Re: [time-nuts] FE-5680A Shipping question
I finally broke down and bought one too- mine took about 10 days to get to the west coast. -Dave - Original Message - From: paul swed paulsw...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, December 30, 2011 7:27:13 AM Subject: Re: [time-nuts] FE-5680A Shipping question Yes the free shipping by post is about 4 to 5 weeks. Regards Paul On Fri, Dec 30, 2011 at 10:24 AM, mike cook michael.c...@sfr.fr wrote: Mine was slow, but I expected it. 25/11-28/12. Le 30/12/2011 11:30, Rob Kimberley a écrit : I bought a couple of these on EBay recently. Would like to know from the group what the typical shipping times have been so far from China. Cheers Rob Kimberley __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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-nutshttps://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? (re simple gpsdo.)
PI controllers can be implemented analog only. For the PPS they need large capacitors that are the equivalent of averaging (sum and accumulate) in a software implemented controller. On Sat, Dec 31, 2011 at 7:54 AM, Chris Albertson albertson.ch...@gmail.comwrote: On Fri, Dec 30, 2011 at 11:46 AM, Stanley timen...@n4iqt.com wrote: What is the simplest design for a GPSDO that uses only the PPS signal from a modern GPS? Some sort of oscillator with a voltage control. CPU with a timer/counter that can capture the PPS. DAC. Software. How about MSC1200 : http://www.ti.com/lit/ds/symlink/msc1200y3.pdf I don't count anything with a computer and software inside as simple. My definition of a simple device is a capacitor or a transistor or I guess a single flip-flop or op-amp. A simple controller would some how use about two dozen or less of these kinds of components. Home heating thermostats can be simple of complex. Some use LCD displays and a computer. Other have a simple bimetallic spring inside. If this CAN'T be done. And if a computer is really required. I'm going to go all out and use a real computer. Something that can run an operating system and talk on the network. Here is an example of what I mean http://www.embeddedarm.com/products/board-detail.php?tab=optionsproduct=TS-7550# No one really wants a device that connects to a computer over a serial port. That was 20 years ago. The above board can host a web site and log data to a USB thumb drive and burns less then 2W of power But for now I'm looking for a controller that is much more like the bimetallic spring thermostat. 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] Thunderbolt? (re simple gpsdo.)
In my opinion you have to look at it from the point of application. Hopefully I will be able to share the test results soon. For us DNL is key, INL is specked over the full range and since we use it in a filter application, based on the data that I have, can be ignored. In a Rb application I use 1.5 E-14 steps with a total range of 1 E-9, with OCXO's the steps are 1.5 E-13 and rage 1 E-8. In some applications I use smaller step sizes on the OCXO at the expense of range. Some OCXO's aging allow using 1.5 E -14. Do not forget that step sizes are 61 uV and take that into consideration when you look at the temperature specs. I also use it in an environment where temperature is better than + - .2 C. The other nice thing about the 1655 is that you have a reference output that is perfect for setting output range and even changing the output to + -. In a message dated 12/30/2011 9:48:38 P.M. Eastern Standard Time, davidwh...@gmail.com writes: Did you test the LTC1655 INL? The data sheet says plus or minus 20 counts maximum. I suspect Linear Technology designed those low DNL high INL parts for just this sort of application where only monotonic behavior really matters. Their equivalent current output DAC costs about twice as much not including a precision transimpedance amplifier but has an INL specification of plus or minus 1 count. Every couple years I consider the design of a digitally adjusted oscillator and do a search for likely parts. I wonder if it would be more cost effective to use an instrumentation ADC to correct a less expensive DAC design like one based on a PWM. On Fri, 30 Dec 2011 17:48:24 -0500 (EST), ewkeh...@aol.com wrote: Over the last two years along with two list members that may want to pipe in, I have spend a large amount of time on D/A's and we went as far as developing a test board using the LTC 2440 and testing numerous D/A's taking in to consideration performance, solderability, cost, availability and the winner is LTC 1655 by a long shot, is even available in a DIP with 16 bits more than you need for any Rb and if you want 20 bits, dithering is an option. My testing consistently shows with OCXO's aging that will in most cases allow operation of an OCXO for 3 years with out intervention. To top it off the LTC1655 cost less than $ 10. Testing the old AD 1861 was an eye opener but considering what its purpose was and its time the best choice. Bert In a message dated 12/30/2011 4:24:37 P.M. Eastern Standard Time, timen...@n4iqt.com writes: The DAC and it's voltage reference looks to be the weak link in the digital control and the simple goal. The CPU I mentioned before on closer look doesn't have a good DAC. The 20 bit TI DAC1220 looks better but not sure you can find it in the same package as the CPU. The cheap Rb standards with digital control would not need a DAC and maybe this points to a simpler GPSDO that doesn't control the XO with analog but corrects it with a DDS but again finding them both in one chip is the problem. I have seen OCXO and DAC in the same package and even the DDS and OCXO combined but they didn't fit the simple goal. Not even sure how good they were. I know they are hard to find. Stanley ___ time-nuts mailing 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] Speaking of shipments from China
