Re: [time-nuts] E4437B phase noise spurs. Any ideas?
Hi, Wolfgang. Both of your generators appear to be well within their datasheet specifications based on the spectrums you posted. The datasheet for that ESG-DP (digital modulation with high spectral purity) model is at: http://cp.literature.agilent.com/litweb/pdf/5965-3096E.pdf The E4437B nonharmonic spur specification is on page 5 (use the ESG- DP columns): So according to that table, above 2 GHz the E4437B spurs at 3 kHz offset **should be below -68 dBc**. It appears to me that the largest spur at such offsets (at about +3.5 kHz offset from the carrier) is **actually about -74 dBc**. The largest spur is about -63 dBc at +1 kHz offset (which is closer than the spur specs). The RS SMIQ03B specs are: The SMIQ03B nearby spurs in your screen capture are at about +/- 9 kHz offset from the carrier (about -85 dBc), so are too close to be covered by the spec above. The spurs at 10 kHz offset are about -90 dBc. I'm guessing that the spurs might be affected by several adjustments performed during factory alignment. In most modern complex instruments (including both of these signal generators, I believe) there are far too many alignments to be made by a human, and a long automated process using a rack of equipment is used to align the instrument and store certain constants in nonvolatile memory in the instrument. But there is no reason to worry based on your results, since they are well within instrument specifications. So ... assuming that the spurs aren't coming from your spectrum analyzer or other sources (and I'm guessing that's a FSU which is very good), both generators appear to be within specifications (after warmup within the calibration interval, of course). * *The E4437B closest spur covered by the 3 kHz spec is at about +3.5 kHz, and it's about 6 dB better than the spec.* * The SMIQ03B has a 6 dB better spurious spec than the E4437B between 2 and 3 GHz, but the SMIQ offset for their spur spec is wider than the ESG (10 kHz rather than 3 kHz). * At other carrier frequencies the spurs may be higher or lower in amplitude (and at different offsets). Try tuning the frequency in 1 kHz steps over a wide range -- I would guess that the spur offsets and levels will change in a complex fashion due to the synthesizer. * The phase noise specifications normally apply to a smoothed trace and do not include narrowband spurs such as the ones you see in your screen capture. -- Bill Byrom N5BB Tektronix RF Application Engineer On Thu, Jul 16, 2015, at 04:15 AM, Wolfgang DL1SKY wrote: Hi, I just got a used/refurbished E4437B which I wanted to use as a all-purpose RF generator primarily for 3-4 GHz. Unfortunately, I'm seeing strange spurs for frequencies above 2.4 GHz, see the green curve in the attached image. The yellow curve is an SMIQ03 for comparison. Observations: - For frequencies below 2.4 GHz none of the spurs appear. - It has an OCXO and I left the device in standby (oven on) for 12 hours. - If I leave the device ON for 1-2 hours, the spurs go down. Anybody else seeing this? Any ideas how to fix this? Does this look like a pre-failure sign? Regards, Wolfgang DL1SKY _ 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. Email had 1 attachment: * E4437B-phase_noise_problem-1.png 34k (image/png) ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
Hi Ole, Many thanks, 2.21 Ohm sounds more reasonable than 2 ZettaOhm (or 2 ZO), which is what 2E21 would translate into if it where 2*10^21, so I wanted to make sure there wasn't a typo. :) Then I know that my values may vary for that part of the design. Cheers, Magnus On 07/16/2015 09:21 PM, Ole Stender Nielsen wrote: Hi Magnus, The 2E21 is a 2.21 Ohms resistor. The RC network was found useful to ensure loading at higher frequencies. Best regards Ole Den 16-07-2015 kl. 18:27 skrev Magnus Danielson: Ole, What is the value of the 2E21 resistor? Looks like a typo. 2k? Feel inspired to rig up something for my FS700. Will wooden frame my TP-cable wired to form a 8 turns times the cable-turns. Cheers, Magnus On 07/16/2015 09:05 AM, Ole Stender Nielsen wrote: I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 insulated wire on a 80 x 80 cm wooden frame, and with a grounded base pre-amplifier mounted on the antenna frame. A schematic is enclosed for you to copy. The pre-amplifier is powered through the cable, and loads the FS700 input as required. I live about 290 km from the island of Sylt, and get nice noise margin figures from the FS700, normally about 40 dB, often up to 46 dB. For larger distances to the transmitter site, you may need to insert additional amplification between the grounded base pre-amplifier and the FS700, and that requires that you provide power to the pre-amplifier through a bias Tee, and that you load the FS700 input to keep it happy. A while after I installed the antenna in the attic, I added additional amplification, not due to a low signal level, but because I wanted to use the loop antenna for other longwave services too, and that required that I had to split out the signal. Best regards Ole Den 15-07-2015 kl. 18:02 skrev Dr. David Kirkby - Kirkby Microwave Ltd : Does anyone know of the latest firmware for the Stanford Research FS700 Loran-C frequency standard? I know someone who has one with firmware 1.20, but I don't know if there's any later firmware. I recall asking Stanford Research about firmware for the SR620 but got no response, so I don't know if I will have any better luck with the FS700. What's the best sort of antenna for these? I know Stanford sell one, and by the cost of new professional equipment, the $250 is not abnormally high, but I'd rather look at building something if I purchase one of these standards. I did think of using a half-wave dipole, but my garden is just a wee bit too small.:-) 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. ___ 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] 10MHz Square to Sine Wave Conversion
