better > opamp (the LM358 has too much current > flowing in-out of the inputs), here a pair > of captures taken directly from C1 capacitor, 90nS pulse: > http://www.flickr.com/photos/14336723@N08/8293075961/ > and a 50nS one: > http://www.flickr.com/photos/14336723@N08/8294131200/ > The red trace is the input GPS PPS. > > Fabio Eboli. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt oven / non-stable operating temperature
Hi Charles,
Well, perhaps you are not looking close enough. That is you need to be
observing
at a finer level of comparison. The changes, observed here and at another
location, are in parts in 10-10 to 10-11 range, sometimes larger. At one of the
locations there was a direct correlation to the air conditioning cycle.
BillWB6BNQ
"Charles P. Steinmetz" wrote:
> >That temperature sensor does have an effect on the final outcome as
> >it is part of
> >the internal equation. So buffering the ambient temperature is important.
>
> I've heard this before, but the evidence I have seen does not seem to
> support the proposition.
>
> While switching the Dallas chip in one, I used the opportunity to
> bring the chip temporarily outside of the Tbolt housing on a cable to
> investigate whether the Tbolt makes any internal use of the
> temperature data. Neither freeze spray nor bringing a soldering iron
> near the chip, when it was outside of the Tbolt housing and the Tbolt
> housing was well insulated from the changes in chip temperature,
> seemed to have any effect on the operation of the Tbolt, either
> normal or in holdover.
>
> I have also run Tbolts with the newer ("wrong") temperature chips for
> long periods, and have not observed any systematic differences in
> performance between them and units with the older chips, either in
> normal operation or in holdover. In Tbolts with the newer chips, the
> reported temperature often has little connection with the actual
> temperature and, at times, jumps abruptly, yet the Thunderbolts
> operate normally with no corresponding jumps in operating parameters.
>
> My supposition/conclusion is that the temperature sensor was provided
> so telcom operators could get a rough idea of the temperature in
> remote cell-site transmitter shacks, not for internal use by the Tbolt.
>
> As long as the Tbolt is housed so that its reported temperature does
> not change too rapidly, the oven control loop will keep the crystal
> very close to its set temperature over a wide range of ambient
> temperatures. I have used this approach and have also actively
> controlled the housing temperature, and have not observed any
> material difference in frequency or timing stability between the two
> approaches.
>
> Best regards,
>
> Charles
>
> ___
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Re: [time-nuts] Thunderbolt oven / non-stable operating temperature
Sarah, That temperature sensor does have an effect on the final outcome as it is part of the internal equation. So buffering the ambient temperature is important. You do not need to go crazy, but having it contained in a box with some small amount of heat applied and maintained by some controlling mechanism would be a good way to go. The amount of heat depends upon what extremes your location experiences over the day/week/year and the effective insulation of the container. Ideally you would want no temperature change, but, obviously, that is not practical, so a one degree variance would be a reasonable goal. BillWB6BNQ Sarah White wrote: > On 12/10/2012 6:10 PM, Arthur Dent wrote: > > I believe that the high temperature alarm you see is triggered at 50 degrees > > C. If that is what you're seeing without artificially raising the > > temperature > > of the Thunderbolt by insulating it so it can't radiate the heat, what I > > said > > about replacing the chip is correct but if it is staying within a few > > degrees > > over the course of the day and is in the 40 degree C range without being > > insulated, the DS1620 thermometer chip is o.k.. > > My particular thunderbolt seems to be from 2004, so I guess that manual > is at or around checked: > > ThunderBolt[tm] GPS Disciplined Clock User Guide Version 5.0 > > 5.0 is a version of the manual published in 2003 > > Table C.2.2 Environmental Specifications: > > Operating Temp: -0°C to +60°C > Storage Temp: -40°C to +85°C > > ... so I guess I shouldn't worry about a few degrees of difference in > the reported temp, especially considering that the sensor in question > isn't on the OCXO itself. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Switching oscillators