That would be a mighty small skirt On Fri, Dec 30, 2011 at 11:21 PM, Said Jackson saidj...@aol.com wrote: Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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] Speaking of shipments from China
When I asked one seller to mark the correct value and description, he explained to me that they have to mark it as a low value item and call it something allowed by their postal system! Usually they mark it as a gift!! When I got a Rubedium osc.. I was hauled up by customs and the officer saw atomic on the unit and thought radio active.. an explanation of Rubedium lamp inside is similar to a sodium vapour lamp etc, he was pacified to let it go with a small duty. Happy new year! Raj - vu2zap That would be a mighty small skirt On Fri, Dec 30, 2011 at 11:21 PM, Said Jackson saidj...@aol.com wrote: Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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] Speaking of shipments from China
Just to be clear ... you (the USPS) are subsidizing the Chinese Postal System. Who do you think pays for the delivery of your package once it hits our shores. 73, Dick, W1KSZ -Original Message- From: Said Jackson saidj...@aol.com Sent: Dec 30, 2011 9:21 PM To: li...@lazygranch.com li...@lazygranch.com, Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Speaking of shipments from China Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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] Speaking of shipments from China
But if you send something to China, who do you think pays for the delivery there? - Original Message - From: Richard W. Solomon w1...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, 31 December, 2011 4:30:38 PM Subject: Re: [time-nuts] Speaking of shipments from China Just to be clear ... you (the USPS) are subsidizing the Chinese Postal System. Who do you think pays for the delivery of your package once it hits our shores. 73, Dick, W1KSZ -Original Message- From: Said Jackson saidj...@aol.com Sent: Dec 30, 2011 9:21 PM To: li...@lazygranch.com li...@lazygranch.com, Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Speaking of shipments from China Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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] Speaking of shipments from China
But Chinese postmen (postwomen) get paid a lot less than USPS employees. -John But if you send something to China, who do you think pays for the delivery there? - Original Message - From: Richard W. Solomon w1...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, 31 December, 2011 4:30:38 PM Subject: Re: [time-nuts] Speaking of shipments from China Just to be clear ... you (the USPS) are subsidizing the Chinese Postal System. Who do you think pays for the delivery of your package once it hits our shores. 73, Dick, W1KSZ -Original Message- From: Said Jackson saidj...@aol.com Sent: Dec 30, 2011 9:21 PM To: li...@lazygranch.com li...@lazygranch.com, Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Speaking of shipments from China Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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] Speaking of shipments from China
I'm finding this thread a great source of amusement. It's no wonder the Chinese are eating our lunch. First, intellectual property is an oxymoron to them. Second, cheating is a way of life; root hog or die. Third, push the system until it burps, then back off just a little. Actually, I enjoy low cost, free shipping, and direct purchase. There's no chain of distributors, reps, quotes, wholesalers, etc to deal with. OTH, it is caveat emptor, and lots of the stuff is crap. It's kinda like dope. Remember? know your dealer. Happy New Year to all of ya! PS I call all goods going to Canada used Amateur radio equipment. Don Richard W. Solomon Just to be clear ... you (the USPS) are subsidizing the Chinese Postal System. Who do you think pays for the delivery of your package once it hits our shores. 73, Dick, W1KSZ -Original Message- From: Said Jackson saidj...@aol.com Sent: Dec 30, 2011 9:21 PM To: li...@lazygranch.com li...@lazygranch.com, Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Speaking of shipments from China Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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.
Re: [time-nuts] Thunderbolt? (re simple gpsdo.)