I was thinking along these lines. Cooking up a 3-pole filter in the form of a Pi-filter should be a good start, and then add traps for third and possibly fifth overtones that will not get much damping initially can be done if you need it pretty clean. Cheers, Magnus On 07/17/2015 04:07 AM, Graham / KE9H wrote: All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. ___ 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 Square to Sine Wave Conversion
For the life of me I can't find the link to the schematic or any mention of it in the archives. Google fail. However, I was able to find some screen shots and pictures from the Chebyshev filter that I built from the docs that I originally found here. This should get you started if you want to roll your own. Mini-Circuits makes a filter if memory serves, but this is a very cheap and fun project if you already have a little project box. Screen shots show simulation and most importantly, the values of the parts in the project. The 0.06uH inductor was hand wound and tweaked till I got it right. S parameters were measured with the cover ON and the cover does de-tune the circuit so you have to compensate before buttoning it up. https://goo.gl/photos/UiqRrFRNYczvcbNh6 -Bob N3XKB On Thu, Jul 16, 2015 at 11:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
You can't use the square wave? You could put in a resonant circuit that will select the fundamental but other issues arise, such as phase noise and harmonic content. How much harmonic content can you tolerate? There is a host of ways to do this job but much depends on your requirements. Bob K6DDX On Thursday, July 16, 2015 2:03 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
Hi, What distortion level would you like to achieve? Regards, Vasco Soares Em 2015-07-16 18:49, skipp Isaham via time-nuts escreveu: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
Here's the URL to the document I was referring to: http://www.w1ghz.org/small_proj/10MHz_Filter_for_GPS_Reference.zip And I see in my simulation I have the inductor and cap in the center of the schematic reversed, however it was built properly. -Bob On Thu, Jul 16, 2015 at 3:24 PM, Bob Darlington rdarling...@gmail.com wrote: For the life of me I can't find the link to the schematic or any mention of it in the archives. Google fail. However, I was able to find some screen shots and pictures from the Chebyshev filter that I built from the docs that I originally found here. This should get you started if you want to roll your own. Mini-Circuits makes a filter if memory serves, but this is a very cheap and fun project if you already have a little project box. Screen shots show simulation and most importantly, the values of the parts in the project. The 0.06uH inductor was hand wound and tweaked till I got it right. S parameters were measured with the cover ON and the cover does de-tune the circuit so you have to compensate before buttoning it up. https://goo.gl/photos/UiqRrFRNYczvcbNh6 -Bob N3XKB On Thu, Jul 16, 2015 at 11:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
How good does the sine wave need to be? The usual method is to use a low-pass filter A CLC pi filter works. On Thu, Jul 16, 2015 at 10:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. -- 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
Hi The simple approach is to buffer it with a few ‘125 buffers in parallel. Then convert to sine wave with a T-network matching section. There are a lot of matching calculators on the web. Something in the 50 to 200 ohm input range and 50 ohm output is a reasonable way to go. More gates and higher power = more output. Lower input impedance = more output. Bob On Jul 16, 2015, at 1:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] Trimble P/N 28367-00 Antenna Info
Very old GPS antenna (1997), from the Trimble SVeeSix receiver era. SO, it requires +5 VDC for power (pre-amp). ftp://ftp.trimble.com/pub/sct/embedded/bin/Manuals/Cm3/cm3_510_man.pdf Look at the SVeeSix manual (1997) and you will note, on page 1-5, that this magnetic mount antenna was packaged in the receiver's kit model. - Trying to help a friend with a ublox using an external antenna. Does any one know what the voltage range on this antenna is. Trimble P/N 28367-00 Thank you Bert Kehren Sent from iPad Air ___ 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 Square to Sine Wave Conversion
Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. -- -- Teach your kids Science, or somebody else will :/ ja...@ball.net vk2...@google.com vk2f...@google.com callsign: vk2vjb ___ 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 Square to Sine Wave Conversion
Hi Skipp, I suggest you a simple passive filter with harmonic notch as this: http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf Obviously you have to made the 10MHz version, Ciao, Luciano On Thu 16/07/15 19:49 , skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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 Square to Sine Wave Conversion
