Hello Time-Nutters-- I am working on building a downlinking AZ/EL tracking dish set up to receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit meteorological/environmental satellite.  The receiver seems to be working OK but it periodically appears to slowly drift frequency by 300 Hz to 400 Hz.  I need some way to accurately determine what the actual RX receive frequency is. I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. I originally got it thinking that it would provide a decent phase-lock reference for my freq-counters, o-scopes, spectrum analyzers and Agilent/HP vector network analyzer. The only other item I have that has (or should have) a reasonably accurate 10 MHz reference output is a Trimble Thunderbolt. However, there is a several hundred Hz freq difference between the Efratom and the Trimble T-bolt. My question is how do I go confirming the frequency of the T-Bolt or the Efratom Rubidium?  The Efratom has an adjustment pot to fine-tune its output frequency.  How do Time-Nutters go about confirming the accuracy of frequency references such as my T-Bolt or Efratom rubidium oscillator? Thanks for any feedback / suggestions on this !! Off-list communications on this via my email is OK!! Mike Baker   mpb45@clanbaker.org Micanopy/Gainesville  North Central Florida **********************

Hi If the TBolt is locked up and has stayed locked up for 24 hours it should be pretty accurate. Ideally you would like to be locked to at least 4 sats at all times for best accuracy. Lady Heather is your friend when it comes to checking this sort of thing. How good is “pretty accurate”? At 8 GHz, it’s a good bet ( 99 %) that you are under 1 Hz of error. It’s a reasonable bet (> 80%) that you are under 0.1 Hz. Both assume a 100 second gate on your counter. Things degrade a bit if you go to shorter gate times. The numbers above are conservative for most TBolts. The Efratom drifts (ages) enough that a 300 Hz error at 8 GHz is not impossible. A lot depends on just how long it’s been since it last was set on frequency. Most examples are not that far off frequency …. Neither the TBolt *or* the LPRO should “drift” 300 to 400 Hz at 8 GHz over any reasonable amount of time ( hours, days, weeks). This assumes they stay powered up and in the TBolt’s case, locked to >4 sats. What to do? Best guess is the TBolt is right and the LPRO is wrong. Reset the LPRO so it agrees with the TBolt. Bob > On Aug 21, 2021, at 8:50 AM, mpb45@clanbaker.org wrote: > > Hello Time-Nutters-- > > I am working on building a downlinking AZ/EL tracking dish set up to > receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit > meteorological/environmental satellite. The receiver seems to be > working OK but it periodically appears to slowly drift frequency by > 300 Hz to 400 Hz. I need some way to accurately determine what > the actual RX receive frequency is. > > I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. > I originally got it thinking that it would provide a decent > phase-lock reference for my freq-counters, o-scopes, spectrum > analyzers and Agilent/HP vector network analyzer. > > The only other item I have that has (or should have) a reasonably > accurate 10 MHz reference output is a Trimble Thunderbolt. > However, there is a several hundred Hz freq difference between the > Efratom and the Trimble T-bolt. > > My question is how do I go confirming the frequency of the T-Bolt > or the Efratom Rubidium? The Efratom has an adjustment pot > to fine-tune its output frequency. How do Time-Nutters go about > confirming the accuracy of frequency references such as my > T-Bolt or Efratom rubidium oscillator? > > Thanks for any feedback / suggestions on this !! > > Off-list communications on this via my email is OK!! > > Mike Baker mpb45@clanbaker.org > Micanopy/Gainesville North Central Florida > ********************** > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

Hi, a Rb will not be long-term accurate. I'd trust a GPSDO to be long-term accurate. A hundreds-of-Hz offset between the LPRO and the GPSDO certainly points into the direction of the LPRO being off the mark. When you adjust the LPRO, be sure to give it ample time to stabilize. BR, Matthias On Samstag, 21. August 2021 14:50:24 CEST mpb45@clanbaker.org wrote: > Hello Time-Nutters-- > > I am working on building a downlinking AZ/EL tracking dish set up to > receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit > meteorological/environmental satellite. The receiver seems to be > working OK but it periodically appears to slowly drift frequency by > 300 Hz to 400 Hz. I need some way to accurately determine what > the actual RX receive frequency is. > > I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. > I originally got it thinking that it would provide a decent > phase-lock reference for my freq-counters, o-scopes, spectrum > analyzers and Agilent/HP vector network analyzer. > > The only other item I have that has (or should have) a reasonably > accurate 10 MHz reference output is a Trimble Thunderbolt. > However, there is a several hundred Hz freq difference between the > Efratom and the Trimble T-bolt. > > My question is how do I go confirming the frequency of the T-Bolt > or the Efratom Rubidium? The Efratom has an adjustment pot > to fine-tune its output frequency. How do Time-Nutters go about > confirming the accuracy of frequency references such as my > T-Bolt or Efratom rubidium oscillator? > > Thanks for any feedback / suggestions on this !! > > Off-list communications on this via my email is OK!! > > Mike Baker mpb45@clanbaker.org > Micanopy/Gainesville North Central Florida > ********************** > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow > the instructions there.

