Re: [time-nuts] Fury - Rubidium
Hi Scott, a cool thing to try is to put the unit into manual holdover by issuing the command sync:holdover:init The unit will act as if the GPS antenna has been removed, but GPSCon will continue to show the 1PPS phase drift against GPS. Thus you can see how stable your LPRO is over time when the unit is in holdover. You can restart normal locking with the command sync:holdover:rec:init On a good DOCXO, we would see less than 2000ns drift over a day when the unit has been stable for a week or so. I believe the limits of the time interval display are about +/- 2000ns. bye, Said In a message dated 7/27/2010 08:42:01 Pacific Daylight Time, sm...@intt.net writes: I test it by changing the antenna delay. It should recover within a reasonable time. Bumping the coarsedac is typically too much change and takes longer to recover. I run it with a 20ns offset to my z3801a, and they always stay within 20ns of other. I've had the Fury running for about 5400 hours since the last reboot, running v1.21 firmware. It stays within +-10ns, usually it's between +-5ns. Over 24hrs, gpscon reports TI average 0.15 or so and stddev around 2.5ns. ___ time-nuts mailing 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] Fury - Rubidium - PIS
Hi Scott, yes, Rb's tend to have many orders of magnitude smaller control ranges than OCXO's, so it takes longer to phase lock. What's even worse is hysterisis, eg. we have seen units that jump back and forth between two control voltage values. This tends to happen in TCXO's and Rbs from what I can tell, not so much in good OCXO's. It seems that these units do not change their output frequency until the EFC voltage change reaches some threshold, then the frequency jumps in a large value. OCXO's seem to react instantly to even the slightest LSB changes on our 24 bit DAC. Many Rb's and TCXO's seem to have this spring-like effect, and that causes some "chasing" of the phase as the oscillators "ignores" the EFC voltage changes until they reach a certain level, at which time they over-compensate and the effect reverses. I am wondering if adding some dithering noise would help prevent this effect, where the noise bandwidth is below the Rb's control bandwidth so as not to add ADEV instability... Does anyone know how popular Rb's adjust their frequency? Is it through linear methods such as Varactor diodes? Or do they use an ADC to sample the EFC voltage, thus creating quantization errors that could be the cause of the hysterisis we sometimes see? Brian, on a locked DOCXO unit (after a day or so typically) we would like to see below 5ns SD on the GPS TI. Good DOCXO units regularly achieve <2.5ns. No reason a good Rb should not be able to achieve that as well. The DOCXO unit running at the University of Colima for example regularly achieves ~1.8ns SD. For some reason the TI indicator has not been visible for some months now though, but the plot still speaks for itself. Notice also the small control voltage range of less than 50 microvolts typically: _http://resco.ucol.mx/Fury/gpsstat.htm_ (http://resco.ucol.mx/Fury/gpsstat.htm) bye, Said In a message dated 7/27/2010 20:11:00 Pacific Daylight Time, sm...@intt.net writes: After _MANY_ hours of watching and playing with different settings, I came to the conclusion that you just need to be patient when using Fury+Rb, don't expect it to converge like an OCXO, but it will over a few hours and give you a good result as long as you have stable power and shield it from air streams. ___ time-nuts mailing 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] Fury - Rubidium
Hi Scott, this one has about 3K at 60C and 10K at room temp. We used it before with success. The only problem is having sufficient current go through it to be above the cut-off threshold of the current sensor. You may have to put something in parallel to this thermistor, or use a couple in parallel to get a couple of mA of current flow. When it works right, you should see the current increase (as indicated by meas?) as temperature rises. You can add the meas? output to be tracked by GPSCon for graphing. Panasonic ERT-J1VG103JA Available on Digikey. bye, Said In a message dated 7/27/2010 19:55:40 Pacific Daylight Time, sm...@intt.net writes: Any particular thermistor you would recommend? Scott ___ time-nuts mailing 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] Fury - Rubidium - Status
I also noticed on the Fury I had the original firmware in the unit from when I was bought (Oct 14,2007). I have not had a chance to play with the unit unit recently. I reflashed the unit with 1.22 firmware. I noticed in the flash software I could not select the DEVICE LCP2136, it was greyed out. But If you told it to read the device ID, it set it for you. I set the jumper on the Fury, flashed it, powered it down, moved the jumper back and powered it back up. Did I tell you I had removed the backup battery as it was dead ? So when I brought it back up, the GPS receiver did not have an almanac. So I had to wait about 20 minutes before the receiver would come up. I then entered my LAT/LONG/Height, and the oscillator ops parameters again. Then unit was finally up about 20 minutes later. I set the DAC Gain to 1000, the EFC scale to 1.0 and the EFC damping to 25. I checked on the unit an hour later and it was reporting it was locked. GPSCon reported an EFC of 1.425642 AD 4.93m sd=74.91m. The GPS TI was av=9.23n sd=41.8n. After reading Said's email, I have set the unit to 10,000 for the DAC Gain, 1.4 for the EFCS and 60 for EFCD. I'll report results tomorrow, got to get to bed. Thanks for all the help. Brian - KD4FM ___ time-nuts mailing 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] Fury - Rubidium - PIS
You really can't expect to be able to tweek a loop without giving it several time constants (at least) to settle out between changes. -John == > I found that on the FRS-C and the X72 the frequency output was not at > all linear with respect to EFC, which made things worse with large > dacgains. After _MANY_ hours of watching and playing with different > settings, I came to the conclusion that you just need to be patient when > using Fury+Rb, don't expect it to converge like an OCXO, but it will > over a few hours and give you a good result as long as you have stable > power and shield it from air streams. High dacgain and efcs give you > the false hope that it will converge fast, but as the unit settles the > loop will fail, and it will start fighting with itself. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Fury - Rubidium - PIS
I found that on the FRS-C and the X72 the frequency output was not at all linear with respect to EFC, which made things worse with large dacgains. After _MANY_ hours of watching and playing with different settings, I came to the conclusion that you just need to be patient when using Fury+Rb, don't expect it to converge like an OCXO, but it will over a few hours and give you a good result as long as you have stable power and shield it from air streams. High dacgain and efcs give you the false hope that it will converge fast, but as the unit settles the loop will fail, and it will start fighting with itself. The SYNC:IMME can be useful when trying different loop settings. I found some of my notes for various things I ran with the Fury. LPRO-101 currently running COARSE DAC: 55 DAC GAIN: 1000 EFC SCALE: 1.30 OCXO SLOPE: POSITIVE temp co: 0.00 aging co: -0.00558 phase co: 35 lpro orig lpro cd 92 dac gain 1000 efc scale 1.30 efc damping 2 efc slope pos phase co 30 lpro 2 coarse dac 95 dac gain 1300 efcs 1.30 efcdamping 5 ocxo slope pos agin comp 0.05333 phaseco 35 datum ocxo #1 (From RFG-XO) coarse dac 64 dac gain 80 efcs 4 efcdamping 10 ocxo slope pos agin comp 0.27086 phaseco 35 datum ocxo #2 coarse dac 64 dac gain 100 efcs 2.8 efcdamping 10 ocxo slope pos agin comp 0.14901 phaseco 35 datum ocxo #2 from RFG-XO In an RFG chassis cd 69 dg 30.00 efcs 12.00 efcd 5 ocxo slope pos aging comp -0.06559 phaseco 40 tempco was a major issue with the datum ocxo keeping it in the RFG-XO chassis helped Efratom FRS-A DAC GAIN: 5000.00 EFC SCALE: 0.50 EFC DAMPING: 25 OCXO SLOPE: POSITIVE PHASE CORRECTION: 0.50 TTL output, pad to below +13dBm, FRS-A needs to settle, open bench air current problems. FRS-A #2 dac gain: 4000 efcs: 1.2 efcdamping: 25 phaseco: 15 hard time recovering, from coarsedac bumps X72 dac gain: 2000 efcs 1.2 efcdamping 25 phaseco: 15 jumps, tempco issues. Scott On 07/27/2010 09:16 PM, saidj...@aol.com wrote: Hi John, Brian, actually we set D to 0, and use P and I gains. Yes, the DACGAIN is an overall gain of the loop output - to normalize for different oscillator voltage/frequency sensitivities. I forgot that the DACGAIN is limited to 10,000, so instead of setting it to 20,000 one can set it to 10,000 and multiply the P and I parts both by 2x, that gives pretty much the same effect as setting DACGAIN to 20,000. Please note that aging and tempco compensation may then take a couple of days to fully settle again. I have not tried such high gains since we don't have any oscillators here with such small F/V range, please advise what you find out. bye, Said In a message dated 7/27/2010 19:04:36 Pacific Daylight Time, j...@quik.com writes: That part I understand (your drawing), its a basic phase lock loop. What I am having trouble with is the Fury's commands relationship. OK. Sorry for the BW. Basically you tune a loop by starting with the P, I, and D set to zero. You slowly crank up the P until it starts to become unstable. (Put in a small step perturbation and look at the response for ringing) Then crank up the D until it stabilizes, then crank up the P again. When you have got a stable fairly well performing loop, you introduce some I. You may have to tweek P and D to keep stability. It looks like your system has an overall gain (DACG) and a P and D controller gain. This is not uncommon to avoid switching a bunch of caps. ___ time-nuts mailing 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] Fury - Rubidium