Skipp wrote: The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions A simple Tee network works well (see below). The input resistor can be chosen from 50 to around 200 ohms to suit the particular output circuit used in your unit. As the value is reduced, the sine wave output will increase (until you hit the current limit of the GPSDO output stage). Use the lowest value that still gives good distortion performance. If the sinewave output amplitude is too large, increase the input resistor. If the sinewave output amplitude is too small, you can either add a linear amplifier after the filter, or run the square wave from the GPSDO into several high-current CMOS gates in parallel and then through the Tee network (in that case, you would use one input resistor from each of the output gates rather than tie the gate outputs directly to each other). 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] 5 x 2 x 3 = 30 MHz
I am working with this .. amazing device, Ulrich N1UL ___ 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] Ublox LEA-6T CFG-PRT command question
Bob, My experience is with the LEA-5T but I am confident that the same applies to your the LEA-6T. My recommendation is to make the changes with the USB interface and the U-center software (available at no charge, download UBLOX). If the interface is not provided for it is as simple as a usb cable two 22ohm resistors and a 3.3V regulator and the appropriate capacitors. Need further help let me know, I'll provide additional details. Another way I have done it is to remove the chip which normally talks to the GPS via the serial path and insert the appropriate serial converter board temperarily, usually only three connections (Rx, Tx, GND) and again use the u-center software. -- S. Cash Olsen KD5SSJ ARRL Technical Specialist Message: 15 Date: Thu, 16 Jul 2015 23:07:49 + (UTC) From: Bob Stewart b...@evoria.net To: Discussion of Precise Time and Frequency Measurement time-nuts@febo.com Subject: [time-nuts] Ublox LEA-6T CFG-PRT command question Message-ID: 153560478.2529422.1437088069308.javamail.ya...@mail.yahoo.com Content-Type: text/plain; charset=UTF-8 I want to change the UART1 port speed on my LEA-6T via message string from my GPSDO board. I had assumed that I would have to discover (or know) the baud rate already set on the LEA-6T in order to change it. But it appears that the LEA-6T can receive messages at any baud rate, but you need to send baud rate change commands at the baud rate you wish to change it to. Can anyone verify if this is the case? I can't find anything in the documentation I have that addresses this question. Maybe it's just obvious to everyone else? 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.
Re: [time-nuts] Ublox LEA-6T CFG-PRT command question
On Thu, 16 Jul 2015 23:07:49 + (UTC) Bob Stewart b...@evoria.net wrote: I want to change the UART1 port speed on my LEA-6T via message string from my GPSDO board. I had assumed that I would have to discover (or know) the baud rate already set on the LEA-6T in order to change it. But it appears that the LEA-6T can receive messages at any baud rate, but you need to send baud rate change commands at the baud rate you wish to change it to. Can anyone verify if this is the case? I can't find anything in the documentation I have that addresses this question. Maybe it's just obvious to everyone else? Have you tried to send that question to the u-blox support? They would be the right ones to answer it (and properly document it). If you don't get an anwswer within a reasonable time (let's say a week or two) please let me know. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] Belated leap second video / result
Here's a video of my Spectracom 9183 and my homebuilt GPS/Rb NTP server both cruising through last month's leap second (the first one in my new lab) without incident. Apologies for the blur/bloom on the laptop screen, I guess I didn't get the focus exactly right. You can still read it as long as you already know what you're looking for :) https://vimeo.com/133728097 Leap second is at 1:09 in the video, both devices display 23:59:60 UTC. A second later, both display 00:00:00 and the LEAP (upcoming leap second) indicator on my GPS clock cleared. A few minutes later, I checked NTP sync and both of my Linux boxes also adjusted correctly (this time without any kernel bugs) and were within 1ms of the NTP clock. Andrew ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
On Fri, 17 Jul 2015 10:03:00 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: Many thanks, 2.21 Ohm sounds more reasonable than 2 ZettaOhm (or 2 ZO), which is what 2E21 would translate into if it where 2*10^21, so I wanted to make sure there wasn't a typo. :) xEy is some kind of semi-standard notation for resistor values in the first three decades, when people do not want to write R (as it might be confused with the part number) or a dot (which might get lost when printing). But I don't know where this notation came from, or what the E stands for. I can only say I have seen it quite a few times already. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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 Square to Sine Wave Conversion
Hi If you run a filter with a shunt capacitor input (as opposed to the series L proposed by Charles, the current in the driving gate goes way up. It’s driving a short at the harmonic frequencies and it does not like this. If you want more power with a simple T, just run the T. No resistor at the input or output. You can get 18 dbm this way. A single gate providing 18 dbm probably will not last very long. A gate in a “3.3V only” family may not be happy with the ringing on the filter input. This of course begs the question - do you *need* more than 18 dbm? Bob On Jul 16, 2015, at 11:10 PM, D W watsondani...@gmail.com wrote: Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan image2.png On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. ___ 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 Square to Sine Wave Conversion
Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob On Jul 17, 2015, at 4:07 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: I was thinking along these lines. Cooking up a 3-pole filter in the form of a Pi-filter should be a good start, and then add traps for third and possibly fifth overtones that will not get much damping initially can be done if you need it pretty clean. Cheers, Magnus On 07/17/2015 04:07 AM, Graham / KE9H wrote: All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. ___ 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] 10MHz Square to Sine Wave Conversion
I have a Mini-Circuits BLP-10.7 that I picked up at a Flea Market that does the job. And no, I do not want to sell it !! 73, Dick, W1KSZ On 7/16/2015 10:47 PM, Jason Ball wrote: A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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] 10MHz Square to Sine Wave Conversion
It is the simplest solution because you have not to tune the notch filter but you have -20dB on 2nd harmonic and -40dB for the third instead -50dB (min for both) if you made a low-pass with notch filters. Luciano On Fri 17/07/15 05:10 , D W watsondani...@gmail.com wrote: Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] 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 [2] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts[2] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
On 16 July 2015 at 08:05, Ole Stender Nielsen ols...@mail.tele.dk wrote: I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 insulated wire on a 80 x 80 cm wooden frame, and with a grounded base pre-amplifier mounted on the antenna frame. A schematic is enclosed for you to copy. Thank you. I will build one of those. I have most of the parts here, but not the transistors. The pre-amplifier is powered through the cable, and loads the FS700 input as required. I live about 290 km from the island of Sylt, and get nice noise margin figures from the FS700, normally about 40 dB, often up to 46 dB. It's odd that http://www.loran-history.info/sylt/sylt.htm shows Sylt as closing in 2006. Did Sylt ever close and then re-open, and that web site just out of date? I'm a little further than you (321 km vs your 290 km) from my nearest transmitter. I'm located in Althorne, Chelmsford, Essex, UK (51.6517913 N, 0.7752657 E) and I *believe* my nearest Loran-C transmitters are 1) Lessay, France, power = 250 kW, distance = 321 km, bearing = 211 degrees. 2) Anthorn, England, power =- 250 kW, distance = 419 km, bearing 331 degrees. 3) Sylt, Germany, power = 250 kW, distance = 611 km, bearing = 52 degrees. 4) Soustons, France, power = 250 kW, distance = 896 km, bearing 191 degrees 5) Edja, Fraoe islands, power = 400 kW, distance = 1274 km, bearing = 341 degrees. For larger distances to the transmitter site, you may need to insert additional amplification between the grounded base pre-amplifier and the FS700, and that requires that you provide power to the pre-amplifier through a bias Tee, and that you load the FS700 input to keep it happy. A while after I installed the antenna in the attic, I added additional amplification, not due to a low signal level, but because I wanted to use the loop antenna for other longwave services too, and that required that I had to split out the signal. Best regards Ole Thank you Ole. That at least gives me something to start from. I guess the op-amp design Poul-Henning Kamp used offers more flexibility for gain adjustment. I might look at that too. If the amplifier is in a box with a couple of banana jacks and a BNC socket, it is fairly easy to change one amp for another. I assume from what you say that the FS700 will report the 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.
Re: [time-nuts] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
On 16 July 2015 at 23:23, Bob Camp kb...@n1k.org wrote: Hi Quick and simple: 1) Signal power is proportional to the area of the loop. Bigger is better. 2) Inductance is proportional to the turns squared. Turns do not directly affect signal to noise. 3) Inductance may be resonated with a capacitor. This gives a bandpass function. 4) The coil shapes are very common. The many inductance calculators on the web will give you an inductance estimate. 5) If the inductance is resonated, the system Q (and thus bandwidth) is a function of the coil losses and the amplifier’s input impedance. 6) More turns gives a power match into a higher impedance ( more voltage). 7) *Practical* matching of the amplifier to the antenna will give you an reasonable target number of turns. Bob It's interesting that http://www.vlf.it/feletti2/idealloop.html says that sensitivity is set by the mass of copper used. To quote A single turn square loop, 1m side, made with 1kg copper has the same sensitivity of a 1000 turns square loop made with 1kg copper and same dimensions. In this context, the sensitivity limit is represented only by loop thermal noise: noise floor (nV/sqrt(Hz)) = 4 sqrt(R in kOhm) It is not immediately obvious where that equation comes from, but re-arranging the equation for thermal noise power P=k T B (P in watts, k= Boltzmann contant, B is bandwidth in Hz) and assuming a temperature T of 300 Kelvin, k = 1.38 x 10^-23 J/K, one finds the constant is 4.06, so the 4 in that equation is fairly accurate at 300 Kelvin. I'd much rather wind a loop with a few turns than a few hundred turns! But obviously the voltage rises with the number of turns, so requires less gain. 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.