Chris Here is a GPSDO I built that better fits Your definition of Simple. I used this as my freq standard before getting a TBolt. 1) Feed the PPS output of an oncore GPS timing engine which has 1 Hz or better yet 100 Hz output to the clk of a D FlipFlop (74HC74) 2) Feed the FF's D from a 10 MHz osc which has been divided down to 100KHz or less using 74HC390. The FF output shows if the Phase of the Osc is greater or less than the GPS signal and the FF will toggle back and forth when the phases are near equal due to the typical 40 ns jitter on the GPS pulse signal. 3) Add a RC filter to the FF output using a big cap, so the voltage out of the RC filter is 0 to 5 volts depending on the duty cycle of the FF. (A small R in series with the cap will help stabilize it if a real Big cap is used). 4) Feed the filtered analog FF output voltage (No buffering necessary) to the EFC of an 10 MHz osc that has its EFC input desensitized with a couple of Rs and has been set to be real near 10 MHz at the nominal analog FF's 2.5 volts output using the Osc's mechanical tuning and/or add a fine freq adj pot. A couple basic ICs and a few Rs and Cs and you're done. This makes a basic PI controller that will cause the 10MHz osc to track the GPS PPS. The less you make the Osc's EFC tuning range the better this works, and Once it is tracking you can fine tune the freq adj pot every now and then to keep the Filtered FF voltage at near 2.5 volts if the Osc tends to drift outside of the control range. Not very high tech and there are Lots of possible ways to add more parts to improve it further, depending on what your goals are and how much you want to learn about GPSDO and PID control loops. If the definition of simple is less parts and more programming you can replace all the active parts with a simple PIC and get better performance by controlling the Osc's EFC using a software PID and PWM with an external RC filter as the Dac. ws Chris Albertson albertson.chris at gmail.com Sat Dec 31 06:01:38 UTC 2011 On Fri, Dec 30, 2011 at 10:16 AM, Hal Murray hmurray at megapathdsl.net wrote: Software. As soon as you say Software the device is no longer simple.Even a microprocessor is a very complex device and so is its development system. The software inside the uP is not simple either if you count the number of possible paths through the code (2 raided to the power of the number of branches.) I have nothing against software, that is what I do for a living, every day. But you can't count a uP with software indise as simple. And the point of this exercise is to find the simplest thing that can still work. 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] Speaking of shipments from China
I'm also enjoying all the feedback since my original post. I look at this way; these Rubidiums are probably in the region of $1000 new. We're getting them for a song. OK, you take the risk of the odd dud, but that's the way of fleabay. I will let you all know how UK Customs performs on my shipment if when it arrives! Happy New Year to all Time Nutters out there. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham Sent: 31 December 2011 17:12 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Speaking of shipments from China I'm finding this thread a great source of amusement. It's no wonder the Chinese are eating our lunch. First, intellectual property is an oxymoron to them. Second, cheating is a way of life; root hog or die. Third, push the system until it burps, then back off just a little. Actually, I enjoy low cost, free shipping, and direct purchase. There's no chain of distributors, reps, quotes, wholesalers, etc to deal with. OTH, it is caveat emptor, and lots of the stuff is crap. It's kinda like dope. Remember? know your dealer. Happy New Year to all of ya! PS I call all goods going to Canada used Amateur radio equipment. Don Richard W. Solomon Just to be clear ... you (the USPS) are subsidizing the Chinese Postal System. Who do you think pays for the delivery of your package once it hits our shores. 73, Dick, W1KSZ -Original Message- From: Said Jackson saidj...@aol.com Sent: Dec 30, 2011 9:21 PM To: li...@lazygranch.com li...@lazygranch.com, Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Speaking of shipments from China Mine was declared a woman's silk shirt for some reason.. Not sure why. Sent From iPhone On Dec 30, 2011, at 17:41, li...@lazygranch.com wrote: I got a feebay shipment from China today. Duty? No problem, it was declared a gift. ;-) ___ time-nuts mailing 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] Used Rb Operating Lifetime