Bob, I don't know where you got your multiple versions. RETRACE deals with the object in a fully realized steady state operating condition, then removal of power for a period of time (usually stated in real specs as 24 hours) and then re application of power with a stated result. Really quite simple in concept. Its cousin, WARMUP, would describe a similar process assuming both are at a non operating nominal environment ambient temperature. Usually a RETRACE spec will state some amount of off period, like 24 hours. Unless we are talking super hot molten metal or a nuclear reaction, usually most things get to nominal room temperature inside of 24 hours. So, in that case RETRACE and WARMUP would mean virtually the same thing. BillWB6BNQ Bob Camp wrote: > Hi > > That's one interpretation and one method of measurement. The other method is > to measure frequency shift from say one hour after power on to 24 hours after > power on. A lot depends on the requirements of the system the OCXO was > intended to be used in. > > If you use the measure / power off / warmup / measure approach, you need to: > > 1) Define the time on before the first measure > 2) Define the power off time > 3) Define the warmup time > > Change any of those numbers and the retrace number will be different. > Generally the temperature(s) involved are also defined. The most common case > is that all of this is done at 20 or 25C. > > Bob > > On Dec 9, 2012, at 8:47 PM, "Tom Miller" wrote: > > > So if I understand it, you allow the OCXO several days of warm-up to set > > the frequency. Then when turned off for a while, then restarted. After some > > warm-up period, the retrace spec would give an indication of how close the > > frequency will be? > > > > Thanks, > > Tom > > > > - Original Message - From: "Bob Camp" > > To: "Discussion of precise time and frequency measurement" > > > > Sent: Sunday, December 09, 2012 7:58 PM > > Subject: Re: [time-nuts] Switching oscillators > > > > > > Hi > > > > Retrace assumes that the oscillator has some "normal" frequency that only > > moves according to the aging rate. Retrace occurs after the oscillator has > > been off power for some period. The rate of change is greater than the > > aging rate. Warmup and retrace are obviously inter-related. Warmup is > > generally described as a short term (sub 1 hour) process. Retrace is often > > looked at as a day to multiple day sort of thing. > > > > Since none of this is tightly defined, you will see various specs looking > > at the same issues a bit differently. Often those differences roll up to > > some sort of system requirement. > > > > Bob > > > > > > On Dec 9, 2012, at 7:45 PM, "Tom Miller" wrote: > > > >> Hi Bob, > >> > >> Can you give a good definition of retrace as it applies here? > >> > >> Thanks, > >> Tom > >> > >> > >> - Original Message - From: "Bob Camp" > >> To: "Discussion of precise time and frequency measurement" > >> > >> Sent: Sunday, December 09, 2012 7:24 PM > >> Subject: Re: [time-nuts] Switching oscillators > >> > >> > >> Hi > >> > >> Your TCXO will have the same sort of retrace issues as your OCXO. Past > >> some number of minutes (5,10,15 ) you will always be better with a modern > >> OCXO than with a TCXO. > >> > >> Bob > >> > >> On Dec 9, 2012, at 7:05 PM, WB6BNQ wrote: > >> > >>> Hi Joe, > >>> > >>> I think you all are not looking at this correctly. > >>> > >>> 1.First, as has been pointed out, a TCXO will vary around till the > >>> environment it is in has returned to its nominal operating temperature. > >>> > >>> 2.A typical TCXO is nominally spec'ed around +/- 0.5 x 10-7 > >>> neighborhood. Not a stellar number. > >>> > >>> 3.The real spec to look at is the "RETRACE" factor of a good OCXO. > >>> > >>> Many of the modern PCB CAN manufactures do not or are quite hazy on > >>> this point. Vectron, for example, on their double oven high > >>> performance WIDGET (model DX-170) claims a warmup time of 5 minutes > >>> to +-10ppb of final frequency, however, they also include this > >>> cryptic statement "(1 hour reading) @ +25DEGC" on the same spec. I > >>>
Re: [time-nuts] Switching oscillators
Hi Joe, I think you all are not looking at this correctly. 1.First, as has been pointed out, a TCXO will vary around till the environment it is in has returned to its nominal operating temperature. 2.A typical TCXO is nominally spec'ed around +/- 0.5 x 10-7 neighborhood. Not a stellar number. 3.The real spec to look at is the "RETRACE" factor of a good OCXO. Many of the modern PCB CAN manufactures do not or are quite hazy on this point. Vectron, for example, on their double oven high performance WIDGET (model DX-170) claims a warmup time of 5 minutes to +-10ppb of final frequency, however, they also include this cryptic statement "(1 hour reading) @ +25DEGC" on the same spec. I am not sure, but it suggests that they are reading the final frequency at the one hour point after turn-on. Taking it at face value, it suggest that the oscillator is within +/- 1 x 10-8 at 5 minutes. That is a whole decade better than the TCXO under any condition. Looking at something real like the HP 10811A/B Quartz Crystal Oscillator, you will see they spec the retrace as "Warmup 10 min. after turn-on within 5 X 10-9 of final value, at 25DEGC and 20 Vdc. See Notes 1 & 2. Notes: 1. For oscillator off-time less than 24 hours. 2. Final value is defined as frequency 24 hours after turn-on." Here, we are talking about two whole decades better than the TCXO ever could be. 4.So the real question is just what the hell are you doing at 10 minutes or less that would require all this worry ? ? 5.The real answer to your dilemma is to have some serious battery backup and if it is truly to be considered a critical necessity, then maybe you need a power generator that is automatic when the shore power drops. My two cents, BillWB6BNQ Joseph Gray wrote: For my use, I don't think the switching glitch will be a concern. Most of the time, the equipment will be in a standby mode. There is a high probability that the OCXO will be in use most of the time. I guess my original idea of simply waiting a sufficient time for the OXCO to warm up and then switching is probably the thing to do. Joe On Sun, Dec 9, 2012 at 3:16 PM, Bob Camp wrote: > Both would need some sort of timer to drive them. Both would disrupt the instrument when the switch took place. I know of no "cheap / easy" ways to take care of the switching glitch. There are fancy / expensive ways. > > Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to [1]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. References 1. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPSDO Alternatives - Bert's boards