Any particular thermistor you would recommend? Scott On 07/27/2010 09:07 PM, saidj...@aol.com wrote: Hi Scott, yes the pads are there, you can use the through-hole pad right next to C67 and a standard ground pad for the Thermistor. There will be 10.5V across the thermistor. Connect the thermistor to your Rb case. You should be able to connect two 10K Thermistors in parallel to get a good reading without excessive self-heating of the thermistors, while generating enough current through them that can be measured by the ADC. You can check the thermistor current using the meas? command. If the thermistor is not drawing enough current for the ADC, then simply place a 2.2K resistor in parallel to it. The software needs to be enabled to support measuring and applying a tempco correction, by default I think the boards were shipped with only aging compensation enabled. Us the following command to enable tempco correction: serv:tas 2,288,600,50,0.05 Check the settings with: serv:tas? The first number is the mode (0 is all off, 1 is aging only, 2 is aging and tempco correction). The second number is the memory usage, 288 points in this case. The third number is the sensing frequency in seconds, so 10 minute intervals in this example. 288 points * 10 minutes is 48 hours of memory. The fourth number is the maximum phase offset allowed for a sense point, in this case +/-50ns. The last item is the required frequency error estimate for a sense point, in this case +/-0.05ppb. bye, Said In a message dated 7/27/2010 17:07:31 Pacific Daylight Time, sm...@intt.net writes: Said, Did the OEM units (from way back) ship with an open pad for the thermistor? I thought that wouldn't work unless it was drawing oven current from the Fury. It would be neat to add some tempco into the mix instead of just trying to shield it from HVAC cycling. The particular LPRO-101 that I'm using now, doesn't seem to be as sensitive as others to temp. I was using a different LPRO originally and when I plotted the Fury board temp sensor with GPSCON you could see the impact of the cycling, now with this one you would be hard pressed to pick it out. The X72 was very sensitive to temp changes, EFC tracked the temp quite well. Scott ___ time-nuts mailing 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] Fury - Rubidium - PIS
Hi John, Brian, actually we set D to 0, and use P and I gains. Yes, the DACGAIN is an overall gain of the loop output - to normalize for different oscillator voltage/frequency sensitivities. I forgot that the DACGAIN is limited to 10,000, so instead of setting it to 20,000 one can set it to 10,000 and multiply the P and I parts both by 2x, that gives pretty much the same effect as setting DACGAIN to 20,000. Please note that aging and tempco compensation may then take a couple of days to fully settle again. I have not tried such high gains since we don't have any oscillators here with such small F/V range, please advise what you find out. bye, Said In a message dated 7/27/2010 19:04:36 Pacific Daylight Time, j...@quik.com writes: > That part I understand (your drawing), its a basic phase lock loop. > What I am having trouble with is the Fury's commands relationship. OK. Sorry for the BW. Basically you tune a loop by starting with the P, I, and D set to zero. You slowly crank up the P until it starts to become unstable. (Put in a small step perturbation and look at the response for ringing) Then crank up the D until it stabilizes, then crank up the P again. When you have got a stable fairly well performing loop, you introduce some I. You may have to tweek P and D to keep stability. It looks like your system has an overall gain (DACG) and a P and D controller gain. This is not uncommon to avoid switching a bunch of caps. ___ time-nuts mailing 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] Fury - Rubidium
Hi Scott, yes the pads are there, you can use the through-hole pad right next to C67 and a standard ground pad for the Thermistor. There will be 10.5V across the thermistor. Connect the thermistor to your Rb case. You should be able to connect two 10K Thermistors in parallel to get a good reading without excessive self-heating of the thermistors, while generating enough current through them that can be measured by the ADC. You can check the thermistor current using the meas? command. If the thermistor is not drawing enough current for the ADC, then simply place a 2.2K resistor in parallel to it. The software needs to be enabled to support measuring and applying a tempco correction, by default I think the boards were shipped with only aging compensation enabled. Us the following command to enable tempco correction: serv:tas 2,288,600,50,0.05 Check the settings with: serv:tas? The first number is the mode (0 is all off, 1 is aging only, 2 is aging and tempco correction). The second number is the memory usage, 288 points in this case. The third number is the sensing frequency in seconds, so 10 minute intervals in this example. 288 points * 10 minutes is 48 hours of memory. The fourth number is the maximum phase offset allowed for a sense point, in this case +/-50ns. The last item is the required frequency error estimate for a sense point, in this case +/-0.05ppb. bye, Said In a message dated 7/27/2010 17:07:31 Pacific Daylight Time, sm...@intt.net writes: Said, Did the OEM units (from way back) ship with an open pad for the thermistor? I thought that wouldn't work unless it was drawing oven current from the Fury. It would be neat to add some tempco into the mix instead of just trying to shield it from HVAC cycling. The particular LPRO-101 that I'm using now, doesn't seem to be as sensitive as others to temp. I was using a different LPRO originally and when I plotted the Fury board temp sensor with GPSCON you could see the impact of the cycling, now with this one you would be hard pressed to pick it out. The X72 was very sensitive to temp changes, EFC tracked the temp quite well. Scott ___ time-nuts mailing 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] Fury - Rubidium - PIS
> That part I understand (your drawing), its a basic phase lock loop. > What I am having trouble with is the Fury's commands relationship. OK. Sorry for the BW. Basically you tune a loop by starting with the P, I, and D set to zero. You slowly crank up the P until it starts to become unstable. (Put in a small step perturbation and look at the response for ringing) Then crank up the D until it stabilizes, then crank up the P again. When you have got a stable fairly well performing loop, you introduce some I. You may have to tweek P and D to keep stability. It looks like your system has an overall gain (DACG) and a P and D controller gain. This is not uncommon to avoid switching a bunch of caps. FWIW, -John == > > The Fury controller has the following SERVO commands to set up the loop: > > SERVo:DACG which is the DAC gain, a control voltage range ? > range is 0.1 to 10,000 -- the DAC is 0 to +5V > > SERVo:EFCS which is the EFC Scale, proportional gain of the PID loop > range is 0.0 to 500.0 -- 0.7 example for a good double oven and 6.0 for > a simple single oven > > SERVo:EFCD which is IIR filter time constant > range is 0.0 to 4000.0 -- example between 10 and 50 > > Thanks - Brian KD4FM > > > On 7/27/2010 8:36 PM, J. Forster wrote: >>> I read the article on PID on Wikipedia last night. I do not fully >>> understand it, but I see/learning some of the relationship. >> >> Here's a very quick primer: >> >> Consider a very simple control position servo loop: >> >> >> Pos. Input --- + (SUM)--- PID --- AMP> --- MOTOR = Output Pos >> |- || >> | POS Sensor >> | | >> --- >> >> >> If you put an upwards step into the Pos Input the output of the SUM goes >> up. This is applied to the AMP via the PID network and the MOTOR stasrts >> up, turning the output shaft. As the Output shaft turns, the position >> sensor output rises. That subtracts from the commanded position in the >> SUM, reducing the AMP input. >> >> Thats how the P = Proportional signal drives the loop to null. >> >> However, in order for the motor to turn some non-zero voltage needs to >> be >> applied. As the SUM output approaches zero the motor drive ceases and >> the >> loop never reaches null. So the I = Integral term is added. If the loop >> stops just shy of null, the SUM output will not be zero. The I >> Integrator >> takes the near-null voltage and integrates it (Vsum dT) which will >> eventually rise sufficiently to drive the motor to null. >> >> However, the motor does not stop instantly when the SUM reaches zero >> because of inertia, so it overshoots. So the D = Derivative term >> (dVsum/dT)is added in to cut the motor drive as the loop approaches >> null. >> >> Note, in general the I term is destabilizing and the D term is >> stabilizing, as long as you are considering frequencies below where the >> othy components have significant phase shift. >> >> FWIW, >> >> -John >> >> = >> >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Fury - Rubidium