I agree that they are an amazing value but what kind of operating lifetime do the Rb tubes have? SRS has this to say: Historically, the lifetime of rubidium frequency standards has been dominated by rubidium depletion in the discharge lamp. To avoid excess flicker noise, manufacturers would load less than 100 µg of rubidium into spherical discharge lamps. The PRS10 uses a lamp with a side arm loaded with 1 mg of rubidium. This design eliminates rubidium depletion as a failure mechanism, and provides better temperature control without excess flicker noise. http://www.thinksrs.com/products/PRS10.htm On Sat, 31 Dec 2011 18:56:32 -, Rob Kimberley robkimber...@btinternet.com wrote: I'm also enjoying all the feedback since my original post. I look at this way; these Rubidiums are probably in the region of $1000 new. We're getting them for a song. OK, you take the risk of the odd dud, but that's the way of fleabay. I will let you all know how UK Customs performs on my shipment if when it arrives! Happy New Year to all Time Nutters out there. Rob Kimberley ___ time-nuts mailing 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] Used Rb Operating Lifetime
They seem to run a while especially if you reheat the bulb as discussed several times in these threads. So for $38 I am taking the gamble. Have 5 older units and have recovered one of them by reheating the lamp. So far the others are good and I do not run those 24 X 7. Instead should the main go I will grab the next one and use it. Regards Paul. WB8TSL/1 On Sat, Dec 31, 2011 at 2:30 PM, David davidwh...@gmail.com wrote: I agree that they are an amazing value but what kind of operating lifetime do the Rb tubes have? SRS has this to say: Historically, the lifetime of rubidium frequency standards has been dominated by rubidium depletion in the discharge lamp. To avoid excess flicker noise, manufacturers would load less than 100 µg of rubidium into spherical discharge lamps. The PRS10 uses a lamp with a side arm loaded with 1 mg of rubidium. This design eliminates rubidium depletion as a failure mechanism, and provides better temperature control without excess flicker noise. http://www.thinksrs.com/products/PRS10.htm On Sat, 31 Dec 2011 18:56:32 -, Rob Kimberley robkimber...@btinternet.com wrote: I'm also enjoying all the feedback since my original post. I look at this way; these Rubidiums are probably in the region of $1000 new. We're getting them for a song. OK, you take the risk of the odd dud, but that's the way of fleabay. I will let you all know how UK Customs performs on my shipment if when it arrives! Happy New Year to all Time Nutters out there. Rob Kimberley ___ time-nuts mailing 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? (re simple gpsdo.)
I think this is the simplest design that can still work, just one flip flop, divider and a capacitor. What level of performance did you get?I think it depends on how big the integrating capacitor is and how stable the VCXO is. I guess if you switched to using the t-bolt the performance was not as good as a t-bolt. On Sat, Dec 31, 2011 at 10:23 AM, WarrenS warrensjmail-...@yahoo.comwrote: Chris Here is a GPSDO I built that better fits Your definition of Simple. I used this as my freq standard before getting a TBolt. 1) Feed the PPS output of an oncore GPS timing engine which has 1 Hz or better yet 100 Hz output to the clk of a D FlipFlop (74HC74) 2) Feed the FF's D from a 10 MHz osc which has been divided down to 100KHz or less using 74HC390. The FF output shows if the Phase of the Osc is greater or less than the GPS signal and the FF will toggle back and forth when the phases are near equal due to the typical 40 ns jitter on the GPS pulse signal. 3) Add a RC filter to the FF output using a big cap, so the voltage out of the RC filter is 0 to 5 volts depending on the duty cycle of the FF. (A small R in series with the cap will help stabilize it if a real Big cap is used). 4) Feed the filtered analog FF output voltage (No buffering necessary) to the EFC of an 10 MHz osc that has its EFC input desensitized with a couple of Rs and has been set to be real near 10 MHz at the nominal analog FF's 2.5 volts output using the Osc's mechanical tuning and/or add a fine freq adj pot... 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] Thunderbolt? (re simple gpsdo.)
