Three questions: 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with both supplying 10Mhz and 1PPS, is there a way to combine the outputs or some other technique to improve the short and/or long term performance? 2) I’ve become interested in Rubidium Disciplined Oscillators recently and was now thinking of purchasing one of the PRS-10 that I see on Ebay. If I did that and replaced one of the DOCXOs from one of the Lucent boxes, what impact would this have on the overall performance both with and without (when in hold-over)? Basically, is it worth the money to upgrade one of the boxes to a Rubidium disciplined oscillator assuming the GPS signal is rarely lost? 3) Figuring the PRS-10 will cost around $250 when all is said and done, is there a better option to improve my GPSDO system? I basically use the GPSDO as a reference for any equipment that takes an input. I have no monetary need for a reference, just an interest. Thanks. Jerry

Hi > On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: > > Three questions: > > 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with both supplying 10Mhz and 1PPS, is there a way to combine the outputs or some other technique to improve the short and/or long term performance? You can monitor one against the other. Ideally you would want three GPSDO’s and a monitoring setup. That way you can figure out which of the three has gone bad. > > 2) I’ve become interested in Rubidium Disciplined Oscillators recently and was now thinking of purchasing one of the PRS-10 that I see on Ebay. If I did that and replaced one of the DOCXOs from one of the Lucent boxes, what impact would this have on the overall performance both with and without (when in hold-over)? If you go into holdover, you are the exception. Most setups rarely go into holdover. When they do, it’s because a hurricane just went over the house. Generally that’s not when the focus is going to be on timing experiments. > Basically, is it worth the money to upgrade one of the boxes to a Rubidium disciplined oscillator assuming the GPS signal is rarely lost? Not worth the money if you are only looking at holdover and have a typical setup. > > 3) Figuring the PRS-10 will cost around $250 when all is said and done, is there a better option to improve my GPSDO system? Disciplining implies continuously correcting. Rb standards age much less than a typical OCXO. Oddly enough their temperature stability may not be as good as a high end DOCXO. It is fairly common to try to stabilize the environment your standards operate in. To the extent you are successful this reduces the need to deal with temperature. The net effect is that disciplining an Rb at a rate (filter / control loop / manual tweak) of less than a few days actually makes the Rb worse. Coming up with software to “back off” on the tuning is not as simple as it might seem. This comes back to the fact that the GPS signal (or any of the sat signals) are quite noisy. You need to average them over a *long* time to get good performance. Rb’s are enough better than a GPSDO OCXO that the time ranges really stretch out …. > > I basically use the GPSDO as a reference for any equipment that takes an input. I have no monetary need for a reference, just an interest. For most normal test equipment, a GPSDO output is “plenty good enough”. As a source for fancy timing experiments … maybe not so much. As a phase noise reference or a spur free source for microwave games … also not the best way to go. Bob > > Thanks. > > Jerry > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

I've got several of the Ref 0 boxes but none of the Ref 1. I've added an Oncore GPS receiver to one of them as per Peter Garde's notes and it works well. But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 configuration. Not that I need an HA reference but just for interest. I've only had a quick look so far and found that connecting the two together with a 15-pin cable didn't work. Has anyone looked into this ? On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > > > > On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: > > > > Three questions: > > > > 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with > both supplying 10Mhz and 1PPS, is there a way to combine the outputs or > some other technique to improve the short and/or long term performance? > > You can monitor one against the other. Ideally you would want three > GPSDO’s and a > monitoring setup. That way you can figure out which of the three has gone > bad. > > > > > 2) I’ve become interested in Rubidium Disciplined Oscillators recently > and was now thinking of purchasing one of the PRS-10 that I see on Ebay. If > I did that and replaced one of the DOCXOs from one of the Lucent boxes, > what impact would this have on the overall performance both with and > without (when in hold-over)? > > If you go into holdover, you are the exception. Most setups rarely go into > holdover. When they > do, it’s because a hurricane just went over the house. Generally that’s > not when the focus is going > to be on timing experiments. > > > Basically, is it worth the money to upgrade one of the boxes to a > Rubidium disciplined oscillator assuming the GPS signal is rarely lost? > > Not worth the money if you are only looking at