Hi John, on the Fury, the proportional part you describe is roughly the same as EFC Scale. The integral part is PHASECO. Fury can happily run with correct frequency output with PHASECO set to 0, but the phase offset would be large, and slowly changing over time. The EFCS (proportional part) makes sure the frequency is correct, and the PHASECO (integral part) makes sure the phase error is "integrated out" to 0.0ns. hope that helps, bye, Said In a message dated 7/27/2010 18:37:20 Pacific Daylight Time, j...@quik.com writes: > I read the article on PID on Wikipedia last night. I do not fully > understand it, but I see/learning some of the relationship. Here's a very quick primer: Consider a very simple control position servo loop: Pos. Input --- + (SUM)--- PID --- AMP > --- MOTOR = Output Pos |- || | POS Sensor | | --- If you put an upwards step into the Pos Input the output of the SUM goes up. This is applied to the AMP via the PID network and the MOTOR stasrts up, turning the output shaft. As the Output shaft turns, the position sensor output rises. That subtracts from the commanded position in the SUM, reducing the AMP input. Thats how the P = Proportional signal drives the loop to null. However, in order for the motor to turn some non-zero voltage needs to be applied. As the SUM output approaches zero the motor drive ceases and the loop never reaches null. So the I = Integral term is added. If the loop stops just shy of null, the SUM output will not be zero. The I Integrator takes the near-null voltage and integrates it (Vsum dT) which will eventually rise sufficiently to drive the motor to null. ___ time-nuts mailing 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] Fury - Rubidium - PIS
That part I understand (your drawing), its a basic phase lock loop. What I am having trouble with is the Fury's commands relationship. The Fury controller has the following SERVO commands to set up the loop: SERVo:DACG which is the DAC gain, a control voltage range ? range is 0.1 to 10,000 -- the DAC is 0 to +5V SERVo:EFCS which is the EFC Scale, proportional gain of the PID loop range is 0.0 to 500.0 -- 0.7 example for a good double oven and 6.0 for a simple single oven SERVo:EFCD which is IIR filter time constant range is 0.0 to 4000.0 -- example between 10 and 50 Thanks - Brian KD4FM On 7/27/2010 8:36 PM, J. Forster wrote: I read the article on PID on Wikipedia last night. I do not fully understand it, but I see/learning some of the relationship. Here's a very quick primer: Consider a very simple control position servo loop: Pos. Input --- + (SUM)--- PID --- AMP> --- MOTOR = Output Pos |- || | POS Sensor | | --- If you put an upwards step into the Pos Input the output of the SUM goes up. This is applied to the AMP via the PID network and the MOTOR stasrts up, turning the output shaft. As the Output shaft turns, the position sensor output rises. That subtracts from the commanded position in the SUM, reducing the AMP input. Thats how the P = Proportional signal drives the loop to null. However, in order for the motor to turn some non-zero voltage needs to be applied. As the SUM output approaches zero the motor drive ceases and the loop never reaches null. So the I = Integral term is added. If the loop stops just shy of null, the SUM output will not be zero. The I Integrator takes the near-null voltage and integrates it (Vsum dT) which will eventually rise sufficiently to drive the motor to null. However, the motor does not stop instantly when the SUM reaches zero because of inertia, so it overshoots. So the D = Derivative term (dVsum/dT)is added in to cut the motor drive as the loop approaches null. Note, in general the I term is destabilizing and the D term is stabilizing, as long as you are considering frequencies below where the othy components have significant phase shift. FWIW, -John = ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Fury - Rubidium
Hi Brian, based on your measurements, it seems that your unit has a swing of about 0.00566 Hertz per Volt EFC, which is very little. This compares to about 8Hz per volt for the standard DOCXO's we use. That's a 1413 to 1 difference in EFC sensitivity between the Rb and the standard OCXO. We use a dacgain of 15 for the standard OCXO, so try 15 * 1400 = 21,000 for the Dacgain (that's a lot of dacgain!) We use 0.7 for EFCS, and 15 for PHASECO, and 40 to 80 for EFC Damping. Unfortunately we do not have the Rb's here in house that you are using to try this out. Let me know if that works, bye, Said In a message dated 7/27/2010 17:46:42 Pacific Daylight Time, kilodelta4foxm...@gmail.com writes: I did another test and the rubidium dial setting was 000 for a control voltage of 0.068V and the average frequency was 9 999 999.9933 hertz. The dial setting was changed to 721 for a control voltage of 4.V and the average frequency was 10 000 000.0216 hertz The measurements were taken with a HP5370B time interval counter referenced to a HP5065A rubidium oscillator. The data was recorded using a ProLogix GPIB adapter. The data was recorded in 10 minute intervals with the data coming in at one measurement a second. When the frequency was changed, I allowed 20 minutes between the recordings. Based on the above measurements, Said, can you recommend some starting point for the DAC Gain, EFC Scale, and the EFC Damping ? ___ time-nuts mailing 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] Fury - Rubidium
> I read the article on PID on Wikipedia last night. I do not fully > understand it, but I see/learning some of the relationship. Here's a very quick primer: Consider a very simple control position servo loop: Pos. Input --- + (SUM)--- PID --- AMP > --- MOTOR = Output Pos |- || | POS Sensor | | --- If you put an upwards step into the Pos Input the output of the SUM goes up. This is applied to the AMP via the PID network and the MOTOR stasrts up, turning the output shaft. As the Output shaft turns, the position sensor output rises. That subtracts from the commanded position in the SUM, reducing the AMP input. Thats how the P = Proportional signal drives the loop to null. However, in order for the motor to turn some non-zero voltage needs to be applied. As the SUM output approaches zero the motor drive ceases and the loop never reaches null. So the I = Integral term is added. If the loop stops just shy of null, the SUM output will not be zero. The I Integrator takes the near-null voltage and integrates it (Vsum dT) which will eventually rise sufficiently to drive the motor to null. However, the motor does not stop instantly when the SUM reaches zero because of inertia, so it overshoots. So the D = Derivative term (dVsum/dT)is added in to cut the motor drive as the loop approaches null. Note, in general the I term is destabilizing and the D term is stabilizing, as long as you are considering frequencies below where the othy components have significant phase shift. FWIW, -John = ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Fury - Rubidium