Chris posted: What level of performance did you get? Correct it depends on what parts you use and how nutty you want to get. So much also depends on how you define performance, and where you want to compromise. Compared to WWV and WWVB it was much better, Compared to a correctly set up TBolt much worse. In a NUT-Shell, It is good of enough for most any REAL non-Nut application. Ball park numbers: Freq error of 1e-8 is simple, 1e-9 is easy, 1e-11 gets hard without some good parts and lots of care to details. Besides the GPS engine and the Osc, The time period the freq is averaged over is an important factor, because of the jitter. If you do not loose sync, like all GPSDO, over a long enough time period of many days or weeks, it is good enough to check and calibrate ANY Osc, because it can be set up so that there is NO long term accumulative drift, just short term freq jitter. just one flip-flop, divider and a capacitor. AND some resistors I'm looking for a controller that is much more like the bimetallic spring thermostat. For a Bang bang type two state controller like your bimetallic example, you don't even need the cap which is added to filter out freq jitter. Take out the filter cap, scale and adjust things right and what it does is if the freq is less than the GPS, when the FF toggles it will raise the freq above the GPS and then when the phase matches, it will toggle back and lower the freq below the GPS. This will continue forever keeping the AVERAGE Osc Freq dead nuts on bouncing back and forth between a couple frequencies in what then becomes a PWM like function of the OSC bouncing between two frequencies, one higher and one lower than 10.000 MHz. The freq step size and jitter is a function of the resistor divider used and the EFC sensitivity. The PWM cycle rate depends on freq step size, the speed of the PPS signal, the osc divider used and GPS PPS phase noise. Lots of other uses for this type of D FF as a basic ns hi-low Phase detector for low freq signals. Remove the EFC feedback, Reduce the 100 to 1 divider to two or so and you can use this to measure and/or manually set a Rb Osc to be on frequency if you have an accurate 1PPS signal. ws [time-nuts] Thunderbolt? (re simple gpsdo.) Chris Albertson albertson.chris at gmail.com Sat Dec 31 20:34:14 UTC 2011 I think this is the simplest design that can still work, just one flip flop, divider and a capacitor. What level of performance did you get?I think it depends on how big the integrating capacitor is and how stable the VCXO is. I guess if you switched to using the t-bolt the performance was not as good as a t-bolt. On Sat, Dec 31, 2011 at 10:23 AM, WarrenS warrensjmail-one at yahoo.comwrote: Chris Here is a GPSDO I built that better fits Your definition of Simple. I used this as my freq standard before getting a TBolt. 1) Feed the PPS output of an oncore GPS timing engine which has 1 Hz or better yet 100 Hz output to the clk of a D FlipFlop (74HC74) 2) Feed the FF's D from a 10 MHz osc which has been divided down to 100KHz or less using 74HC390. The FF output shows if the Phase of the Osc is greater or less than the GPS signal and the FF will toggle back and forth when the phases are near equal due to the typical 40 ns jitter on the GPS pulse signal. 3) Add a RC filter to the FF output using a big cap, so the voltage out of the RC filter is 0 to 5 volts depending on the duty cycle of the FF. (A small R in series with the cap will help stabilize it if a real Big cap is used). 4) Feed the filtered analog FF output voltage (No buffering necessary) to the EFC of an 10 MHz osc that has its EFC input desensitized with a couple of Rs and has been set to be real near 10 MHz at the nominal analog FF's 2.5 volts output using the Osc's mechanical tuning and/or add a fine freq adj pot... Chris Albertson Redondo Beach, California snip Home heating thermostats can be simple of complex. Some use LCD displays and a computer. Other have a simple bimetallic spring inside. But for now I'm looking for a controller that is much more like the bimetallic spring thermostat. 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] HBG keeps transmitting...
The HBG has survived the 00:00 CET and the 00:00 UTC. I was fulfilling the task of recording the final transmission instant but now I don't know how to proceed. Unfortunately I have no audio time lapse recorder at hand and I have no more ideas about the time when they will shutdown.. Maybe I have to write an email to ask? ___ time-nuts mailing 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] HBG keeps transmitting...
Probably when the hung over teckies get back in to work in a state they can find the off switch :-)) Alan G3NYK - Original Message - From: Azelio Boriani azelio.bori...@screen.it To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, January 01, 2012 12:16 AM Subject: [time-nuts] HBG keeps transmitting... The HBG has survived the 00:00 CET and the 00:00 UTC. I was fulfilling the task of recording the final transmission instant but now I don't know how to proceed. Unfortunately I have no audio time lapse recorder at hand and I have no more ideas about the time when they will shutdown.. Maybe I have to write an email to ask? ___ time-nuts mailing 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] HBG keeps transmitting...