Re: [time-nuts] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
Hi On Jul 17, 2015, at 8:31 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 16 July 2015 at 23:23, Bob Camp kb...@n1k.org wrote: Hi Quick and simple: 1) Signal power is proportional to the area of the loop. Bigger is better. 2) Inductance is proportional to the turns squared. Turns do not directly affect signal to noise. 3) Inductance may be resonated with a capacitor. This gives a bandpass function. 4) The coil shapes are very common. The many inductance calculators on the web will give you an inductance estimate. 5) If the inductance is resonated, the system Q (and thus bandwidth) is a function of the coil losses and the amplifier’s input impedance. 6) More turns gives a power match into a higher impedance ( more voltage). 7) *Practical* matching of the amplifier to the antenna will give you an reasonable target number of turns. Bob It's interesting that http://www.vlf.it/feletti2/idealloop.html says that sensitivity is set by the mass of copper used. To quote A single turn square loop, 1m side, made with 1kg copper has the same sensitivity of a 1000 turns square loop made with 1kg copper and same dimensions. In this context, the sensitivity limit is represented only by loop thermal noise: The *power* into the loop is a function of the area. noise floor (nV/sqrt(Hz)) = 4 sqrt(R in kOhm) It is not immediately obvious where that equation comes from, but re-arranging the equation for thermal noise power P=k T B simply the standard thermal noise equation for a resistor (P in watts, k= Boltzmann contant, B is bandwidth in Hz) and assuming a temperature T of 300 Kelvin, k = 1.38 x 10^-23 J/K, one finds the constant is 4.06, so the 4 in that equation is fairly accurate at 300 Kelvin. I'd much rather wind a loop with a few turns than a few hundred turns! But obviously the voltage rises with the number of turns, so requires less gain. *but* the load resistance (and thus the thermal noose in that load) goes up at the same time. If you have a very low impedance buffer (common base stage etc) the number of turns will be very different than if you have the input gate of a MOSFET. Bob 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
I had not been paying attention to the thread but it has evolved into an area I had a question about. Typical LORAN C systems are the vlf preamp and whip. You never see anything about larger antennas such as might be used from the US to receive Europe stations. For WWVB 60 KHz I built a large loop 10' X 10' and 800' of wire tuned with preamp. The gain was dramatic to say the least. So I have been interested in building a large loop for LORAN C. But never really found any detail. From this thread it may be actually useful. I would build the same size loop but not make it sharply tuned because of the large signal bandwidth +- 10Khz. With the whip on winter nights I do get occasional lock of the European signals. Granted this will be an over the summer project. Regards Paul WB8TSL On Fri, Jul 17, 2015 at 8:31 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 16 July 2015 at 23:23, Bob Camp kb...@n1k.org wrote: Hi Quick and simple: 1) Signal power is proportional to the area of the loop. Bigger is better. 2) Inductance is proportional to the turns squared. Turns do not directly affect signal to noise. 3) Inductance may be resonated with a capacitor. This gives a bandpass function. 4) The coil shapes are very common. The many inductance calculators on the web will give you an inductance estimate. 5) If the inductance is resonated, the system Q (and thus bandwidth) is a function of the coil losses and the amplifier’s input impedance. 6) More turns gives a power match into a higher impedance ( more voltage). 7) *Practical* matching of the amplifier to the antenna will give you an reasonable target number of turns. Bob It's interesting that http://www.vlf.it/feletti2/idealloop.html says that sensitivity is set by the mass of copper used. To quote A single turn square loop, 1m side, made with 1kg copper has the same sensitivity of a 1000 turns square loop made with 1kg copper and same dimensions. In this context, the sensitivity limit is represented only by loop thermal noise: noise floor (nV/sqrt(Hz)) = 4 sqrt(R in kOhm) It is not immediately obvious where that equation comes from, but re-arranging the equation for thermal noise power P=k T B (P in watts, k= Boltzmann contant, B is bandwidth in Hz) and assuming a temperature T of 300 Kelvin, k = 1.38 x 10^-23 J/K, one finds the constant is 4.06, so the 4 in that equation is fairly accurate at 300 Kelvin. I'd much rather wind a loop with a few turns than a few hundred turns! But obviously the voltage rises with the number of turns, so requires less gain. 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.
[time-nuts] 5MHz Crystal Phase noise
Simulated 5 Mhz phase noise, only very little deviation from measured data. Happy weekend, Ulrich N1UL Greg2.docx Description: Binary data ___ 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 Square to Sine Wave Conversion
Charles Wenzel has very simple but good working solution, here is : http://www.wenzel.com/documents/waveform.html On 7/17/2015 8:20 AM, Richard Solomon wrote: I have a Mini-Circuits BLP-10.7 that I picked up at a Flea Market that does the job. And no, I do not want to sell it !! 73, Dick, W1KSZ On 7/16/2015 10:47 PM, Jason Ball wrote: A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. ___ 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] 5MHz Crystal Phase noise
Dear Ulrich, On 07/17/2015 01:15 PM, ka2...@aol.com wrote: Simulated 5 Mhz phase noise, only very little deviation from measured data. Happy weekend, Ulrich N1UL Looks like you did your homework well, which is expected. :) Would love to have more devices with that kind of phase-noise. MVH 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.