C'mon guys- when you speak of a frequency error in Hz, you should also specify "at what frequency" *in the same breath*. Or better yet, always specify frequency errors in relative terms. Hundreds of Hz at 10 Mhz is unthinkable for a Rb. Even at 8.2 GHz, 100 Hz error is about 12E-9, which is likely to be outside the EFC tuning range of some (if not most) Rb standards. Both of my Rbs have a tuning range of only roughly 2E-9 via the EFC input. Outside that range, much sterner measures must be taken, which I frankly dread. The two Rbs that I own (an L-Pro and a PRS-10) both tend to drift upwards in frequency to the tune of about 1E-11 or 2E-11 per month. Superimposed on that are random variations of around 1E-11 on a time scale of a few hours. I make phase comparisons between the 10 MHz outputs of a GPSDO and the Rb under test using a simple quadrature demodulator, with the I & Q outputs displayed on a 2-chan DSO. I use the "roll mode" display feature on the DSO at its slowest speed (1000 sec/div) and just leave things running continuously for up to several days. On my DSO a full screen width is 14000 sec (slightly under 4 hours), and I just take a glance from time to time as I happen to pass by. Someone suggested a 100 sec measurement with a counter, but that is right in the realm where GPSDOs are typically the most noisy, so a single measurement is likely to have rather large errors. One would have to record a fairly large number of such measurements (several hundreds of them) and plot them out to get a good assessment of what the Rb is actually doing. WIth the IQ phase difference display, one can get a pretty decent estimate of the needed tuning correction, without doing any real work at all, in a day or so. When I'm doing something requiring the best frequency accuracy, I keep the 'scope display running while I'm doing the serious work, and note the frequency error of the Rb at the time for use in correcting the final result. BTW, I don't see much "settling" effect after making tuning changes- the correction made seems to take effect essentially immediately (as best as one can tell in the presence of GPS noise). By comparing two Rbs, I can investigate settling effects quite well without the noise having anything to do with it. Dana On Sun, Aug 22, 2021 at 8:41 AM Matthias Welwarsky <time-nuts@welwarsky.de> wrote: > Hi, > > a Rb will not be long-term accurate. I'd trust a GPSDO to be long-term > accurate. A hundreds-of-Hz offset between the LPRO and the GPSDO certainly > points into the direction of the LPRO being off the mark. > > When you adjust the LPRO, be sure to give it ample time to stabilize. > > BR, > Matthias > > On Samstag, 21. August 2021 14:50:24 CEST mpb45@clanbaker.org wrote: > > Hello Time-Nutters-- > > > > I am working on building a downlinking AZ/EL tracking dish set up to > > receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit > > meteorological/environmental satellite. The receiver seems to be > > working OK but it periodically appears to slowly drift frequency by > > 300 Hz to 400 Hz. I need some way to accurately determine what > > the actual RX receive frequency is. > > > > I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. > > I originally got it thinking that it would provide a decent > > phase-lock reference for my freq-counters, o-scopes, spectrum > > analyzers and Agilent/HP vector network analyzer. > > > > The only other item I have that has (or should have) a reasonably > > accurate 10 MHz reference output is a Trimble Thunderbolt. > > However, there is a several hundred Hz freq difference between the > > Efratom and the Trimble T-bolt. > > > > My question is how do I go confirming the frequency of the T-Bolt > > or the Efratom Rubidium? The Efratom has an adjustment pot > > to fine-tune its output frequency. How do Time-Nutters go about > > confirming the accuracy of frequency references such as my > > T-Bolt or Efratom rubidium oscillator? > > > > Thanks for any feedback / suggestions on this !! > > > > Off-list communications on this via my email is OK!! > > > > Mike Baker mpb45@clanbaker.org > > Micanopy/Gainesville North Central Florida > > ********************** > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an > > email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow > > the instructions there. > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there. >