Must live under a rock. Did not know HBG was going away. On Sat, Dec 31, 2011 at 7:23 PM, Alan Melia alan.me...@btinternet.comwrote: Probably when the hung over teckies get back in to work in a state they can find the off switch :-)) Alan G3NYK - Original Message - From: Azelio Boriani azelio.bori...@screen.it To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, January 01, 2012 12:16 AM Subject: [time-nuts] HBG keeps transmitting... The HBG has survived the 00:00 CET and the 00:00 UTC. I was fulfilling the task of recording the final transmission instant but now I don't know how to proceed. Unfortunately I have no audio time lapse recorder at hand and I have no more ideas about the time when they will shutdown.. Maybe I have to write an email to ask? ___ time-nuts mailing 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] eBay Ublox
UBLOX TIM-CJ module TIM-ST GPS engine Jupiter footprint anyone have any experience with this for timing application? N0UU ___ time-nuts mailing 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] HBG keeps transmitting...
I find it peaceful under rocks. Happy New Year all! Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Saturday, December 31, 2011 6:31 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HBG keeps transmitting... Must live under a rock. Did not know HBG was going away. On Sat, Dec 31, 2011 at 7:23 PM, Alan Melia alan.me...@btinternet.comwrote: Probably when the hung over teckies get back in to work in a state they can find the off switch :-)) Alan G3NYK - Original Message - From: Azelio Boriani azelio.bori...@screen.it To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, January 01, 2012 12:16 AM Subject: [time-nuts] HBG keeps transmitting... The HBG has survived the 00:00 CET and the 00:00 UTC. I was fulfilling the task of recording the final transmission instant but now I don't know how to proceed. Unfortunately I have no audio time lapse recorder at hand and I have no more ideas about the time when they will shutdown.. Maybe I have to write an email to ask? ___ time-nuts mailing 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] Thunderbolt? (re simple gpsdo.)
OTH, if it's an OCXO, then the thermal time constants can be made large thermos bottles, etc.? Don WarrenS Chris posted: What level of performance did you get? Correct it depends on what parts you use and how nutty you want to get. So much also depends on how you define performance, and where you want to compromise. Compared to WWV and WWVB it was much better, Compared to a correctly set up TBolt much worse. In a NUT-Shell, It is good of enough for most any REAL non-Nut application. Ball park numbers: Freq error of 1e-8 is simple, 1e-9 is easy, 1e-11 gets hard without some good parts and lots of care to details. Besides the GPS engine and the Osc, The time period the freq is averaged over is an important factor, because of the jitter. If you do not loose sync, like all GPSDO, over a long enough time period of many days or weeks, it is good enough to check and calibrate ANY Osc, because it can be set up so that there is NO long term accumulative drift, just short term freq jitter. just one flip-flop, divider and a capacitor. AND some resistors I'm looking for a controller that is much more like the bimetallic spring thermostat. For a Bang bang type two state controller like your bimetallic example, you don't even need the cap which is added to filter out freq jitter. Take out the filter cap, scale and adjust things right and what it does is if the freq is less than the GPS, when the FF toggles it will raise the freq above the GPS and then when the phase matches, it will toggle back and lower the freq below the GPS. This will continue forever keeping the AVERAGE Osc Freq dead nuts on bouncing back and forth between a couple frequencies in what then becomes a PWM like function of the OSC bouncing between two frequencies, one higher and one lower than 10.000 MHz. The freq step size and jitter is a function of the resistor divider used and the EFC sensitivity. The PWM cycle rate depends on freq step size, the speed of the PPS signal, the osc divider used and GPS PPS phase noise. Lots of other uses for this type of D FF as a basic ns hi-low Phase detector for low freq signals. Remove the EFC feedback, Reduce the 100 to 1 divider to two or so and you can use this to measure and/or manually set a Rb Osc to be on frequency if you have an accurate 1PPS signal. ws [time-nuts] Thunderbolt? (re simple gpsdo.) Chris Albertson albertson.chris at gmail.com Sat Dec 31 20:34:14 UTC 2011 I think this is the simplest design that can still work, just one flip flop, divider and a capacitor. What level of performance did you get?I think it depends on how big the integrating capacitor is and how stable the VCXO is. I guess if you switched to using the t-bolt the performance was not as good as a t-bolt. On Sat, Dec 31, 2011 at 10:23 AM, WarrenS warrensjmail-one at yahoo.comwrote: Chris Here is a GPSDO I built that better fits Your definition of Simple. I used this as my freq standard before getting a TBolt. 1) Feed the PPS output of an oncore GPS timing engine which has 1 Hz or better yet 100 Hz output to the clk of a D FlipFlop (74HC74) 2) Feed the FF's D from a 10 MHz osc which has been divided down to 100KHz or less using 74HC390. The FF output shows if the Phase of the Osc is greater or less than the GPS signal and the FF will toggle back and forth when the phases are near equal due to the typical 40 ns jitter on the GPS pulse signal. 3) Add a RC filter to the FF output using a big cap, so the voltage out of the RC filter is 0 to 5 volts depending on the duty cycle of the FF. (A small R in series with the cap will help stabilize it if a real Big cap is used). 4) Feed the filtered analog FF output voltage (No buffering necessary) to the EFC of an 10 MHz osc that has its EFC input desensitized with a couple of Rs and has been set to be real near 10 MHz at the nominal analog FF's 2.5 volts output using the Osc's mechanical tuning and/or add a fine freq adj pot... Chris Albertson Redondo Beach, California snip Home heating thermostats can be simple of complex. Some use LCD displays and a computer. Other have a simple bimetallic spring inside. But for now I'm looking for a controller that is much more like the bimetallic spring thermostat. 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com
Re: [time-nuts] Thunderbolt? (re simple gpsdo.)