I read the article on PID on Wikipedia last night. I do not fully understand it, but I see/learning some of the relationship. I did a test on the FRS-C rubidium. The average frequency was 10 000 000.0025 hertz at the rubidium 10 turn dial dial setting of 255, and the control voltage out of the pot was 1.7900 volts. I recorded the frequency for a while and then changed frequency to see how long it took to get there. I changed the dial setting to 516 (3.5800V) and it took 8 seconds for the rubidium to change frequency and settle on a average frequency of 10, 000 000.0131 hertz. I did another test and the rubidium dial setting was 000 for a control voltage of 0.068V and the average frequency was 9 999 999.9933 hertz. The dial setting was changed to 721 for a control voltage of 4.V and the average frequency was 10 000 000.0216 hertz The measurements were taken with a HP5370B time interval counter referenced to a HP5065A rubidium oscillator. The data was recorded using a ProLogix GPIB adapter. The data was recorded in 10 minute intervals with the data coming in at one measurement a second. When the frequency was changed, I allowed 20 minutes between the recordings. Based on the above measurements, Said, can you recommend some starting point for the DAC Gain, EFC Scale, and the EFC Damping ? Also from previous measurements, I know this particular rubidium was at 9x10E-11 at 0.1 sec, 1.8x10E-11 at 1 second, 5x10E-12 at 10 seconds, 1.5x10E-12 at 100 seconds, 7x10E-13 for 1000 seconds, and 2.5x10E-13 for 1 seconds - running on a Shera GPS controller - which the PIC was modified for this rubidium (it was changed from a 30 second time interval measurement to 120 seconds, and Shera changed the sensitivity of the PIC to 1X10-9/volt). Thanks to Don and Scott for the ops info. Thanks Brian KD4FM On 7/27/2010 2:57 PM, saidj...@aol.com wrote: Hi guys, it may help to increase DAC gain to get faster recovery times from "bumps" etc. On an OCXO, the frequency recovery from an upset should happen within a couple of minutes, definitely less than 15 minutes to achieve frequency lock. The phase recovery (to 0ns offset) may take a couple of hours to do. If it takes a very long time to recover, then I think increasing the DAC gain, or alternatively the EFCS and PHASECO together may help. Wikipedia has some good instructions on how to optimize PID type controller gains to get the fastest response with minimal noise... Also, please make sure to disable temperature compensation when using the external source, unless a thermistor is connected to the board, sensing the Rb temperature. Otherwise the temperature compensation may add noise due to it scaling the gain to huge values due to the missing thermistor. bye, Said In a message dated 7/27/2010 09:58:41 Pacific Daylight Time, true-...@swbell.net writes: My experience is very similar to Scott's. I ran many hours with both an LPRO-101 and FE-5680A. The disciplining behavior and Fury settings were the same for either Rb. My biggest disappointment was the recovery time due to various common or intentional bumps or especially, after power loss. I also had to let the "system" settle in for a week before acceptable tracking smoothed out. Any long term slope to the EFC trace (gpscon) caused excessive hunting and this didn't settle down until the Rb was VERY stable. My gpscon TI and stddev was virtually the same as Scott's if I had EFCS set to 1.0 to 1.5 but recovery was unacceptable (maybe 24-hours) so I usually ran at 2.0 or 3.0 with slight degrading of stddev to around 3.2. This EFCS setting allowed a much better settling time around 3-hours. DACG= 1000 EFCS = 2 to 3 EFCD = 50 (25 allows little better settling time) PHASECO = 15 (I favor 10 Mhz over PPS) Regards... Don ___ time-nuts mailing 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] Fury - Rubidium
Said, Did the OEM units (from way back) ship with an open pad for the thermistor? I thought that wouldn't work unless it was drawing oven current from the Fury. It would be neat to add some tempco into the mix instead of just trying to shield it from HVAC cycling. The particular LPRO-101 that I'm using now, doesn't seem to be as sensitive as others to temp. I was using a different LPRO originally and when I plotted the Fury board temp sensor with GPSCON you could see the impact of the cycling, now with this one you would be hard pressed to pick it out. The X72 was very sensitive to temp changes, EFC tracked the temp quite well. Scott On 07/27/2010 02:57 PM, saidj...@aol.com wrote: Hi guys, it may help to increase DAC gain to get faster recovery times from "bumps" etc. On an OCXO, the frequency recovery from an upset should happen within a couple of minutes, definitely less than 15 minutes to achieve frequency lock. The phase recovery (to 0ns offset) may take a couple of hours to do. If it takes a very long time to recover, then I think increasing the DAC gain, or alternatively the EFCS and PHASECO together may help. Wikipedia has some good instructions on how to optimize PID type controller gains to get the fastest response with minimal noise... Also, please make sure to disable temperature compensation when using the external source, unless a thermistor is connected to the board, sensing the Rb temperature. Otherwise the temperature compensation may add noise due to it scaling the gain to huge values due to the missing thermistor. bye, Said In a message dated 7/27/2010 09:58:41 Pacific Daylight Time, true-...@swbell.net writes: My experience is very similar to Scott's. I ran many hours with both an LPRO-101 and FE-5680A. The disciplining behavior and Fury settings were the same for either Rb. My biggest disappointment was the recovery time due to various common or intentional bumps or especially, after power loss. I also had to let the "system" settle in for a week before acceptable tracking smoothed out. Any long term slope to the EFC trace (gpscon) caused excessive hunting and this didn't settle down until the Rb was VERY stable. My gpscon TI and stddev was virtually the same as Scott's if I had EFCS set to 1.0 to 1.5 but recovery was unacceptable (maybe 24-hours) so I usually ran at 2.0 or 3.0 with slight degrading of stddev to around 3.2. This EFCS setting allowed a much better settling time around 3-hours. DACG= 1000 EFCS = 2 to 3 EFCD = 50 (25 allows little better settling time) PHASECO = 15 (I favor 10 Mhz over PPS) Regards... Don ___ time-nuts mailing 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] HP 5061A on auction 290458191620
Could be they can't check but the meter still should work That would say a lot. Well to much for me to gamble away. On Tue, Jul 27, 2010 at 10:53 AM, Pete Lancashire wrote: > >> with a cal lab for defence department contracts > > Or maybe they don't have the ability to check for output :-) > > > > On Tue, Jul 27, 2010 at 7:04 AM, swingbyte > wrote: > > On 27/07/2010 11:16 PM, paul swed wrote: > >> > >> it is funny. But maybe those options did turn it into a network > analyzer. > >> Powers up untested $1300 AU. Well thats a great gamble for those with > >> spare > >> cash. > >> > >> On Tue, Jul 27, 2010 at 9:03 AM, Javier > >> Herrerowrote: > >> > >>> I've enjoyed the description. Particularly the "These atoms are > processed > >>> is such a way that they become an atomic frequency standard" :) Also > the > >>> history section... and the characteristics (Frequency Accuracy: +/-5 > ppm > >>> <--- a little bad for a cesium, right? ;) or Frequency Range: 300KHz – > >>> 1.5GHz<--- not so bad... ) So I don't know if option 3 and 4 refers to > >>> the > >>> 5061A or to the network analyzer specifications from which the seller > >>> seems > >>> to have messed at writing the description. > >>> > >>> Regards, > >>> > >>> Javier > >>> > >>> El 27/07/2010 12:37, Mark Stephens escribió: > >>> > >>> 5061A opt 3 and opt 4 > > Ebay# 290458191620 > > Not mine but wish it was. > > > Mark > VK2HMC > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > >>> -- > >>> > > >>> Javier HerreroEMAIL: > jherr...@hvsistemas.com > >>> HV Sistemas S.L. PHONE: +34 949 336 > 806 > >>> Los Charcones, 17 FAX: +34 949 336 > 792 > >>> 19170 El Casar - Guadalajara - Spain WEB: > http://www.hvsistemas.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. > >> > > The seller runs a real store as well as a cal lab for defence department > > contracts - so should be able to test. That they don't test it suggests > > that they may be are covering for selling an inoperative item or they > can't > > afford the time to test it. In Australia these are rare and would only > come > > from the dod which has recently shut down and outsourced its cal labs. or > > telecom. Either way its old and overpriced. I 'd like to know how the > > other ones they have sold ended up? > > They may have been on continuously for 30 years. > > > > > > > > > > > > > > > > ___ > > time-nuts mailing 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] Fury - Rubidium