Re: [time-nuts] 5 x 2 x 3 = 30 MHz
Ulrich, Nice picture. What are you doing with the crystal? I have several older crystals that are nice but have never done anything with them. Regards Paul WB8TSL On Thu, Jul 16, 2015 at 6:02 PM, KA2WEU--- via time-nuts time-nuts@febo.com wrote: I am working with this .. amazing device, Ulrich N1UL ___ 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] 5 x 2 x 3 = 30 MHz
He doesn't mention that that crystal is used in New Horizons: http://www.bliley.com/products/crystals-precision-standard/vacuum-sealed/ Nice. I have a similar crystal from Valpey-Fischer, 5 MHz 5th overtone AT-cut (as opposed to your 3rd overtone SC-cut). I would be interested in what you would use for an oscillator circuit. David N1HAC On 7/17/15 4:27 PM, paul swed wrote: Ulrich, Nice picture. What are you doing with the crystal? I have several older crystals that are nice but have never done anything with them. Regards Paul WB8TSL On Thu, Jul 16, 2015 at 6:02 PM, KA2WEU--- via time-nuts time-nuts@febo.com wrote: I am working with this .. amazing device, Ulrich N1UL ___ 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] 5 x 2 x 3 = 30 MHz
Hi The basic space grade crystal is in the $400 to $1000 range (depends on quantity). After they do the 10:1 sort, the resulting ones are (effectively) $4K to $10K each. The cost just goes up from there.If you count in the labor, it probably adds another 30% to the cost. If you don’t do the sorts, the basic crystal is not (on average) much better than any other 5MHz unit with the same blank size. Yield through the whole process is dependent on the batch they get. It *may* be 10%. Bob On Jul 17, 2015, at 5:50 AM, tim...@timeok.it wrote: I an curious to know the price of this crystal. Luciano On Fri 17/07/15 00:02 , KA2WEU--- via time-nuts time-nuts@febo.com wrote: I am working with this .. amazing device, Ulrich N1UL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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 with ADEV of 1E-13 on Pluto Mission
This will keep you busy. Nice papers on space-qualified USO (ultra stable oscillators): Developments in Ultra-Stable Quartz Oscillators for Deep Space Reliability http://tycho.usno.navy.mil/ptti/2004papers/paper35.pdf An Ensemble of Ultra-Stable Quartz Oscillators to Improve Spacecraft Onboard Frequency Stability http://tycho.usno.navy.mil/ptti/2006papers/paper29.pdf The In-Flight Frequency Behavior of Two Ultra-Stable Oscillators Onboard the New Horizons Spacecraft http://tycho.usno.navy.mil/ptti/2007papers/paper7.pdf Enhancing the Art of Space Operations - Progress in JHU/APL Ultra-Stable Oscillator Capabilities http://tycho.usno.navy.mil/ptti/2008papers/paper6.pdf A Decade in Time: The Advancement of the APL Time and Frequency Laboratory http://techdigest.jhuapl.edu/TD/td3201/32_01-Miranian.pdf Ultra-Stable Oscillators For Probe Radio Science Investigations http://websites.isae.fr/IMG/pdf/uso-toulouse.pdf /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.
Re: [time-nuts] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
MAT12 of ADI is good replacement and it is available at Mouser http://www.mouser.com/Search/Refine.aspx?Keyword=MAT12 On 7/17/2015 1:49 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 16 July 2015 at 08:05, Ole Stender Nielsen ols...@mail.tele.dk wrote: I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 insulated wire on a 80 x 80 cm wooden frame, and with a grounded base pre-amplifier mounted on the antenna frame. A schematic is enclosed for you to copy. The pre-amplifier is powered through the cable, and loads the FS700 input as required. I live about 290 km from the island of Sylt, and get nice noise margin figures from the FS700, normally about 40 dB, often up to 46 dB. A couple of questions 1) Do you have any suggestions for a replacement for the LM394CN, which is obsolete and unobtainable from any reputable source? There are plenty on eBay for a few $'s from China, but the probability of them being fakes is greater than 0.99. The MAT12 seems to be one possible candidate for a replacement and while not cheap, is available from reputable sources like Farnell. 2) What is the Ca. 3 Ohm to the left of your circuit? Is that what you estimate the input impedance is? I've got 95 m of 2.5 mm^2 wire. The resistance of that is about 7.41 mOhm/m so my 95 m would have a DC resistance of around 7 Ohms if I used it all. I have built the loop 1.0 x 1.2 m. Hopefully that will be ok to receive at least one or both of * Lessay, France, power = 250 kW, distance = 321 km, bearing = 211 degrees. * Anthorn, England, power =- 250 kW, distance = 419 km, bearing 331 degrees. I now need to work out how many turns to put on it. 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] 5 x 2 x 3 = 30 MHz
Looks like an SC cut. Let me know if you have any questions about this. Jerry N9XR On Jul 17, 2015 6:35 PM, paul swed paulsw...@gmail.com wrote: Ulrich, Nice picture. What are you doing with the crystal? I have several older crystals that are nice but have never done anything with them. Regards Paul WB8TSL On Thu, Jul 16, 2015 at 6:02 PM, KA2WEU--- via time-nuts time-nuts@febo.com wrote: I am working with this .. amazing device, Ulrich N1UL ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