holdover and have a typical > setup. > > > > > 3) Figuring the PRS-10 will cost around $250 when all is said and done, > is there a better option to improve my GPSDO system? > > > Disciplining implies continuously correcting. Rb standards age much less > than a typical > OCXO. Oddly enough their temperature stability may not be as good as a > high end > DOCXO. It is fairly common to try to stabilize the environment your > standards operate in. > To the extent you are successful this reduces the need to deal with > temperature. > > The net effect is that disciplining an Rb at a rate (filter / control loop > / manual tweak) of less than > a few days actually makes the Rb worse. Coming up with software to “back > off” on the tuning is > not as simple as it might seem. > > This comes back to the fact that the GPS signal (or any of the sat > signals) are quite noisy. You > need to average them over a *long* time to get good performance. Rb’s are > enough better than > a GPSDO OCXO that the time ranges really stretch out …. > > > > > I basically use the GPSDO as a reference for any equipment that takes an > input. I have no monetary need for a reference, just an interest. > > For most normal test equipment, a GPSDO output is “plenty good enough”. As > a source for fancy > timing experiments … maybe not so much. As a phase noise reference or a > spur free source for > microwave games … also not the best way to go. > > Bob > > > > > > Thanks. > > > > Jerry > > > > _______________________________________________ > > time-nuts mailing 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 15pin cable has to be cross-connected. Maybe that is your problem? The pin connections were posted not that long ago. It is like 1-15; 2-14; 3-13; 4-12; 5-11; 6-10; 7-9; 8-8; 9-7; 10-6;11-5; etc. > On Nov 22, 2017, at 3:08 PM, Adrian Godwin <artgodwin@gmail.com> wrote: > > I've got several of the Ref 0 boxes but none of the Ref 1. I've added an > Oncore GPS receiver to one of them as per Peter Garde's notes and it works > well. > > But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 > configuration. Not that I need an HA reference but just for interest. I've > only had a quick look so far and found that connecting the two together > with a 15-pin cable didn't work. > > Has anyone looked into this ? > > > On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > >> Hi >> >> >> >>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: >>> >>> Three questions: >>> >>> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with >> both supplying 10Mhz and 1PPS, is there a way to combine the outputs or >> some other technique to improve the short and/or long term performance? >> >> You can monitor one against the other. Ideally you would want three >> GPSDO’s and a >> monitoring setup. That way you can figure out which of the three has gone >> bad. >> >>> >>> 2) I’ve become interested in Rubidium Disciplined Oscillators recently >> and was now thinking of purchasing one of the PRS-10 that I see on Ebay. If >> I did that and replaced one of the DOCXOs from one of the Lucent boxes, >> what impact would this have on the overall performance both with and >> without (when in hold-over)? >> >> If you go into holdover, you are the exception. Most setups rarely go into >> holdover. When they >> do, it’s because a hurricane just went over the house. Generally that’s >> not when the focus is going >> to be on timing experiments. >> >>> Basically, is it worth the money to upgrade one of the boxes to a >> Rubidium disciplined oscillator assuming the GPS signal is rarely lost? >> >> Not worth the money if you are only looking at holdover and have a typical >> setup. >> >>> >>> 3) Figuring the PRS-10 will cost around $250 when all is said and done, >> is there a better option to improve my GPSDO system? >> >> >> Disciplining implies continuously correcting. Rb standards age much less >> than a typical >> OCXO. Oddly enough their temperature stability may not be as good as a >> high end >> DOCXO. It is fairly common to try to stabilize the environment your >> standards operate in. >> To the extent you are successful this reduces the need to deal with >> temperature. >> >> The net effect is that disciplining an Rb at a rate (filter / control loop >> / manual tweak) of less than >> a few days actually makes the Rb worse. Coming up with software to “back >> off” on the tuning is >> not as simple as it might seem. >> >> This comes back to the fact that the GPS signal (or any of the sat >> signals) are quite noisy. You >> need to average them over a *long* time to get good performance. Rb’s are >> enough better than >> a GPSDO OCXO that the time ranges really stretch out …. >> >>> >>> I basically use the GPSDO as a reference for any equipment that takes an >> input. I have no monetary need for a reference, just an interest. >> >> For most normal test equipment, a GPSDO output is “plenty good enough”. As >> a source for fancy >> timing experiments … maybe not so much. As a phase noise reference or a >> spur free source for >> microwave games … also not the best way to go. >> >> Bob >> >> >>> >>> Thanks. >>> >>> Jerry >>> >>> _______________________________________________ >>> time-nuts mailing 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.