Hi guys, it may help to increase DAC gain to get faster recovery times from "bumps" etc. On an OCXO, the frequency recovery from an upset should happen within a couple of minutes, definitely less than 15 minutes to achieve frequency lock. The phase recovery (to 0ns offset) may take a couple of hours to do. If it takes a very long time to recover, then I think increasing the DAC gain, or alternatively the EFCS and PHASECO together may help. Wikipedia has some good instructions on how to optimize PID type controller gains to get the fastest response with minimal noise... Also, please make sure to disable temperature compensation when using the external source, unless a thermistor is connected to the board, sensing the Rb temperature. Otherwise the temperature compensation may add noise due to it scaling the gain to huge values due to the missing thermistor. bye, Said In a message dated 7/27/2010 09:58:41 Pacific Daylight Time, true-...@swbell.net writes: My experience is very similar to Scott's. I ran many hours with both an LPRO-101 and FE-5680A. The disciplining behavior and Fury settings were the same for either Rb. My biggest disappointment was the recovery time due to various common or intentional bumps or especially, after power loss. I also had to let the "system" settle in for a week before acceptable tracking smoothed out. Any long term slope to the EFC trace (gpscon) caused excessive hunting and this didn't settle down until the Rb was VERY stable. My gpscon TI and stddev was virtually the same as Scott's if I had EFCS set to 1.0 to 1.5 but recovery was unacceptable (maybe 24-hours) so I usually ran at 2.0 or 3.0 with slight degrading of stddev to around 3.2. This EFCS setting allowed a much better settling time around 3-hours. DACG= 1000 EFCS = 2 to 3 EFCD = 50 (25 allows little better settling time) PHASECO = 15 (I favor 10 Mhz over PPS) Regards... Don ___ time-nuts mailing 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] RACAL-DANA 1992 Option 04E problem
Thank you all for replying to the post. Channel C works up to 1,750 MHz on both units. Channel A works up to 220 MHz on both units. My applications are for GPS L1 at 1575.42 MHz , L2 at 1227.6 MHz, and L5 at 1176.45 MHz and their corresponding LOs. I did consider that the OCXO may be defective, but I didn't trouble shoot it. I just ran the unit with the lid off and it worked for 24 hours. So, I just drilled the holes. The TCXO unit did not over-heat. The two units track each other within 10 Hz (LSD) at 1,575.42 MHz. I also have one EIP 545A WITH Option 05 (OCXO). I use the EIP 545A 10 MHz OCXO output as the external reference for the HP 8656B. I use a frequency doubler to obtain 1575.42 MHz. Thanks for your help, Bill Hanna ___ time-nuts mailing 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] Fury - Rubidium
My experience is very similar to Scott's. I ran many hours with both an LPRO-101 and FE-5680A. The disciplining behavior and Fury settings were the same for either Rb. My biggest disappointment was the recovery time due to various common or intentional bumps or especially, after power loss. I also had to let the "system" settle in for a week before acceptable tracking smoothed out. Any long term slope to the EFC trace (gpscon) caused excessive hunting and this didn't settle down until the Rb was VERY stable. My gpscon TI and stddev was virtually the same as Scott's if I had EFCS set to 1.0 to 1.5 but recovery was unacceptable (maybe 24-hours) so I usually ran at 2.0 or 3.0 with slight degrading of stddev to around 3.2. This EFCS setting allowed a much better settling time around 3-hours. DACG= 1000 EFCS = 2 to 3 EFCD = 50 (25 allows little better settling time) PHASECO = 15 (I favor 10 Mhz over PPS) Regards... Don From: Scott Mace To: time-nuts@febo.com Sent: Tue, July 27, 2010 10:41:16 AM Subject: Re: [time-nuts] Fury - Rubidium I have done this with several LPRO-101, X72, and a FRS-C. The FRS-C that I used was out of a Lucent RFG-RB box. It had a hot TTL output that was causing issues with the Fury, The level was the problem, not the ttl. The EFC was hypersensitive, and it took a long time for the unit to settle down before the Fury would handle it. Same thing with the LPRO, and X72, you have to wait for it settle for a week or so before it starts to work well if it's been off for a long time. The X72 was by far the worst, and it would jump from time to time, which would make the fury unhappy. I didn't have a chassis that would fit the FRS-C and the fury, so I just went back to the LPRO. The lpro-101 has been the best so far. I put everything in a 1U chassis and placed it in the bottom of my rack away from the AC vent. This is what I use with the LPRO-101. dac gain: 1000 efc scale: 1.30 efc damping: 35 ocxo slope: positive phaseco: 35 I test it by changing the antenna delay. It should recover within a reasonable time. Bumping the coarsedac is typically too much change and takes longer to recover. I run it with a 20ns offset to my z3801a, and they always stay within 20ns of other. I've had the Fury running for about 5400 hours since the last reboot, running v1.21 firmware. It stays within +-10ns, usually it's between +-5ns. Over 24hrs, gpscon reports TI average 0.15 or so and stddev around 2.5ns. Scott On 7/27/2010 9:07 AM, Brian Kirby wrote: > Has anybody on the list interfaced a Fury GPS controller to a rubidium ? > > If you have, please advise the rubidium are using and your SERV:DACG , > SERV:EFCS , and SERV:EFCD settings. > > I am working with a FRS-C at the moment and I have not found the right > combination to get a stable lock. > > Thanks - Brian KD4FM > > ___ > time-nuts mailing 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] RACAL-DANA 1992 Option 04E problems
Are you sure that the OCXO is failing? I bought two 1992s. One was basically dead. A custom IC (U39) was running at 90C with no heatsink. In the working unit U39 was ~60C. One of this chip's functions is to process the oscillator before it's sent to the 10MHz STD. OUTPUT jack on the back. U39 is the socketed 40 pin dip located on the right side, in front of the OCXO. Maybe your unit has a flaky U39. Ed bill...@aol.com wrote: I own one RACAL-DANA 1992 (Standard- TCXO). I purchased one with the Option 04E on eBAY. The 04E chassis is sealed and the internal OCXO overheats due to lack of cooling air. This causes the counter to stop taking measurements. I had to add ventilation holes on the top and right side of the chassis lid to obtain reliable operation. Both counters work up to 1,750 MHz. Bill Hanna = ___ time-nuts mailing 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] Sale TRACOR527E
I have both the 527A and 527E manuals already scanned if you want them. My 527E is missing the info one he one card that is different between the models. Luciano and I are trying to work that out now. Best, -John === > > > Luciano, > > When you get it scanned I will be happy to host > it on the www.to-way.com Web site. > > Hadley > K7MLR > h...@to-way.com > > > At 08:01 AM 7/27/2010, you wrote: >> Hi, >>I confirm the manual is for the E model.I will >>scan it.I hope will be ready next week. >>Luciano >> >> >>Luciano P. S. Paramithiotti >>IZ5JHJ >> >>-Original Message- >>From: time-nuts-boun...@febo.com >>[mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster >>Sent: martedì 27 luglio 2010 16.32 >>To: Discussion of precise time and frequency measurement >>Subject: Re: [time-nuts] Sale TRACOR527E >> >>Hi, >> >>Is the manual for the 527E or for the 527A? AFAIK, the difference is only >>1 card but there are no drawings of that card available. >> >>It would be a real public service to scan or copy it before selling your >> unit. >> >>If you have a real 527E manual copy, please contact me off-list. >> >>Thanks, >> >>-John >> >>= >> >> >> > >> > Hi all, >> > For sale Tracor 527E frequency difference meter. Accept 1,5,10 Mhz >> > perfectly working come with manual copy.One front handle is missing. >> > Price 350,00 Euros Shipping from Italy not included. Paypal account or >> > Poste Pay if in Italy. >> > If interested replay writing your personal email address.I will >> > contact you directly. >> > Thanks all you, >> > Luciano >> > IZ5JHJ >> > ___ >> > time-nuts mailing 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. > > > > A fine is a tax for doing wrong. A tax is a fine for doing well. > > Peter Cooper, of Fermi Lab, says, "Every experimentalist knows > that the apparatus, or at least your understanding of it, is > always at fault until demonstrated otherwise." He also says, > "Nature is really unmoved by what I, or anyone else, believes." > > > > > > > > > > > ___ > time-nuts mailing 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] Sale TRACOR527E
Luciano, When you get it scanned I will be happy to host it on the www.to-way.com Web site. Hadley K7MLR h...@to-way.com At 08:01 AM 7/27/2010, you wrote: Hi, I confirm the manual is for the E model.I will scan it.I hope will be ready next week. Luciano Luciano P. S. Paramithiotti IZ5JHJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: martedì 27 luglio 2010 16.32 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Sale TRACOR527E Hi, Is the manual for the 527E or for the 527A? AFAIK, the difference is only 1 card but there are no drawings of that card available. It would be a real public service to scan or copy it before selling your unit. If you have a real 527E manual copy, please contact me off-list. Thanks, -John = > > Hi all, > For sale Tracor 527E frequency difference meter. Accept 1,5,10 Mhz > perfectly working come with manual copy.One front handle is missing. > Price 350,00 Euros Shipping from Italy not included. Paypal account or > Poste Pay if in Italy. > If interested replay writing your personal email address.I will > contact you directly. > Thanks all you, > Luciano > IZ5JHJ > ___ > time-nuts mailing 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. A fine is a tax for doing wrong. A tax is a fine for doing well. Peter Cooper, of Fermi Lab, says, "Every experimentalist knows that the apparatus, or at least your understanding of it, is always at fault until demonstrated otherwise." He also says, "Nature is really unmoved by what I, or anyone else, believes." ___ time-nuts mailing 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] Fury - Rubidium