On Fri, 17 Jul 2015 21:49:01 +0100 Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: A couple of questions 1) Do you have any suggestions for a replacement for the LM394CN, which is obsolete and unobtainable from any reputable source? There are plenty on eBay for a few $'s from China, but the probability of them being fakes is greater than 0.99. The MAT12 seems to be one possible candidate for a replacement and while not cheap, is available from reputable sources like Farnell. The SSM2212 seems to be a quite compatible replamcement, with most parameters being in the same range. Cost ~6USD/pcs But i guess, for this application, the noise performance of the transistors is not that critical and something like a BCM847 should do the job as well. (cost 0.5USD/pcs) 2) What is the Ca. 3 Ohm to the left of your circuit? ca. = circa = approximately. Probably an abrevation that is only common around europe. Is that what you estimate the input impedance is? I've got 95 m of 2.5 mm^2 wire. The resistance of that is about 7.41 mOhm/m so my 95 m would have a DC resistance of around 7 Ohms if I used it all. Hmm.. I think the impedance matters more than the resistance. But the schematics does not make any reference to that. Consider me confused. Attila Kinali -- I must not become metastable. Metastability is the mind-killer. Metastability is the little-death that brings total obliteration. I will face my metastability. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the metastability has gone there will be nothing. Only I will remain. ___ 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 Square to Sine Wave Conversion
Hi The narrower the bandpass of the network, the more delay it will have. The more delay it has, the more phase shift you will have over temperature. With a “low Q” T network, the phase shift is pretty small. It is likely you will have as much shift in other parts of your system as in a Q = 1 match network. Bob On Jul 17, 2015, at 2:23 PM, Michael mikenet...@comcast.net wrote: Before I waste time simulating too much... Does anyone have any intuition around temperature dependence of these designs? Is one 'style' significantly better than another? I'm far more concerned about phase shift of the fundamental during temperature swings than I am relative harmonic levels/phase moving around. Michael Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob ___ 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] 10MHz Square to Sine Wave Conversion
Hi Ok, so one more vote for a gate driving a T network. Bob On Jul 17, 2015, at 2:21 PM, Alex Pummer a...@pcscons.com wrote: Charles Wenzel has very simple but good working solution, here is : http://www.wenzel.com/documents/waveform.html On 7/17/2015 8:20 AM, Richard Solomon wrote: I have a Mini-Circuits BLP-10.7 that I picked up at a Flea Market that does the job. And no, I do not want to sell it !! 73, Dick, W1KSZ On 7/16/2015 10:47 PM, Jason Ball wrote: A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. ___ 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] Firmware and antenna for Stanford Research FS700
Dave wrote: 1) Do you have any suggestions for a replacement for the LM394CN, which is obsolete and unobtainable from any reputable source? There are plenty on eBay for a few $'s from China, but the probability of them being fakes is greater than 0.99. The MAT12 seems to be one possible candidate for a replacement and while not cheap, is available from reputable sources like Farnell. The MAT12 should certainly work, but there is *plenty* of DC degeneration in the circuit (1v at each emitter), so there is no advantage to matched transistors. A pair of Zetex (Diodes, Inc.) ZTX849 or FZT849 actually have significantly lower voltage noise than either the LM394 or MAT12. 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
Bob, I intended nothing aiming for perfect. My initial proposal was actually for a 1 pole low-pass and then a block at 30 MHz for third overtone, but I never put that in mail-form. Cheers, Magnus On 07/17/2015 02:57 PM, Bob Camp wrote: Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob On Jul 17, 2015, at 4:07 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: I was thinking along these lines. Cooking up a 3-pole filter in the form of a Pi-filter should be a good start, and then add traps for third and possibly fifth overtones that will not get much damping initially can be done if you need it pretty clean. Cheers, Magnus On 07/17/2015 04:07 AM, Graham / KE9H wrote: All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
In message cad2jfahdfe1zqccukxfyeznnpa35qwp1cqpbgkptfmhs9fc...@mail.gmail.com , paul swed writes: So I have been interested in building a large loop for LORAN C. You cannot use a tuned/resonance loop for LORAN-C the way you can for CW stations like WWVB. Loran-C needs +/- 15kHz flat bandwidth (85-115 kHz) otherwise you loose the pulse-shape which allows you to find the right zero-crossing. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
On Fri, 17 Jul 2015 12:55:07 +0100 Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: Thank you Ole. That at least gives me something to start from. I guess the op-amp design Poul-Henning Kamp used offers more flexibility for gain adjustment. I might look at that too. If the amplifier is in a box with a couple of banana jacks and a BNC socket, it is fairly easy to change one amp for another. I assume from what you say that the FS700 will report the I would probably replace the AD797 with it's younger cusin the AD8099. The noise performance is very similar, but it has a GBW-product of 3GHz (instead of 110MHz), which potentially allows you do get much higher gain in the first stage. And best is: you can run it from a +5V supply and don't need to bother with a +/-5V supply (keeping in mind that the AD797 specs are for +/-15V, so they are likely to be worse at +/-5V). Please note that neither of those opamps are rail-to-rail. You need to stay 1.3V clear of the rails for the AD8099 (both, input and output) and 2.5V and 3V for input and output respectively for the AD797. The datasheet does not specify what happens when you cross the input rails limit, but I would expect nasty stuff like gain reversal and such. Also, the absolute maximum ratings have a maximum differential input voltage of 1.8V and 0.7V respectively. Do not cross that line, lest you want to smell magic smoke (ok, not really, but it might at least detoriate the input protection diodes, if not fry them) Attila Kinali -- I must not become metastable. Metastability is the mind-killer. Metastability is the little-death that brings total obliteration. I will face my metastability. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the metastability has gone there will be nothing. Only I will remain. ___ 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] 5 x 2 x 3 = 30 MHz