Hi I have run a number of the REF0 / REF1 combos. They all seem to work fine. The standard cable has some odd short pins on it. If you are not hot plugging the cable I don’t think they matter at all. If anything, the system is more reliable with a normal length pin on the connector. Bob > On Nov 22, 2017, at 6:08 PM, Adrian Godwin <artgodwin@gmail.com> wrote: > > I've got several of the Ref 0 boxes but none of the Ref 1. I've added an > Oncore GPS receiver to one of them as per Peter Garde's notes and it works > well. > > But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 > configuration. Not that I need an HA reference but just for interest. I've > only had a quick look so far and found that connecting the two together > with a 15-pin cable didn't work. > > Has anyone looked into this ? > > > On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > >> Hi >> >> >> >>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: >>> >>> Three questions: >>> >>> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with >> both supplying 10Mhz and 1PPS, is there a way to combine the outputs or >> some other technique to improve the short and/or long term performance? >> >> You can monitor one against the other. Ideally you would want three >> GPSDO’s and a >> monitoring setup. That way you can figure out which of the three has gone >> bad. >> >>> >>> 2) I’ve become interested in Rubidium Disciplined Oscillators recently >> and was now thinking of purchasing one of the PRS-10 that I see on Ebay. If >> I did that and replaced one of the DOCXOs from one of the Lucent boxes, >> what impact would this have on the overall performance both with and >> without (when in hold-over)? >> >> If you go into holdover, you are the exception. Most setups rarely go into >> holdover. When they >> do, it’s because a hurricane just went over the house. Generally that’s >> not when the focus is going >> to be on timing experiments. >> >>> Basically, is it worth the money to upgrade one of the boxes to a >> Rubidium disciplined oscillator assuming the GPS signal is rarely lost? >> >> Not worth the money if you are only looking at holdover and have a typical >> setup. >> >>> >>> 3) Figuring the PRS-10 will cost around $250 when all is said and done, >> is there a better option to improve my GPSDO system? >> >> >> Disciplining implies continuously correcting. Rb standards age much less >> than a typical >> OCXO. Oddly enough their temperature stability may not be as good as a >> high end >> DOCXO. It is fairly common to try to stabilize the environment your >> standards operate in. >> To the extent you are successful this reduces the need to deal with >> temperature. >> >> The net effect is that disciplining an Rb at a rate (filter / control loop >> / manual tweak) of less than >> a few days actually makes the Rb worse. Coming up with software to “back >> off” on the tuning is >> not as simple as it might seem. >> >> This comes back to the fact that the GPS signal (or any of the sat >> signals) are quite noisy. You >> need to average them over a *long* time to get good performance. Rb’s are >> enough better than >> a GPSDO OCXO that the time ranges really stretch out …. >> >>> >>> I basically use the GPSDO as a reference for any equipment that takes an >> input. I have no monetary need for a reference, just an interest. >> >> For most normal test equipment, a GPSDO output is “plenty good enough”. As >> a source for fancy >> timing experiments … maybe not so much. As a phase noise reference or a >> spur free source for >> microwave games … also not the best way to go. >> >> Bob >> >> >>> >>> Thanks. >>> >>> Jerry >>> >>> _______________________________________________ >>> time-nuts mailing 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.