Dana, >I make phase comparisons between the 10 MHz outputs of a GPSDO and the Rb >under test using a simple quadrature demodulator, with the I & Q outputs >displayed on a 2-chan DSO. Can you explain what you do? Do you just connect the two 10 MHz signals to the input of the demodulator? Robert On 08/22/2021 11:16 AM, Dana Whitlow wrote: > C'mon guys- when you speak of a frequency error in Hz, you should also > specify "at > what frequency" *in the same breath*. Or better yet, always specify > frequency errors in > relative terms. > > Hundreds of Hz at 10 Mhz is unthinkable for a Rb. Even at 8.2 GHz, 100 Hz > error is about > 12E-9, which is likely to be outside the EFC tuning range of some (if not > most) Rb standards. > Both of my Rbs have a tuning range of only roughly 2E-9 via the EFC input. > Outside that > range, much sterner measures must be taken, which I frankly dread. > > The two Rbs that I own (an L-Pro and a PRS-10) both tend to drift upwards > in frequency > to the tune of about 1E-11 or 2E-11 per month. Superimposed on that are > random > variations of around 1E-11 on a time scale of a few hours. > > I make phase comparisons between the 10 MHz outputs of a GPSDO and the Rb > under > test using a simple quadrature demodulator, with the I & Q outputs > displayed on a 2-chan > DSO. I use the "roll mode" display feature on the DSO at its slowest speed > (1000 sec/div) > and just leave things running continuously for up to several days. On my > DSO a full screen > width is 14000 sec (slightly under 4 hours), and I just take a glance from > time to time as I > happen to pass by. > > Someone suggested a 100 sec measurement with a counter, but that is right > in the realm > where GPSDOs are typically the most noisy, so a single measurement is > likely to have > rather large errors. One would have to record a fairly large number of > such measurements > (several hundreds of them) and plot them out to get a good assessment of > what the Rb is > actually doing. WIth the IQ phase difference display, one can get a pretty > decent estimate of > the needed tuning correction, without doing any real work at all, in a day > or so. > > When I'm doing something requiring the best frequency accuracy, I keep the > 'scope display > running while I'm doing the serious work, and note the frequency error of > the Rb at the time > for use in correcting the final result. BTW, I don't see much "settling" > effect after making > tuning changes- the correction made seems to take effect essentially > immediately (as best > as one can tell in the presence of GPS noise). By comparing two Rbs, I can > investigate > settling effects quite well without the noise having anything to do with it. > > Dana > > > On Sun, Aug 22, 2021 at 8:41 AM Matthias Welwarsky <time-nuts@welwarsky.de> > wrote: > >> Hi, >> >> a Rb will not be long-term accurate. I'd trust a GPSDO to be long-term >> accurate. A hundreds-of-Hz offset between the LPRO and the GPSDO certainly >> points into the direction of the LPRO being off the mark. >> >> When you adjust the LPRO, be sure to give it ample time to stabilize. >> >> BR, >> Matthias >> >> On Samstag, 21. August 2021 14:50:24 CEST mpb45@clanbaker.org wrote: >>> Hello Time-Nutters-- >>> >>> I am working on building a downlinking AZ/EL tracking dish set up to >>> receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit >>> meteorological/environmental satellite. The receiver seems to be >>> working OK but it periodically appears to slowly drift frequency by >>> 300 Hz to 400 Hz. I need some way to accurately determine what >>> the actual RX receive frequency is. >>> >>> I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. >>> I originally got it thinking that it would provide a decent >>> phase-lock reference for my freq-counters, o-scopes, spectrum >>> analyzers and Agilent/HP vector network analyzer. >>> >>> The only other item I have that has (or should have) a reasonably >>> accurate 10 MHz reference output is a Trimble Thunderbolt. >>> However, there is a several hundred Hz freq difference between the >>> Efratom and the Trimble T-bolt. >>> >>> My question is how do I go confirming the frequency