I an curious to know the price of this crystal. Luciano On Fri 17/07/15 00:02 , KA2WEU--- via time-nuts time-nuts@febo.com wrote: I am working with this .. amazing device, Ulrich N1UL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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 Square to Sine Wave Conversion
Before I waste time simulating too much... Does anyone have any intuition around temperature dependence of these designs? Is one 'style' significantly better than another? I'm far more concerned about phase shift of the fundamental during temperature swings than I am relative harmonic levels/phase moving around. Michael Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob ___ 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 Square to Sine Wave Conversion
Hi If you attach a filter with a shunt capacitor (capacitor to ground) at it’s input to the output of a logic gate, that gate will pull far more current than it would without a shunt capacitor being present. You can try to minimize this with a series resistor, but that’s only a partial fix. Bob On Jul 17, 2015, at 5:49 AM, tim...@timeok.it wrote: It is the simplest solution because you have not to tune the notch filter but you have -20dB on 2nd harmonic and -40dB for the third instead -50dB (min for both) if you made a low-pass with notch filters. Luciano On Fri 17/07/15 05:10 , D W watsondani...@gmail.com wrote: Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] 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 [2] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts[2] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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 with ADEV of 1E-13 on Pluto Mission
On Thu, 16 Jul 2015 15:24:08 -0400 Brian, WA1ZMS wa1...@att.net wrote: The crystal in the ref osv. came from Bliley. The part number is BG-61. I have no idea what the current cost is, but like most very good oscillators the crystals were hand sorted and graded. I had a short chat with Gregory Weaver (the guy behind the USO) two years ago. Basically, they start with a lot of crystal slabs, select the best ones after each processing step. In the end, they have maybe a dozen (or less) crystals that are then fit into oscillators, which again are tuned by hand and selected. The best oscillators are then send onto the mission. A fun fact here is, that the oscillators are not tuned for maximum Q of the resonator. Instead they are slightly damped and some Q is traded for lower noise of the sustaining amplifier. Another fun fact is, that the glass housing acts like a getter when put in vacuum. Thus the stability increases increases over time, when the whole system is in space. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] Commercial Wireless Precise Time Initiative - eLoran based
http://rntfnd.org/2015/07/16/new-initiative-commercially-owned-low-frequency -wireless-timing-navigation-based-on-eloran/ Dana A. Goward President Executive Director Resilient Navigation Timing Foundation dgow...@rntfnd.org mailto:dgow...@rntfnd.org 571-225-2580 (c) 888-354-9109 703-916-0336 (h) RNTFnd.org Helping Protect Critical Infrastructure for a Safer World - Educating the public and leaders about the importance of navigation and timing signals, as well as the need for resilience -Supporting stronger laws and better enforcement to combat jamming and spoofing -Supporting establishment of a strong, difficult-to-disrupt terrestrial signal to augment and be used alongside GNSS ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
On 16 July 2015 at 08:05, Ole Stender Nielsen ols...@mail.tele.dk wrote: I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 insulated wire on a 80 x 80 cm wooden frame, and with a grounded base pre-amplifier mounted on the antenna frame. A schematic is enclosed for you to copy. The pre-amplifier is powered through the cable, and loads the FS700 input as required. I live about 290 km from the island of Sylt, and get nice noise margin figures from the FS700, normally about 40 dB, often up to 46 dB. A couple of questions 1) Do you have any suggestions for a replacement for the LM394CN, which is obsolete and unobtainable from any reputable source? There are plenty on eBay for a few $'s from China, but the probability of them being fakes is greater than 0.99. The MAT12 seems to be one possible candidate for a replacement and while not cheap, is available from reputable sources like Farnell. 2) What is the Ca. 3 Ohm to the left of your circuit? Is that what you estimate the input impedance is? I've got 95 m of 2.5 mm^2 wire. The resistance of that is about 7.41 mOhm/m so my 95 m would have a DC resistance of around 7 Ohms if I used it all. I have built the loop 1.0 x 1.2 m. Hopefully that will be ok to receive at least one or both of * Lessay, France, power = 250 kW, distance = 321 km, bearing = 211 degrees. * Anthorn, England, power =- 250 kW, distance = 419 km, bearing 331 degrees. I now need to work out how many turns to put on it. 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.
Re: [time-nuts] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
In message 36e5f870-b2dd-42bb-a1d5-24d241aca...@n1k.org, Bob Camp writes: It's interesting that http://www.vlf.it/feletti2/idealloop.html says that sensitivity is set by the mass of copper used. To quote A single turn square loop, 1m side, made with 1kg copper has the same sensitivity of a 1000 turns square loop made with 1kg copper and same dimensions. In this context, the sensitivity limit is represented only by loop thermal noise: The *power* into the loop is a function of the area. I think they're barking up another tree: The number of turns you can make is inversely proportional to cross-section of the wire, so given a fixed mass of conductor, you can trade current for voltage by the number of turns. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