For the most part the SRS-10 is a nice choice, although I'd always be wary of buying a used one. My only real beefs are that the tuning granularity is rather coarse, about 2E-12, and the disciplining loop seems to be a bit aggressive so that the poor oscillator gets jerked around quite a bit by the GPS. This makes for rather ugly-looking plots of time error over time. The above comments are derived from about 3 years of operating one as a hot emergency spare at the Arecibo Observatory against the day when the H-maser crashed abruptly. In this case the SRS-10 was embedded in an FS725 which we bought new. Dana On Wed, Nov 22, 2017 at 4:16 PM, Jerry Hancock <jerry@hanler.com> wrote: > Three questions: > > 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with > both supplying 10Mhz and 1PPS, is there a way to combine the outputs or > some other technique to improve the short and/or long term performance? > > 2) I’ve become interested in Rubidium Disciplined Oscillators recently and > was now thinking of purchasing one of the PRS-10 that I see on Ebay. If I > did that and replaced one of the DOCXOs from one of the Lucent boxes, what > impact would this have on the overall performance both with and without > (when in hold-over)? Basically, is it worth the money to upgrade one of > the boxes to a Rubidium disciplined oscillator assuming the GPS signal is > rarely lost? > > 3) Figuring the PRS-10 will cost around $250 when all is said and done, is > there a better option to improve my GPSDO system? > > I basically use the GPSDO as a reference for any equipment that takes an > input. I have no monetary need for a reference, just an interest. > > Thanks. > > Jerry > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

Yes, I cross-connected the pins, but I didn't cut any short. On Wed, Nov 22, 2017 at 11:36 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > I have run a number of the REF0 / REF1 combos. They all seem to work fine. > The standard cable has some odd short pins on it. If you are not hot > plugging > the cable I don’t think they matter at all. If anything, the system is > more reliable > with a normal length pin on the connector. > > Bob > > > On Nov 22, 2017, at 6:08 PM, Adrian Godwin <artgodwin@gmail.com> wrote: > > > > I've got several of the Ref 0 boxes but none of the Ref 1. I've added an > > Oncore GPS receiver to one of them as per Peter Garde's notes and it > works > > well. > > > > But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 > > configuration. Not that I need an HA reference but just for interest. > I've > > only had a quick look so far and found that connecting the two together > > with a 15-pin cable didn't work. > > > > Has anyone looked into this ? > > > > > > On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > > > >> Hi > >> > >> > >> > >>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: > >>> > >>> Three questions: > >>> > >>> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with > >> both supplying 10Mhz and 1PPS, is there a way to combine the outputs or > >> some other technique to improve the short and/or long term performance? > >> > >> You can monitor one against the other. Ideally you would want three > >> GPSDO’s and a > >> monitoring setup. That way you can figure out which of the three has > gone > >> bad. > >> > >>> > >>> 2) I’ve become interested in Rubidium Disciplined Oscillators recently > >> and was now thinking of purchasing one of the PRS-10 that I see on > Ebay. If > >> I did that and replaced one of the DOCXOs from one of the Lucent boxes, > >> what impact would this have on the overall performance both with and > >> without (when in hold-over)? > >> > >> If you go into holdover, you are the exception. Most setups rarely go > into > >> holdover. When they > >> do, it’s because a hurricane just went over the house. Generally that’s > >> not when the focus is going > >> to be on timing experiments. > >> > >>> Basically, is it worth the money to upgrade one of the boxes to a > >> Rubidium disciplined oscillator assuming the GPS signal is rarely lost? > >> > >> Not worth the money if you are only looking at holdover and have a > typical > >> setup. > >> > >>> > >>> 3) Figuring the PRS-10 will cost around $250 when all is said and done, > >> is there a better option to improve my GPSDO system? > >> > >> > >> Disciplining implies continuously correcting. Rb standards age much less > >> than a typical > >> OCXO. Oddly enough their temperature stability may not be as good as a > >> high end > >> DOCXO. It is fairly common to try to stabilize the environment your > >> standards operate in. > >> To the extent you are successful this reduces the need to deal with > >> temperature. > >> > >> The