I have done this with several LPRO-101, X72, and a FRS-C. The FRS-C that I used was out of a Lucent RFG-RB box. It had a hot TTL output that was causing issues with the Fury, The level was the problem, not the ttl. The EFC was hypersensitive, and it took a long time for the unit to settle down before the Fury would handle it. Same thing with the LPRO, and X72, you have to wait for it settle for a week or so before it starts to work well if it's been off for a long time. The X72 was by far the worst, and it would jump from time to time, which would make the fury unhappy. I didn't have a chassis that would fit the FRS-C and the fury, so I just went back to the LPRO. The lpro-101 has been the best so far. I put everything in a 1U chassis and placed it in the bottom of my rack away from the AC vent. This is what I use with the LPRO-101. dac gain: 1000 efc scale: 1.30 efc damping: 35 ocxo slope: positive phaseco: 35 I test it by changing the antenna delay. It should recover within a reasonable time. Bumping the coarsedac is typically too much change and takes longer to recover. I run it with a 20ns offset to my z3801a, and they always stay within 20ns of other. I've had the Fury running for about 5400 hours since the last reboot, running v1.21 firmware. It stays within +-10ns, usually it's between +-5ns. Over 24hrs, gpscon reports TI average 0.15 or so and stddev around 2.5ns. Scott On 7/27/2010 9:07 AM, Brian Kirby wrote: Has anybody on the list interfaced a Fury GPS controller to a rubidium ? If you have, please advise the rubidium are using and your SERV:DACG , SERV:EFCS , and SERV:EFCD settings. I am working with a FRS-C at the moment and I have not found the right combination to get a stable lock. Thanks - Brian KD4FM ___ time-nuts mailing 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] RACAL-DANA 1992 Option 04E problems
bill...@aol.com wrote: I own one RACAL-DANA 1992 (Standard- TCXO). I purchased one with the Option 04E on eBAY. The 04E chassis is sealed and the internal OCXO overheats due to lack of cooling air. This causes the counter to stop taking measurements. I had to add ventilation holes on the top and right side of the chassis lid to obtain reliable operation. Both counters work up to 1,750 MHz. Bill Hanna Bill I have had several of these through my hands over the years and the outside of the crystal oven does get hot but not exceptionally so. Certainly it should /not/ require any extra ventilation. I would suspect that you have a faulty oven heater controller in there and that the heater is running at full current all the time. What frequency does the standard put out? The frequency and the current drawn by the oven should both settle down after about 15 minutes from cold. Also if you really meant 1,750 MHz on both inputs that's way better than it should be, pretty amazing really :^) Dan ___ time-nuts mailing 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] RACAL-DANA 1992 Option 04E problems
Strange, there is no mention of the need to add ventilation when you upgrade to ocxo in the service manual. Steve On 28/07/2010, bill...@aol.com wrote: > > I own one RACAL-DANA 1992 (Standard- TCXO). I purchased one with > the Option 04E on eBAY. > > The 04E chassis is sealed and the internal OCXO overheats due to > lack of cooling air. This causes the counter to stop taking measurements. > I had to add ventilation holes on the top and right side of the chassis lid > to obtain reliable operation. > > Both counters work up to 1,750 MHz. > > Bill Hanna > > > > > = > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing 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] RACAL-DANA 1992 Option 04E problems
I own one RACAL-DANA 1992 (Standard- TCXO). I purchased one with the Option 04E on eBAY. The 04E chassis is sealed and the internal OCXO overheats due to lack of cooling air. This causes the counter to stop taking measurements. I had to add ventilation holes on the top and right side of the chassis lid to obtain reliable operation. Both counters work up to 1,750 MHz. Bill Hanna = ___ time-nuts mailing 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] Sale TRACOR527E
Hi, I confirm the manual is for the E model.I will scan it.I hope will be ready next week. Luciano Luciano P. S. Paramithiotti IZ5JHJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: martedì 27 luglio 2010 16.32 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Sale TRACOR527E Hi, Is the manual for the 527E or for the 527A? AFAIK, the difference is only 1 card but there are no drawings of that card available. It would be a real public service to scan or copy it before selling your unit. If you have a real 527E manual copy, please contact me off-list. Thanks, -John = > > Hi all, > For sale Tracor 527E frequency difference meter. Accept 1,5,10 Mhz > perfectly working come with manual copy.One front handle is missing. > Price 350,00 Euros Shipping from Italy not included. Paypal account or > Poste Pay if in Italy. > If interested replay writing your personal email address.I will > contact you directly. > Thanks all you, > Luciano > IZ5JHJ > ___ > time-nuts mailing 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] Heathkid - New time-nut needs help [Update]
You might want to look at this link for useful info on the 5680A, http://www.qsl.net/zl1bpu/PROJ/Ruby.htm, and right down the bottom of this link, http://www.redrok.com/misc1.htm. 73 de Steve On 28/07/2010, Steve Rooke wrote: > Kia Ora Brice, > > On 27/07/2010, Heathkid wrote: > >> Yes, the FEI 5680A's I got are programmable from 1Hz to 20MHz (SMA output >> / >> currently set to 10MHz) plus has the RS232 for programming and one of >> those >> pins (besides the Rb lock pin that goes low and I've got a LED on it) has >> the 1pps. Besides the "C" field potentiometer it also has a 0 to 5V fine >> tune voltage. The slowest of the three takes only about 4 seconds to >> achieve Rb lock. Here are the exact units I got (and "flyingbest" is a >> great and honest seller): >> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180435915714 > > Not the cheapest I have seen but at least you have a full kit and they > are the programmable ones. What's the PSU like, how good is the > regulation on it as this will have a factor on how clean the output > is. Monitor the voltage at startup right through to it running stable > and see if it changes. There seems to be no requirement for +5V for > programming the device in the listing you quote but others have > indicated that this needs to be connected to pin 4 of the DB-9. That > being said, the info I have, > http://www.mail-archive.com/time-nuts@febo.com/msg01569.html, does not > show a C field adjustment on pin 8. The SMA connector looks like it > has been retrofitted IMHO so it would be interesting to pop the hood > and look for any mods done by the seller. > >> The Thunderbolt I bought from fluke.l as he seems to be the "TBolt seller >> of >> choice" around here. I also got the LCD display option (looks like fun >> to >> see what it's doing when not connected to a PC). > > Yes, I'm yet to get one of those LCD displays although there is quite > a discussion thread on these in the archives and you can see the > background to this. Before you put the LCD display on for long term > use, I suggest you run it with Lady Heather to see how it it is > tracking sats and stabilising. The tuning of the PLL constants is the > subject of quite a few threads in the archives so you can learn a lot > from that. Once your happy that it's running fine, connect the LCD > display but I'd run it for a few weeks before you get to that stage as > the ocxo will have been sitting on the shelf cold and you want to see > how that is shaping up (this will take months before the xo really > beds in). You should also keep an eye on it continuing to track sats > as some people have found that their TB's have completely lost the > plot at times. When you first start it up it won't know what the heck > is going on as the location it was last running will be internally > stored and it will be looking for sats in the sky and not seeing them. > You should make sure it does a survey straight away so that sanity is > restored and/or you can enter your exact location of the antenna if > you know that. > > I don't know your location but you should make sure that your antenna > is located in a good position where it has a good sight to the south > and look out for multipath reception, trees, buildings, etc. but your > a ham anyway and must be in a good position to fix it up as your doing > QRP. > >> Okay, so today... I bought a "real" frequency counter. After a LOT of >> looking and reading... I chose a HP 5335A. It has option 10 (Oven >> Oscillator) and 030 (C Channel 1.3 GHz ) plus the HPIB plus math and >> statistics functions standard and includes operating and service manuals >> on >> CD. It'll also be calibrated just prior to shipping to me (current Date >> Due >> 03/19/11) but it will be re-calibrated just for me so at least I know >> it'll >> work and if there is a problem, I can return it. :) > > Well, that's a nice purchase and I'm sure it will serve you well. > >> So, now I have the following (when the rest shows up): >> >> (3) FEI 5680A Programmable Rubidium Frequency Standards w/ 1pps >> (1) Thunderbolt "Complete Kit" w/ LCD display - from fluke.l >> (1) HP 5335A Universal Counter w/ Options 10 (Oven Oscillator) & 030 (C >> Channel 1.3 GHz) > > Well, that's a start, or should I say, the slippery slope :) You'll > have a good setup with this and have a decent frequency standard for > your lab equipment. You can program those 5680A's to output directly > on some of the HF bands and have a Rb controlled QRP rig :) > >> Hopefully, Stanley got my payment for the PICTIC II boards and I got an >> email back from Bob about getting me on the list for the programmed PICs. > > All you need now is a DMTD and you'll be in a good position to things > like ADEV measurements on your sources. As the Rbs are not great at > close-in ADEV, it would be worth while looking for the dual-oven HP > 10811. > >> That's where I'm at right now. > > Well, your doing OK. > > 73 de Steve ZL3TUV & G8KVD > >> 73 Brice KA8
Re: [time-nuts] HP 5061A on auction 290458191620
>> with a cal lab for defence department contracts Or maybe they don't have the ability to check for output :-) On Tue, Jul 27, 2010 at 7:04 AM, swingbyte wrote: > On 27/07/2010 11:16 PM, paul swed wrote: >> >> it is funny. But maybe those options did turn it into a network analyzer. >> Powers up untested $1300 AU. Well thats a great gamble for those with >> spare >> cash. >> >> On Tue, Jul 27, 2010 at 9:03 AM, Javier >> Herrerowrote: >> >>> I've enjoyed the description. Particularly the "These atoms are processed >>> is such a way that they become an atomic frequency standard" :) Also the >>> history section... and the characteristics (Frequency Accuracy: +/-5 ppm >>> <--- a little bad for a cesium, right? ;) or Frequency Range: 300KHz – >>> 1.5GHz<--- not so bad... ) So I don't know if option 3 and 4 refers to >>> the >>> 5061A or to the network analyzer specifications from which the seller >>> seems >>> to have messed at writing the description. >>> >>> Regards, >>> >>> Javier >>> >>> El 27/07/2010 12:37, Mark Stephens escribió: >>> >>> 5061A opt 3 and opt 4 Ebay# 290458191620 Not mine but wish it was. Mark VK2HMC ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. >>> -- >>> >>> Javier Herrero EMAIL: jherr...@hvsistemas.com >>> HV Sistemas S.L. PHONE: +34 949 336 806 >>> Los Charcones, 17 FAX: +34 949 336 792 >>> 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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. >> > The seller runs a real store as well as a cal lab for defence department > contracts - so should be able to test. That they don't test it suggests > that they may be are covering for selling an inoperative item or they can't > afford the time to test it. In Australia these are rare and would only come > from the dod which has recently shut down and outsourced its cal labs. or > telecom. Either way its old and overpriced. I 'd like to know how the > other ones they have sold ended up? > They may have been on continuously for 30 years. > > > > > > > > ___ > time-nuts mailing 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] Heathkid - New time-nut needs help...
Kia Ora Brice, On 27/07/2010, Heathkid wrote: > Yes, the FEI 5680A's I got are programmable from 1Hz to 20MHz (SMA output / > currently set to 10MHz) plus has the RS232 for programming and one of those > pins (besides the Rb lock pin that goes low and I've got a LED on it) has > the 1pps. Besides the "C" field potentiometer it also has a 0 to 5V fine > tune voltage. The slowest of the three takes only about 4 seconds to > achieve Rb lock. Here are the exact units I got (and "flyingbest" is a > great and honest seller): > http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180435915714 Not the cheapest I have seen but at least you have a full kit and they are the programmable ones. What's the PSU like, how good is the regulation on it as this will have a factor on how clean the output is. Monitor the voltage at startup right through to it running stable and see if it changes. There seems to be no requirement for +5V for programming the device in the listing you quote but others have indicated that this needs to be connected to pin 4 of the DB-9. That being said, the info I have, http://www.mail-archive.com/time-nuts@febo.com/msg01569.html, does not show a C field adjustment on pin 8. The SMA connector looks like it has been retrofitted IMHO so it would be interesting to pop the hood and look for any mods done by the seller. > The Thunderbolt I bought from fluke.l as he seems to be the "TBolt seller of > choice" around here. I also got the LCD display option (looks like fun to > see what it's doing when not connected to a PC). Yes, I'm yet to get one of those LCD displays although there is quite a discussion thread on these in the archives and you can see the background to this. Before you put the LCD display on for long term use, I suggest you run it with Lady Heather to see how it it is tracking sats and stabilising. The tuning of the PLL constants is the subject of quite a few threads in the archives so you can learn a lot from that. Once your happy that it's running fine, connect the LCD display but I'd run it for a few weeks before you get to that stage as the ocxo will have been sitting on the shelf cold and you want to see how that is shaping up (this will take months before the xo really beds in). You should also keep an eye on it continuing to track sats as some people have found that their TB's have completely lost the plot at times. When you first start it up it won't know what the heck is going on as the location it was last running will be internally stored and it will be looking for sats in the sky and not seeing them. You should make sure it does a survey straight away so that sanity is restored and/or you can enter your exact location of the antenna if you know that. I don't know your location but you should make sure that your antenna is located in a good position where it has a good sight to the south and look out for multipath reception, trees, buildings, etc. but your a ham anyway and must be in a good position to fix it up as your doing QRP. > Okay, so today... I bought a "real" frequency counter. After a LOT of > looking and reading... I chose a HP 5335A. It has option 10 (Oven > Oscillator) and 030 (C Channel 1.3 GHz ) plus the HPIB plus math and > statistics functions standard and includes operating and service manuals on > CD. It'll also be calibrated just prior to shipping to me (current Date Due > 03/19/11) but it will be re-calibrated just for me so at least I know it'll > work and if there is a problem, I can return it. :) Well, that's a nice purchase and I'm sure it will serve you well. > So, now I have the following (when the rest shows up): > > (3) FEI 5680A Programmable Rubidium Frequency Standards w/ 1pps > (1) Thunderbolt "Complete Kit" w/ LCD display - from fluke.l > (1) HP 5335A Universal Counter w/ Options 10 (Oven Oscillator) & 030 (C > Channel 1.3 GHz) Well, that's a start, or should I say, the slippery slope :) You'll have a good setup with this and have a decent frequency standard for your lab equipment. You can program those 5680A's to output directly on some of the HF bands and have a Rb controlled QRP rig :) > Hopefully, Stanley got my payment for the PICTIC II boards and I got an > email back from Bob about getting me on the list for the programmed PICs. All you need now is a DMTD and you'll be in a good position to things like ADEV measurements on your sources. As the Rbs are not great at close-in ADEV, it would be worth while looking for the dual-oven HP 10811. > That's where I'm at right now. Well, your doing OK. 73 de Steve ZL3TUV & G8KVD > 73 Brice KA8MAV > > > > - Original Message - > From: "Steve Rooke" > To: "Discussion of precise time and frequency measurement" > > Sent: Monday, July 26, 2010 7:54 AM > Subject: Re: [time-nuts] Symmetricom X72 > > >> Yes, it's because of the various types that you need to verify exactly >> what you have. A number of them are made to customer specifications >> with undocumented option numb
Re: [time-nuts] Pictic II boards are here !