As soon as you say Software the device is no longer simple.Even a microprocessor is a very complex device and so is its development system. The software inside the uP is not simple either if you count the number of possible paths through the code (2 raided to the power of the number of branches.) Yes and no... Software doesn't have to be big, bloated, ugly, and complicated. (But I agree that it often is.) This looks like fun to me, but I like writing that sort of code. Note that it doesn't need an OS or even any libraries. The context for simple wasn't well specified. Does simple refer to design or construction? How good does the GPSDO have to be? (After all, this is time nuts.) What sort of adev at what sort of time scale? I think the main problem in this area is building a low pass filter with a long time constant. The time constant of the filter has to be: long relative to the noise from the phase detector short relative to aging of the oscillator short relative to environmental changes (so the osc can track temperature and voltage those changes may be in the PLL system rather than the osc) If we are starting with PPS (rather than 10KHz), the filter time constant needs to be 10s or 100s of seconds. How do I build an analog filter with a time constant that long? What's the input impedance of a VCXO or Rb unit? I assume we will need an op-amp to buffer the filter. The ugly problem in this area is that time constant to filter out phase detector noise overlaps the time constant needed to let environmental changes through. That doesn't matter if the filter is analog or digital. If the osc is stable (Rb) filter time constants of 1000s of seconds might make sense. That might help take care of some of the hanging bridges. For those who aren't familiar with this trick, it's easy to make a low pass filter in software: X = X*(1-k) + k*new or X = X -k*X + k*new where k is less than one. Smaller k makes a slower filter. If you pick k as a (negative) power of 2, the multiplies can be done with a shift so there is nothing complicated with making filters with a very long time constant. (You may have to use multi-precision arithmetic, but that's not a big deal.) -- These are my opinions, not necessarily my employer's. 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.
Re: [time-nuts] Thunderbolt? (re simple gpsdo.)
On Sat, 31 Dec 2011 17:56:46 -0800, Hal Murray hmur...@megapathdsl.net wrote: This looks like fun to me, but I like writing that sort of code. Note that it doesn't need an OS or even any libraries. Both designs look fun to me but for different reasons. The analog design requires attention to leakage and noise while the digital design requires high resolution, good DNL, and attention to cycle accurate counting. My ongoing notebook doodles are tending toward using a simple PIC as a cycle accurate frequency comparator and high resolution low frequency oscillator to drive a high resolution frequency to voltage converter. The part I have not figured out is measuring phase below one cycle without frequency multiplication. There must be a better way than doing a time to voltage conversion. I figure I could get better than 17 bits of INL and 20 bits of DNL for the OCXO control signal. The context for simple wasn't well specified. Does simple refer to design or construction? I would say that simple means diagnosis can be performed with a multimeter and oscilloscope and all parts are user replaceable without any programming. I think the main problem in this area is building a low pass filter with a long time constant. The time constant of the filter has to be: long relative to the noise from the phase detector short relative to aging of the oscillator short relative to environmental changes (so the osc can track temperature and voltage those changes may be in the PLL system rather than the osc) If we are starting with PPS (rather than 10KHz), the filter time constant needs to be 10s or 100s of seconds. How do I build an analog filter with a time constant that long? Use op-amp integrators and pay careful attention to leakage. Because of the long time constant involved, tuning it will be arduous. If noise is a problem, it might be worth using a discrete FET differential amplifier input stage. The phase detector should probably be disconnected when GPS lock is lost to prevent integrator windup. A fast time constant mode would make for a faster lock. I think a dual phase/frequency detector could be used to indicate when a lock has been achieved. What's the input impedance of a VCXO or Rb unit? I assume we will need an op-amp to buffer the filter. I would probably drive it directly from an op-amp integrator output. The ugly problem in this area is that time constant to filter out phase detector noise overlaps the time constant needed to let environmental changes through. That doesn't