Hello Bert, The boards look nice but tell me nothing of the circuitry. How about sending the schematics ?? That way I can appreciate what it is that you have. BillWB6BNQ p.s. By the way, what ever happen with that DMTD you were going to produce about three years ago ? ewkeh...@aol.com wrote: > Attached is my latest ExpresPCB layout of a GPSDO. A clear understanding > of the GPS limitations, a goal as to what I want to control ,focus on > attainability, reproducibility KISS, cost and tests of partials on > development > boards and what you see if you download the ExpessPCB software is on the > right the saw tooth correction, in the middle the analog board with opto > isolation to prevent ground loop and on the right the actual GPSDO. This > particular unit also allows you to link a 20 Hz offset FRS-C (part of my dual > mixer) to my house reference. Total material cost depending how many boards > one > buys is below $ 40. I will include this particular board along with other > designs on my next order and subsequently cut with a sheer. > The board on the right could be used by itself with minor modifications to > directly drive a FE 5680 if some one would step up to the task. Total cost > below $ 15. I use the analog board, which by the way is the most expensive > since it has a LTC 1655 and REF 02. > No dither 16 bits, dither 18 bits and depending on loop time, clock > frequency range starting at 3 E-9 and resolution up to 6 E-16. > Again I am only interested in to controlling a Rb which gives me way more > flexibility, the Rb's are either modified with a 10811 or in one case with > the M1000 and in the case of the FE 5680 a MV89 with a separate analog loop. > And in all cases the RB is temperature controlled. > All this based on over 10 years of work with the Shera controller, > exclusively controlling Rb's. > Bert Kehren > One more thought you may want to look at a 1 $ gate array for all your > timing issues. Simplifies the work dramatically. With the long loop times > associated with Rb and high sample rate, 100 psec. are no problem. > > > Name: Shera 3 board.pcb >Shera 3 board.pcbType: PCB Wizard Document > (application/x-unknown-content-type-PCBWizard.Document) > Encoding: base64 > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPSDO Alternatives
Chris, If you want to understand how to approach the issue, you need to study the Shera controller system. It does exactly what you and others are discussing doing. It is relatively simple, straight forward and the HEX file is available to program the CPU with. The circuit board is all ready made and available. The only hard part is the D/A which may be a bit of a problem with respect to the original part. However, even that may be available from another vender. If not there are some similar replacements, but that may require making new boards to account for the parts being surface mount types. Do yourself a favor and look at the following URL and download the reprint of the QST article. http://www.rt66.com/~shera/index_fs.htm BillWB6BNQ Chris Albertson wrote: > Now you can see the problem with designs that require both a PCB and a > programmed uP. Most people can't do either of these and those who can > typically are good at only one. Then you find someone and after he looses > interest the project is dead and un-suportable. > > So I was thinking of how to build a GPSDO that does not need a programmed > uP and would be so simple that a PCB would not be needed. It shoud be > simple enough that after getting the parts could be built quickly by anyone. > > The Arduino has a USB interface and both ADC and DAC and digital IO. I > read about the concern about using USB power. The Arduino can also be > powered by a 9V battery so it will continue to run if the USB power goes > away. Or you can use a power cube (aka "wall wort") Anyone can program an > Arduino even if you know nothing about uP. It is VERY easy and the > software runs on Mac OS X, Linux and even Windows. > > I would use a separate power supply for the OCXO as they take more power > and this needs to be cleaner than I'd expect USB power to be. > > The question I have again is about a simple phase detector. > > On Wed, Dec 5, 2012 at 3:28 AM, wrote: > > > Chris > > There is a low cost solution and I have the input circuit perfect for GPS > > on a $1 gate array I have boards and am presently using Shera original > > version. Would like to buy his version 402NE but have not been able to > > get a > > response from him. Have repeatedly asked for help on this list for some > > one to > > step forward to write the uproc. program. No one. The total material cost > > would be less than $ 25 PCB included GPS receiver OCXO or RB would be > > extra. If the FE 5680A with RS232 would be used cost is less than $ 15. > > There > > are now PIC's out there that can also do the timing function reducing cost > > even more but that will take more smarts. > > Bert Kehren > > > > > Chris Albertson > Redondo Beach, California > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WWVB new modulation