net effect is that disciplining an Rb at a rate (filter / control > loop > >> / manual tweak) of less than > >> a few days actually makes the Rb worse. Coming up with software to “back > >> off” on the tuning is > >> not as simple as it might seem. > >> > >> This comes back to the fact that the GPS signal (or any of the sat > >> signals) are quite noisy. You > >> need to average them over a *long* time to get good performance. Rb’s > are > >> enough better than > >> a GPSDO OCXO that the time ranges really stretch out …. > >> > >>> > >>> I basically use the GPSDO as a reference for any equipment that takes > an > >> input. I have no monetary need for a reference, just an interest. > >> > >> For most normal test equipment, a GPSDO output is “plenty good enough”. > As > >> a source for fancy > >> timing experiments … maybe not so much. As a phase noise reference or a > >> spur free source for > >> microwave games … also not the best way to go. > >> > >> Bob > >> > >> > >>> > >>> Thanks. > >>> > >>> Jerry > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@febo.com > >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >> mailman/listinfo/time-nuts > >>> and follow the instructions there. > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >> mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

Adrian, when you stated it didn’t work, what were the results? I had mine running in HA mode, if you can call it that, because only one has a GPS. Actually now that I think about it, the separate but modified REF0 and modified REF1, assuming separate power and antennas, is probably closer to HA than the original application. I have both mine running now with Lady Heather tracking each and I’ve been playing around with comparisons. Now in my case, if either goes down for any reason the other can take over. I guess in order to make them truly HA, we would need a diode or relay switched transfer to the active unit. Jerry > On Nov 22, 2017, at 4:10 PM, Adrian Godwin <artgodwin@gmail.com> wrote: > > Yes, I cross-connected the pins, but I didn't cut any short. > > > > On Wed, Nov 22, 2017 at 11:36 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > >> Hi >> >> I have run a number of the REF0 / REF1 combos. They all seem to work fine. >> The standard cable has some odd short pins on it. If you are not hot >> plugging >> the cable I don’t think they matter at all. If anything, the system is >> more reliable >> with a normal length pin on the connector. >> >> Bob >> >>> On Nov 22, 2017, at 6:08 PM, Adrian Godwin <artgodwin@gmail.com> wrote: >>> >>> I've got several of the Ref 0 boxes but none of the Ref 1. I've added an >>> Oncore GPS receiver to one of them as per Peter Garde's notes and it >> works >>> well. >>> >>> But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 >>> configuration. Not that I need an HA reference but just for interest. >> I've >>> only had a quick look so far and found that connecting the two together >>> with a 15-pin cable didn't work. >>> >>> Has anyone looked into this ? >>> >>> >>> On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: >>> >>>> Hi >>>> >>>> >>>> >>>>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: >>>>> >>>>> Three questions: >>>>> >>>>> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with >>>> both supplying 10Mhz and 1PPS, is there a way to combine the outputs or >>>> some other technique to improve the short and/or long term performance? >>>> >>>> You can monitor one against the other. Ideally you would want three >>>> GPSDO’s and a >>>> monitoring setup. That way you can figure out which of the three has >> gone >>>> bad. >>>> >>>>> >>>>> 2) I’ve become interested in Rubidium Disciplined Oscillators recently >>>> and was now thinking of purchasing one of the PRS-10 that I see on >> Ebay. If >>>> I did that and replaced one of the DOCXOs from one of the Lucent boxes, >>>> what impact would this have on the overall performance both with and >>>> without (when in hold-over)? >>>> >>>> If you go into holdover, you are the exception. Most setups rarely go >> into >>>> holdover. When they >>>> do, it’s because a hurricane just went over the house. Generally that’s >>>> not when the focus is going >>>> to be on timing experiments. >>>> >>>>> Basically, is it worth the money to upgrade one of the boxes to a >>>> Rubidium disciplined oscillator assuming the GPS signal is rarely lost? >>>> >>>> Not worth the money if you are only looking at holdover and have a >> typical >>>> setup. >>>> >>>>> >>>>> 3) Figuring the PRS-10 will cost around $250 when all is said and done, >>>> is there a better option to improve my GPSDO system? >>>> >>>> >>>> Disciplining implies continuously correcting. Rb standards age much