of the T-Bolt >>> or the Efratom Rubidium? The Efratom has an adjustment pot >>> to fine-tune its output frequency. How do Time-Nutters go about >>> confirming the accuracy of frequency references such as my >>> T-Bolt or Efratom rubidium oscillator? >>> >>> Thanks for any feedback / suggestions on this !! >>> >>> Off-list communications on this via my email is OK!! >>> >>> Mike Baker mpb45@clanbaker.org >>> Micanopy/Gainesville North Central Florida >>> ********************** >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe >> send an >>> email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow >>> the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send >> an email to time-nuts-leave@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there. >

I connect one signal to the LO input of the demodulator, and the other signal to the RF input. I should draw up a schematic of this, and will do so. Dana On Mon, Aug 23, 2021 at 4:59 PM Robert DiRosario <ka3zyx@comcast.net> wrote: > Dana, > > >I make phase comparisons between the 10 MHz outputs of a GPSDO and the Rb > >under test using a simple quadrature demodulator, with the I & Q outputs > >displayed on a 2-chan DSO. > > Can you explain what you do? Do you just connect the two 10 MHz signals > to the input of the demodulator? > > Robert > > > On 08/22/2021 11:16 AM, Dana Whitlow wrote: > > C'mon guys- when you speak of a frequency error in Hz, you should also > > specify "at > > what frequency" *in the same breath*. Or better yet, always specify > > frequency errors in > > relative terms. > > > > Hundreds of Hz at 10 Mhz is unthinkable for a Rb. Even at 8.2 GHz, 100 > Hz > > error is about > > 12E-9, which is likely to be outside the EFC tuning range of some (if not > > most) Rb standards. > > Both of my Rbs have a tuning range of only roughly 2E-9 via the EFC > input. > > Outside that > > range, much sterner measures must be taken, which I frankly dread. > > > > The two Rbs that I own (an L-Pro and a PRS-10) both tend to drift upwards > > in frequency > > to the tune of about 1E-11 or 2E-11 per month. Superimposed on that are > > random > > variations of around 1E-11 on a time scale of a few hours. > > > > I make phase comparisons between the 10 MHz outputs of a GPSDO and the Rb > > under > > test using a simple quadrature demodulator, with the I & Q outputs > > displayed on a 2-chan > > DSO. I use the "roll mode" display feature on the DSO at its slowest > speed > > (1000 sec/div) > > and just leave things running continuously for up to several days. On my > > DSO a full screen > > width is 14000 sec (slightly under 4 hours), and I just take a glance > from > > time to time as I > > happen to pass by. > > > > Someone suggested a 100 sec measurement with a counter, but that is right > > in the realm > > where GPSDOs are typically the most noisy, so a single measurement is > > likely to have > > rather large errors. One would have to record a fairly large number of > > such measurements > > (several hundreds of them) and plot them out to get a good assessment of > > what the Rb is > > actually doing. WIth the IQ phase difference display, one can get a > pretty > > decent estimate of > > the needed tuning correction, without doing any real work at all, in a > day > > or so. > > > > When I'm doing something requiring the best frequency accuracy, I keep > the > > 'scope display > > running while I'm doing the serious work, and note the frequency error of > > the Rb at the time > > for use in correcting the final result. BTW, I don't see much "settling" > > effect after making > > tuning changes- the correction made seems to take effect essentially > > immediately (as best > > as one can tell in the presence of GPS noise). By comparing two Rbs, I > can > > investigate > > settling effects quite well without the noise having anything to do with > it. > > > > Dana > > > > > > On Sun, Aug 22, 2021 at 8:41 AM Matthias Welwarsky < > time-nuts@welwarsky.de> > > wrote: > > > >> Hi, > >> > >> a Rb will not be long-term accurate. I'd trust a GPSDO to be long-term > >> accurate. A hundreds-of-Hz offset between the LPRO and the GPSDO > certainly > >> points into the direction of the LPRO being off the mark. > >> > >> When you adjust the LPRO, be sure to give it