Hal, It is worse than that ! John P Lowe, Broadcast Manager for NIST, stated to me that "HE" was the person who invented the new modulation scheme. If that is the case then it belongs to all of us. AND that is, precisely, why they are publishing this modulation scheme. What I find interesting is this private company started up while JP Lowe was "inventing" this modulation scheme and requesting patents at the same time. Does the word COLLUSION come to mind ? Yet JP lowe claims he has no stake or interest in this new company. WELL, I am having a hard time with that very point. Equally interesting is that no public input was sought prior to considering this modulation scheme. Why is that you ask ? Most likely because everyone that actually uses 60 KHz for what it was intended for would be raising hell about it. What about the public ? This new scheme is suppose to allow for additional services. What could you possibly add that would be of advantage that is not available in a number of easier methods like AM/FM radio and TV for disseminating information. This, of course, completely ignores the Internet. As it is now, the public buys WWVB clocks because they really believe the damn thing is accurate, which it is truly not. So, to cut down on the controversy, they wait till they are ready to do it and then just spring on us like it is a done deal. As most people are rather passive in nature, they knew no major negative fallout would occur. Fallout being like a large group of people petitioning their representatives against it and so forth. Making it worse is the fact that all the major time and frequency companies abandoned their 60 KHz equipment line in favor of GPS. Sure GPS is better than 60 KHz, but one of these days something is going to f**kup the GPS system enough to cause problems. They already got rid of LORAN and they will probably find a way to get rid VOR, so flying will become an "F" ticket ride. This modulation scheme is just another blunder, not unlike Lightsquared, manipulating the public TEAT to pay for it. Oh, just my two cents, BillWB6BNQ Hal Murray wrote: > jim...@earthlink.net said: > > Actually, I think the developing company does have patents on some of the > > receiver implementations. You can probably design around them. > > What's the fine print in this area? Does NIST have any PR blurbs covering > patents? > > Common sense, politics, and patents makes for a horrible mess. > > I think I'd be happy if the developing company got a head start. That could > be a reasonable trade for a lot of engineering/support during testing. > > I think I'd be unhappy if they got a patent on a receiving technique that was > obvious to one skilled in the art (or whatever the magic patent phrase is) > after you looked at the description of the modulation/encoding technique. > That's assuming that NIST didn't get a broad free-to-use license for that > patent for listening to WWVB. > > Another way to view this mess is the general topic of patents in standards. > WWVB isn't in the same class of "standards" as IETF/IEEE/ANSI/ISO type > documents, but given that it's a government monopoly, it's as good (or > better) than any other standard. > > -- > These are my opinions. I hate spam. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Measuring gpsdo vs itself
Hi Tom, I think you missed the point. He is trying to measure the noise floor of the counter itself. So what he wants to know is if using the same signal for the time base and input, would that cancel out the signals contribution to the noise measurement. BillWB6BNQ Tom Van Baak wrote: > Bill, > > This is usually a good idea, since the counter then has both a good short- > and long-term stable/accurate timebase, inherited from the GPSDO. It means > the internal timebase of the counter is no longer a factor in measurement > stability or accuracy. There are exceptions to this, but I'll guess your > setup is not one of them. This configuration is especially good for 1PPS TI > measurements since it means a short 100 ns TI measurement is just as accurate > as a long 0.99900 s measurement. > > I'm not sure I'd call this a "reference independent" system; it's simply > using a GPSDO as the reference instead of the internal XO timebase of the > counter. > > /tvb > > - Original Message - > From: "Bill Dailey" > To: "Time Nuts" > Sent: Sunday, November 04, 2012 7:19 PM > Subject: [time-nuts] Measuring gpsdo vs itself > > > If I use a gpsdo as my reference and feed the same 10MHz into a counter > > does that yield the reference independent noise floor of the measuring > > system? Seems to me it would look like an ideal reference with respect to > > the measuring system. Thanks, > > > > Doc > > KX0O > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Rubidium as radio reference
Joseph Gray wrote:
Internet is flaky lately. I'll be brief, as I'm sending this from my
phone.