matter if the filter is analog or digital. In a state variable filter you can adjust the filter cutoff by adjusting the integrator gain. I did something like this in a low noise chopper stabilized amplifier that I designed where I adjusted the integrator time constant via the gain for lowest output noise and amazingly enough, it ended up matching the bipolar amplifier noise corner frequency very closely. When set too high, the broadband noise from the chopper stabilized amplifier rose and when set too low, the 1/f noise from the bipolar amplifier rose. The whole thing worked well enough that I could measure the resistance of a piece of wire from its Johnson noise. If the osc is stable (Rb) filter time constants of 1000s of seconds might make sense. That might help take care of some of the hanging bridges. For those who aren't familiar with this trick, it's easy to make a low pass filter in software: X = X*(1-k) + k*new or X = X -k*X + k*new where k is less than one. Smaller k makes a slower filter. If you pick k as a (negative) power of 2, the multiplies can be done with a shift so there is nothing complicated with making filters with a very long time constant. (You may have to use multi-precision arithmetic, but that's not a big deal.) Would you measure the differential phase and then update the filter and output every second? ___ time-nuts mailing 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? (re simple gpsdo.)
On Sat, Dec 31, 2011 at 5:56 PM, Hal Murray hmur...@megapathdsl.net wrote: As soon as you say Software the device is no longer simple.Even a microprocessor is a very complex device and so is its development system. The software inside the uP is not simple either if you count the number of possible paths through the code (2 raided to the power of the number of branches.) Yes and no... Software doesn't have to be big, bloated, ugly, and complicated. (But I agree that it often is.) If you have eight if statements you have 2^8 = 256 possible paths through the code. For a hobby application I goes you'd not bother to write up and run 256 test cases. This looks like fun to me, but I like writing that sort of code. Note that it doesn't need an OS or even any libraries. The context for simple wasn't well specified. Does simple refer to design or construction? I think simple means you can explain how it works in a few sentences. And if software is used you have to explain every calculation and decision point. With software design and construction is the same thing if you only build one unit. How good does the GPSDO have to be? (After all, this is time nuts.) What sort of adev at what sort of time scale? I think the main problem in this area is building a low pass filter with a long time constant. The time constant of the filter has to be: long relative to the noise from the phase detector short relative to aging of the oscillator short relative to environmental changes (so the osc can track temperature and voltage those changes may be in the PLL system rather than the osc) If we are starting with PPS (rather than 10KHz), the filter time constant needs to be 10s or 100s of seconds. How do I build an analog filter with a time constant that long? Time constant is just R*C. If you have a 1000uF cap and a 1K resistor you have 1 second. In theory you could build 100s just by using a 100K resistor but I think real world components are not perfect enough. What's the input impedance of a VCXO or Rb unit? I assume we will need an op-amp to buffer the filter. I suspect you are right. The ugly problem in this area is that time constant to filter out phase detector noise overlaps the time constant needed to let environmental changes through. That doesn't matter if the filter is analog or digital. If the osc is stable (Rb) filter time constants of 1000s of seconds might make sense. That might help take care of some of the hanging bridges. The new $38 Rb units can only be adjust by RS-232 commands. So you need a digital controller. No choice there. The best oscillator for an analog controller would have to be a high quality ovenized crystal. About the time constants. If you are doing this in software then you can track performance inside the controller and adjust. Seems you shouod be able to tell the controller the tau you need and it should be able to optimize. Once you have a uP then more features are easy to do, like maybe using multiple GPS receivers or maybe fault detection and switching to holdover mode For those who aren't familiar with this trick, it's easy to make a low pass filter in software: X = X*(1-k) + k*new Designing filters seems like an art. What is the frequency response of the above for different values of k? I tend to like FIR filters because I think I understand them better. I think yours is an IIR. 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.