ample time to stabilize. > >> > >> BR, > >> Matthias > >> > >> On Samstag, 21. August 2021 14:50:24 CEST mpb45@clanbaker.org wrote: > >>> Hello Time-Nutters-- > >>> > >>> I am working on building a downlinking AZ/EL tracking dish set up to > >>> receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit > >>> meteorological/environmental satellite. The receiver seems to be > >>> working OK but it periodically appears to slowly drift frequency by > >>> 300 Hz to 400 Hz. I need some way to accurately determine what > >>> the actual RX receive frequency is. > >>> > >>> I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. > >>> I originally got it thinking that it would provide a decent > >>> phase-lock reference for my freq-counters, o-scopes, spectrum > >>> analyzers and Agilent/HP vector network analyzer. > >>> > >>> The only other item I have that has (or should have) a reasonably > >>> accurate 10 MHz reference output is a Trimble Thunderbolt. > >>> However, there is a several hundred Hz freq difference between the > >>> Efratom and the Trimble T-bolt. > >>> > >>> My question is how do I go confirming the frequency of the T-Bolt > >>> or the Efratom Rubidium? The Efratom has an adjustment pot > >>> to fine-tune its output frequency. How do Time-Nutters go about > >>> confirming the accuracy of frequency references such as my > >>> T-Bolt or Efratom rubidium oscillator? > >>> > >>> Thanks for any feedback / suggestions on this !! > >>> > >>> Off-list communications on this via my email is OK!! > >>> > >>> Mike Baker mpb45@clanbaker.org > >>> Micanopy/Gainesville North Central Florida > >>> ********************** > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > >> send an > >>> email to time-nuts-leave@lists.febo.com To unsubscribe, go to and > follow > >>> the instructions there. > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send > >> an email to time-nuts-leave@lists.febo.com > >> To unsubscribe, go to and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there. >

On Dienstag, 24. August 2021 00:00:41 CEST Dana Whitlow wrote: > I connect one signal to the LO input of the demodulator, and the other > signal to the > RF input. I should draw up a schematic of this, and will do so. It's basically "half" of a DMTD, an "SMTD", so to speak, but without the "difference" part ;) > > Dana > > On Mon, Aug 23, 2021 at 4:59 PM Robert DiRosario <ka3zyx@comcast.net> wrote: > > Dana, > > > > >I make phase comparisons between the 10 MHz outputs of a GPSDO and the Rb > > >under test using a simple quadrature demodulator, with the I & Q outputs > > >displayed on a 2-chan DSO. > > > > Can you explain what you do? Do you just connect the two 10 MHz signals > > to the input of the demodulator? > > > > Robert > > > > On 08/22/2021 11:16 AM, Dana Whitlow wrote: > > > C'mon guys- when you speak of a frequency error in Hz, you should also > > > specify "at > > > what frequency" *in the same breath*. Or better yet, always specify > > > frequency errors in > > > relative terms. > > > > > > Hundreds of Hz at 10 Mhz is unthinkable for a Rb. Even at 8.2 GHz, 100 > > > > Hz > > > > > error is about > > > 12E-9, which is likely to be outside the EFC tuning range of some (if > > > not > > > most) Rb standards. > > > Both of my Rbs have a tuning range of only roughly 2E-9 via the EFC > > > > input. > > > > > Outside that > > > range, much sterner measures must be taken, which I frankly dread. > > > > > > The two Rbs that I own (an L-Pro and a PRS-10) both tend to drift > > > upwards > > > in frequency > > > to the tune of about 1E-11 or 2E-11 per month. Superimposed on that are > > > random > > > variations of around 1E-11 on a time scale of a few hours. > > > > > > I make phase comparisons between the 10 MHz outputs of a GPSDO and the > > > Rb > > > under > > > test using a simple quadrature demodulator, with the I & Q outputs > > > displayed on a 2-chan > > > DSO. I use the "roll mode" display feature on the DSO at its slowest > > > > speed > > > > > (1000 sec/div) > > > and just leave things running continuously for up to several days. On > > > my > > > DSO a full screen > > > width is 14000 sec (slightly under 4 hours), and I just take a glance > > > > from > > > > > time to time as I > > > happen to pass by. > > > > > > Someone