I don't need timenut accuracy for this. I want to make a setup for
measuring off the air, so local amateurs can have some way to check
a radio.
Using a service monitor, I can get a linear AC voltage from the
discriminator that corresponds to deviation. I can also measure a DC
noise squelch voltage that is inversely proportional to RSS, but not
linear. For carrier error, I get about 3V DC at the discriminator
for on frequency. Then I get a linear relationship for off
frequency.
I still need to figure out how to measure these voltages with an ADC
and interface to a R-Pi.
Just a fun project, I thought.
Joe Gray
W5JG
On Nov 4, 2012 4:15 PM, "WB6BNQ" <[1]wb6...@cox.net> wrote:
Hi Joe,
The reference oscillator is only part of the story. Being a typical
"FM" radio
the normal method is to observe when the carrier is in the center of
the
discriminator's bandpass. The particular center point is not a
constant, per se,
because the discriminator is typically adjusted so that the swing of
the
modulation is symmetrical and that is not usually at the exact
center. The
discriminator itself may not be symmetrical and often times the
center is skewed
because of it. Therefore you cannot necessarily rely on the center
point as
being "on" frequency. In addition to the so-called reference
frequency, you
would also have to stabilize the oscillators that feed the mixers if
there is
more than one IF frequency involved, which is usually the case.
The typical stability of these types of radios are pretty good but
no where near
time-nuts type stuff. When transmitting, the heat build up inside
the radio will
alter the transmit frequency by a few hertz to as much as few 100
hertz depending
upon the particular radio. This is normal and usually does not
affect the
ability to communicate due to the wide bandwidth of both the IF's
and the
discriminator. At the receiving end you can watch such action in
real time over
the length of the transmission.
If you are really trying to do something more in line with timenuts
type stuff,
you will, most likely, need to do a different approach. Perhaps you
could give
more details allowing for a better run of suggestions.
As for the FE-5680 Rb, it would require some filtering and such.
Instead of
trying to modify the radio for a direct feed from the Rb it would
serve you
better as a source in a PLL type arrangement.
Just my two cents. So give us more details.
BillWB6BNQ
Joseph Gray wrote:
> I know that some here are Amateurs and have used external sources
to
> provide a more accurate reference for a receiver. So, I have a
noob
> question or two.
>
> Is the programmable FE-5680A suitable to replace the 12.8 MHz
> reference in a Midland XTR? If so, where do I feed the rubidium
into
> the circuit (see attached screen clip)? X101 is the 12.8 MHz
crystal
> and R107 is used for temperature compensation.
>
> What I have in mind is to use the XTR radio for measuring
off-the-air
> carrier frequency error. It's just part of a project that I've
been
> thinking of doing. Things are still in the planning and
experimenting
> stage.