Board received 7/26/10, nice looking board, thanks for the order. Regards, Bob Martinson -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Stanley Reynolds Sent: Tuesday, July 20, 2010 6:08 PM To: time-nuts@febo.com Subject: [time-nuts] Pictic II boards are here ! Paypal to stanley_reyno...@yahoo.com . Yes I still have extra boards. 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.
Re: [time-nuts] Sale TRACOR527E
Hi, Is the manual for the 527E or for the 527A? AFAIK, the difference is only 1 card but there are no drawings of that card available. It would be a real public service to scan or copy it before selling your unit. If you have a real 527E manual copy, please contact me off-list. Thanks, -John = > > Hi all, > For sale Tracor 527E frequency difference meter. Accept 1,5,10 Mhz > perfectly working come with manual copy.One front handle is missing. Price > 350,00 Euros > Shipping from Italy not included. Paypal account or Poste Pay if in Italy. > If interested replay writing your personal email address.I will contact > you directly. > Thanks all you, > Luciano > IZ5JHJ > ___ > time-nuts mailing 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] Pictic assembled pictures
Here: www.n4iqt.com/picticii/assembled I think it would be possible to use the side adjust square trimmers but not the rectangular ones as they are too big and the holes would be too far apart to mount them close to the board. The top adjust would be the first choice because they would be easier adjust especially if board is mounted in a case. 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] Fury - Rubidium
Has anybody on the list interfaced a Fury GPS controller to a rubidium ? If you have, please advise the rubidium are using and your SERV:DACG , SERV:EFCS , and SERV:EFCD settings. I am working with a FRS-C at the moment and I have not found the right combination to get a stable lock. Thanks - Brian KD4FM ___ time-nuts mailing 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] HP 5061A on auction 290458191620
On 27/07/2010 11:16 PM, paul swed wrote: it is funny. But maybe those options did turn it into a network analyzer. Powers up untested $1300 AU. Well thats a great gamble for those with spare cash. On Tue, Jul 27, 2010 at 9:03 AM, Javier Herrerowrote: I've enjoyed the description. Particularly the "These atoms are processed is such a way that they become an atomic frequency standard" :) Also the history section... and the characteristics (Frequency Accuracy: +/-5 ppm <--- a little bad for a cesium, right? ;) or Frequency Range: 300KHz – 1.5GHz<--- not so bad... ) So I don't know if option 3 and 4 refers to the 5061A or to the network analyzer specifications from which the seller seems to have messed at writing the description. Regards, Javier El 27/07/2010 12:37, Mark Stephens escribió: 5061A opt 3 and opt 4 Ebay# 290458191620 Not mine but wish it was. Mark VK2HMC ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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. The seller runs a real store as well as a cal lab for defence department contracts - so should be able to test. That they don't test it suggests that they may be are covering for selling an inoperative item or they can't afford the time to test it. In Australia these are rare and would only come from the dod which has recently shut down and outsourced its cal labs. or telecom. Either way its old and overpriced. I 'd like to know how the other ones they have sold ended up? They may have been on continuously for 30 years. ___ time-nuts mailing 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] HP 5061A on auction 290458191620
it is funny. But maybe those options did turn it into a network analyzer. Powers up untested $1300 AU. Well thats a great gamble for those with spare cash. On Tue, Jul 27, 2010 at 9:03 AM, Javier Herrero wrote: > I've enjoyed the description. Particularly the "These atoms are processed > is such a way that they become an atomic frequency standard" :) Also the > history section... and the characteristics (Frequency Accuracy: +/-5 ppm > <--- a little bad for a cesium, right? ;) or Frequency Range: 300KHz – > 1.5GHz <--- not so bad... ) So I don't know if option 3 and 4 refers to the > 5061A or to the network analyzer specifications from which the seller seems > to have messed at writing the description. > > Regards, > > Javier > > El 27/07/2010 12:37, Mark Stephens escribió: > > 5061A opt 3 and opt 4 >> >> Ebay# 290458191620 >> >> Not mine but wish it was. >> >> >> Mark >> VK2HMC >> >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > -- > > Javier HerreroEMAIL: jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 806 > Los Charcones, 17 FAX: +34 949 336 792 > 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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] HP 5061A on auction 290458191620
I've enjoyed the description. Particularly the "These atoms are processed is such a way that they become an atomic frequency standard" :) Also the history section... and the characteristics (Frequency Accuracy: +/-5 ppm <--- a little bad for a cesium, right? ;) or Frequency Range: 300KHz – 1.5GHz <--- not so bad... ) So I don't know if option 3 and 4 refers to the 5061A or to the network analyzer specifications from which the seller seems to have messed at writing the description. Regards, Javier El 27/07/2010 12:37, Mark Stephens escribió: 5061A opt 3 and opt 4 Ebay# 290458191620 Not mine but wish it was. Mark VK2HMC ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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] HP 5061A on auction 290458191620
5061A opt 3 and opt 4 Ebay# 290458191620 Not mine but wish it was. Mark VK2HMC ___ time-nuts mailing 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] Basic question regarding comparing two frequencies
On Tue, 27 Jul 2010 09:08:49 am Chuck Harris wrote: > I suppose that you could always cheat? Since you know where the > transmitter is going to be, if you could get a timenut near to the > transmitter to give you a beacon to measure 24hrs prior to the event, > you could use the diurnal variations that you observed (observe?) on > the beacon to predict the skywave offset due to Doppler at the time > of the event. > > -Chuck Harris > > Murray Greenman wrote: > > You guys are trying to crack a nut with a sledgehammer! > > > > For a start, as Didier says, you can't possibly read the frequency of a > > sky-wave signal to 0.01Hz in any short time frame since the Doppler on > > the signal can be as much as 1ppm (i.e. 10Hz at 10MHz). You can only > > infer it closer than that by studying the frequency in the very long > > term. > > > > In addition, you'll never know how much of the daily variation is > > ionospheric, and how much is due to thermal changes at the source. snipped There is one possible way of getting an accurate reading from a sky wave signal over a short(ish) period. Plot a doppler shift curve with as fine a resolution as you can manage. Then look for a point of inflexion in the curve, that is a point where the second derivative of the curve function is zero. The frequency at that time will be that transmitted as at that instant the path length is not changing. You may have to examine your data set visually and mathematically examine a much smaller section. Of course if you don't get a point of inflexion you'll need much more data :-). Cheers, Geoff vk2tfg. ___ time-nuts mailing 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] Sale TRACOR527E
Hi all, For sale Tracor 527E frequency difference meter. Accept 1,5,10 Mhz perfectly working come with manual copy.One front handle is missing. Price 350,00 Euros Shipping from Italy not included. Paypal account or Poste Pay if in Italy. If interested replay writing your personal email address.I will contact you directly. Thanks all you, Luciano IZ5JHJ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