suggested a 100 sec measurement with a counter, but that is > > > right > > > in the realm > > > where GPSDOs are typically the most noisy, so a single measurement is > > > likely to have > > > rather large errors. One would have to record a fairly large number of > > > such measurements > > > (several hundreds of them) and plot them out to get a good assessment of > > > what the Rb is > > > actually doing. WIth the IQ phase difference display, one can get a > > > > pretty > > > > > decent estimate of > > > the needed tuning correction, without doing any real work at all, in a > > > > day > > > > > or so. > > > > > > When I'm doing something requiring the best frequency accuracy, I keep > > > > the > > > > > 'scope display > > > running while I'm doing the serious work, and note the frequency error > > > of > > > the Rb at the time > > > for use in correcting the final result. BTW, I don't see much > > > "settling" > > > effect after making > > > tuning changes- the correction made seems to take effect essentially > > > immediately (as best > > > as one can tell in the presence of GPS noise). By comparing two Rbs, I > > > > can > > > > > investigate > > > settling effects quite well without the noise having anything to do with > > > > it. > > > > > Dana > > > > > > > > > On Sun, Aug 22, 2021 at 8:41 AM Matthias Welwarsky < > > > > time-nuts@welwarsky.de> > > > > > wrote: > > >> Hi, > > >> > > >> a Rb will not be long-term accurate. I'd trust a GPSDO to be long-term > > >> accurate. A hundreds-of-Hz offset between the LPRO and the GPSDO > > > > certainly > > > > >> points into the direction of the LPRO being off the mark. > > >> > > >> When you adjust the LPRO, be sure to give it ample time to stabilize. > > >> > > >> BR, > > >> Matthias > > >> > > >> On Samstag, 21. August 2021 14:50:24 CEST mpb45@clanbaker.org wrote: > > >>> Hello Time-Nutters-- > > >>> > > >>> I am working on building a downlinking AZ/EL tracking dish set up to > > >>> receive the 8.2 GHz telemetry from the Suomi JPSS polar orbit > > >>> meteorological/environmental satellite. The receiver seems to be > > >>> working OK but it periodically appears to slowly drift frequency by > > >>> 300 Hz to 400 Hz. I need some way to accurately determine what > > >>> the actual RX receive frequency is. > > >>> > > >>> I have a vintage Efratom LPRO-101 Rubidium 10 MHz oscillator. > > >>> I originally got it thinking that it would provide a decent > > >>> phase-lock reference for my freq-counters, o-scopes, spectrum > > >>> analyzers and Agilent/HP vector network analyzer. > > >>> > > >>> The only other item I have that has (or should have) a reasonably > > >>> accurate 10 MHz reference output is a Trimble Thunderbolt. > > >>> However, there is a several hundred Hz freq difference between the > > >>> Efratom and the Trimble T-bolt. > > >>> > > >>> My question is how do I go confirming the frequency of the T-Bolt > > >>> or the Efratom Rubidium? The Efratom has an adjustment pot > > >>> to fine-tune its output frequency. How do Time-Nutters go about > > >>> confirming the accuracy of frequency references such as my > > >>> T-Bolt or Efratom rubidium oscillator? > > >>> > > >>> Thanks for any feedback / suggestions on this !! > > >>> > > >>> Off-list communications on this via my email is OK!! > > >>> > > >>> Mike Baker mpb45@clanbaker.org > > >>> Micanopy/Gainesville North Central Florida > > >>> ********************** > > >>> > > >>> _______________________________________________ > > >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > > >> > > >> send an > > >> > > >>> email to time-nuts-leave@lists.febo.com To unsubscribe, go to and > > > > follow > > > > >>> the instructions there. > > >> > > >> _______________________________________________ > > >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > > > > send > > > > >> an email to time-nuts-leave@lists.febo.com > > >> To unsubscribe, go to and follow the instructions there. > > > > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > > > > send an email to time-nuts-leave@lists.febo.com > > > > > To unsubscribe, go to and follow the instructions there. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > > an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow > the instructions there.