>
> Joe Gray
> W5JG
>
>
> Name: ScreenClip.png
>ScreenClip.pngType: PNG Image (image/png)
> Encoding: base64
>
>
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References
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Re: [time-nuts] Rubidium as radio reference
Hi Joe, The reference oscillator is only part of the story. Being a typical "FM" radio the normal method is to observe when the carrier is in the center of the discriminator's bandpass. The particular center point is not a constant, per se, because the discriminator is typically adjusted so that the swing of the modulation is symmetrical and that is not usually at the exact center. The discriminator itself may not be symmetrical and often times the center is skewed because of it. Therefore you cannot necessarily rely on the center point as being "on" frequency. In addition to the so-called reference frequency, you would also have to stabilize the oscillators that feed the mixers if there is more than one IF frequency involved, which is usually the case. The typical stability of these types of radios are pretty good but no where near time-nuts type stuff. When transmitting, the heat build up inside the radio will alter the transmit frequency by a few hertz to as much as few 100 hertz depending upon the particular radio. This is normal and usually does not affect the ability to communicate due to the wide bandwidth of both the IF's and the discriminator. At the receiving end you can watch such action in real time over the length of the transmission. If you are really trying to do something more in line with timenuts type stuff, you will, most likely, need to do a different approach. Perhaps you could give more details allowing for a better run of suggestions. As for the FE-5680 Rb, it would require some filtering and such. Instead of trying to modify the radio for a direct feed from the Rb it would serve you better as a source in a PLL type arrangement. Just my two cents. So give us more details. BillWB6BNQ Joseph Gray wrote: > I know that some here are Amateurs and have used external sources to > provide a more accurate reference for a receiver. So, I have a noob > question or two. > > Is the programmable FE-5680A suitable to replace the 12.8 MHz > reference in a Midland XTR? If so, where do I feed the rubidium into > the circuit (see attached screen clip)? X101 is the 12.8 MHz crystal > and R107 is used for temperature compensation. > > What I have in mind is to use the XTR radio for measuring off-the-air > carrier frequency error. It's just part of a project that I've been > thinking of doing. Things are still in the planning and experimenting > stage. > > Joe Gray > W5JG > > > Name: ScreenClip.png >ScreenClip.pngType: PNG Image (image/png) > Encoding: base64 > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Accurate timestamping on computers (previously: For mywhole life timezones have been weird)
Sarah, I am having a hard time understanding your problem. Or at least what you see as a problem. I am not sure what you are really complaining about here ? Is it the daylight change ? Or is it a dual boot problem which would suggest you do not have some settings in their rightful place ? The computer is merely displaying a form of time representation on the screen (human device). Internally, it seems to me, the computer's operating system is merely keeping a count of the passing seconds since reading the actual hardware, hardwired clock chip upon boot-up. After the initial boot it no longer reads the hardware clock chip to my understanding. If that is the case, it would suggest that a flag is recorded as to the daylight savings time change either in firmware or perhaps on the mass storage device that has the operating system. It is possible that the hardwired clock chip may keep track of the daylight savings function. If that is the case, perhaps the way to deal with it is to write a a small program that will make sure that hardwired chip stays in the NON daylight mode as part of a boot-up routine. As for the microsoft reference, it suggests not using a particular registry entry and if it is there to delete it. On my computer it is not present in the registry. While that only fixes some kind of system unresponsiveness issue, it does not seem to keep the daylight function from changing. With all the clock Synching available via the internet, it seems to me your clock should not be an issue in of itself. However, I am retired, as such, do not have a watch and pay little attention to the wall clock. BillWB6BNQ Sarah White wrote: > On 11/3/2012 5:32 AM, Sarah White wrote: > > So, at or around 1981 (the year I was born) there was a cool concept. > > IBM was selling "personal computers" (IBM-PC compatible later became a > > thing) and by the time I was old enough to operate a modem, I had one > > myself. Life was good. > > > > Wonder if there is any sensible way to petition microsoft to fix this > > stupid mistake dating back to the DOS era. Windows 8 / metro is out now, > > and I can't bloody stand the changes. Would be nice if windows 7 had an > > update to fix this issue: > > > > http://support.microsoft.com/kb/2687252 > > > > Article ID: 2687252 - Last Review: March 13, 2012 - Revision: 4.0 > > > > APPLIES TO > > Microsoft Windows XP Home Edition > > Microsoft Windows XP Professional > > Microsoft Windows XP Service Pack 3 > > Windows Vista Business > > Windows Vista Enterprise > > Windows Vista Home Premium > > Windows Vista Ultimate > > Windows Vista Service Pack 1 > > Windows Vista Service Pack 2 > > Windows 7 Enterprise > > Windows 7 Home Basic > > Windows 7 Home Premium > > Windows 7 Professional > > Windows 7 Ultimate > > Windows 7 Service Pack 1 > > Windows Server 2008 Datacenter > > Windows Server 2008 Enterprise > > Windows Server 2008 Standard > > Windows Server 2008 Service Pack 2 > > Windows Server 2008 R2 Datacenter > > Windows Server 2008 R2 Enterprise > > Windows Server 2008 R2 Standard > > Windows Server 2008 R2 Service Pack 1 > > Microsoft Windows Server 2003 Service Pack 2 > > > > ... Pretty sure that's 100% of all recent versions of windows. The whole > > thing started because windows 3.1 / 95 / 98 / 2000 / ME / etc. etc. etc. > > were all targeted with being backward compatible with the previous OS > > leading all the way back to DOS (first versions of DOS were coming out > > in 1981 the year I was born) > > > > For where I live, this weekend is the "change your clocks" for the > > fall... or don't, or do something else... petition microsoft maybe? > > > > I'd love for windows 7 to have a fix for this since I'm not upgrading to > > the horrible looking windows 8 --- windows 7 will be in extended support > > until 2020 (( reference: http://goo.gl/unxvj )) so I figure let's try to > > get them to fix it in the next few years. I'm serious about this. > > > > Let's fix this timezone problem!!! > > > > Pretty much every other operating system vendor out there (various POSIX > > platforms including more than one version of BSD, linux and even mac OSX > > since under the hood it is a POSIX based operating system) it is an > > option to leave the hardeware real-time-clock (bios clock) on UTC. > > > > Ok that's all I'm typing on this. > > > > Angry at several of my clocks today, > > Sarah White > > > > There are a number of reasons it can be problematic for an OS to change > the hardware clo
Re: [time-nuts] Efratom FRK and M100 question
Hi Corby, Will it start when it gets cold ? How long do you have to let it cool before it will re ignite ? Perhaps the lamp oscillator has a problem where it will not oscillate when hot with the momentary lost of power. BillWB6BNQ cdel...@juno.com wrote: > It's been a few years since I really dug into the FRK and M100 but I do > remember this particular common problem. > You power the unit up and after the normal warm up period it locks and > stays locked. > Then if you cycle the power the Lamp refuses to light. > Has anyone figured out the most likely cause of this symptom. > Any suggestions welcome! > > Thanks, > > Corby > > Woman is 53 But Looks 25 > Mom reveals 1 simple wrinkle trick that has angered doctors... > http://thirdpartyoffers.juno.com/TGL3141/5081eecf5c0326ecf24d3st04duc > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] WWVB Format Ownership
The transmitted format on WWVB (and for that matter on the WWV HF stations) is owned by the government and thus the "PEOPLE." As stated to me, John Lowe (WWVB Broadcast Manager) claims he is the person who has designed and is implementing this new broadcast format. Because he is a paid employee of the government (i.e., us PEOPLE) his new protocol is thus, presumably, unencumbered and free to use by anyone. What I find interesting is how a functional system is completely shit canned in favor of a new and yet proven process; particularly seeing as how no means of utilizing said new (and still being tweaked) modulation existed at the beginning of the design process. Obviously, the process was driven by external forces for the total benefit of those external forces. In other words, the benefit was not for "we the people" per se even though that is the stated reason. Conceptually, what Xtendwave seems to be doing is designing a "detection & demodulation" process that they feel is unique and thus eligible for a patent. If that is the whole truth and nothing but the truth, then more power to them. However, if they are attempting to construct their patent verbiage to exclude others from creating or using any other means and thus having sole use of the WWVB format, then one should question the propriety of the whole process including the WWVB staff. If the previous paragraph is the aim, then it is a parallel to a certain medical program where non participation is met with a hefty penalty. Here the hefty penalty would be having to buy the Xtendwave receiving apparatus in order to use said modulation process. Xtendwave would be hard pressed to go after all the "John Doe" hobbyists from both a monetary and political point of view. In the commercial market that would be a different case. Someone on the list posed the question of a "Public" comment period. YES, that would have been nice. BUT, such an action would have been disastrous for the project, if it really made a difference, because those who would bother to respond would likely be negative to the concept. That certainly wouldn't do, so instead it is done in quasi secret and sprung on the unsuspecting as a done deal. Clearly, DO IT and ask for forgiveness afterwards. So much for government transparency ! BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