less >>>> than a typical >>>> OCXO. Oddly enough their temperature stability may not be as good as a >>>> high end >>>> DOCXO. It is fairly common to try to stabilize the environment your >>>> standards operate in. >>>> To the extent you are successful this reduces the need to deal with >>>> temperature. >>>> >>>> The net effect is that disciplining an Rb at a rate (filter / control >> loop >>>> / manual tweak) of less than >>>> a few days actually makes the Rb worse. Coming up with software to “back >>>> off” on the tuning is >>>> not as simple as it might seem. >>>> >>>> This comes back to the fact that the GPS signal (or any of the sat >>>> signals) are quite noisy. You >>>> need to average them over a *long* time to get good performance. Rb’s >> are >>>> enough better than >>>> a GPSDO OCXO that the time ranges really stretch out …. >>>> >>>>> >>>>> I basically use the GPSDO as a reference for any equipment that takes >> an >>>> input. I have no monetary need for a reference, just an interest. >>>> >>>> For most normal test equipment, a GPSDO output is “plenty good enough”. >> As >>>> a source for fancy >>>> timing experiments … maybe not so much. As a phase noise reference or a >>>> spur free source for >>>> microwave games … also not the best way to go. >>>> >>>> Bob >>>> >>>> >>>>> >>>>> Thanks. >>>>> >>>>> Jerry >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts@febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>> mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>> mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

Turns out is does work - Initially, when I linked them, both boxes had the standby light go out and the unmodified ref-0 (with no GPS receiver) showed Fault and No GPS. So I assumed there was some problem that might be causing them to conflict over the interface, and unplugged it. I've tried it again with more patience and after 10 minutes or so, the modified ref0 goes into standby and the one without a receiver has only the green ON light. I guess that's working correctly :) On Thu, Nov 23, 2017 at 12:23 AM, Jerry Hancock <jerry@hanler.com> wrote: > Adrian, when you stated it didn’t work, what were the results? > > I had mine running in HA mode, if you can call it that, because only one > has a GPS. Actually now that I think about it, the separate but modified > REF0 and modified REF1, assuming separate power and antennas, is probably > closer to HA than the original application. I have both mine running now > with Lady Heather tracking each and I’ve been playing around with > comparisons. Now in my case, if either goes down for any reason the other > can take over. I guess in order to make them truly HA, we would need a > diode or relay switched transfer to the active unit. > > Jerry > > > On Nov 22, 2017, at 4:10 PM, Adrian Godwin <artgodwin@gmail.com> wrote: > > > > Yes, I cross-connected the pins, but I didn't cut any short. > > > > > > > > On Wed, Nov 22, 2017 at 11:36 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > > > >> Hi > >> > >> I have run a number of the REF0 / REF1 combos. They all seem to work > fine. > >> The standard cable has some odd short pins on it. If you are not hot > >> plugging > >> the cable I don’t think they matter at all. If anything, the system is > >> more reliable > >> with a normal length pin on the connector. > >> > >> Bob > >> > >>> On Nov 22, 2017, at 6:08 PM, Adrian Godwin <artgodwin@gmail.com> > wrote: > >>> > >>> I've got several of the Ref 0 boxes but none of the Ref 1. I've added > an > >>> Oncore GPS receiver to one of them as per Peter Garde's notes and it > >> works > >>> well. > >>> > >>> But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 > >>> configuration. Not that I need an HA reference but just for interest. > >> I've > >>> only had a quick look so far and found that connecting the two together > >>> with a 15-pin cable didn't work. > >>> > >>> Has anyone looked into this ? > >>> > >>> > >>> On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > >>> > >>>> Hi > >>>> > >>>> > >>>> > >>>>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: > >>>>> > >>>>> Three questions: > >>>>> > >>>>> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit > with > >>>> both supplying 10Mhz and 1PPS, is there a way to combine the outputs > or > >>>> some other technique to improve the short and/or long term > performance? > >>>> > >>>> You can monitor one against the other. Ideally you would want three > >>>> GPSDO’s and a > >>>> monitoring setup. That way you can figure out which of the three has > >> gone > >>>> bad. > >>>> > >>>>> > >>>>> 2) I’ve become interested in Rubidium Disciplined Oscillators > recently > >>>> and was now thinking of purchasing one of the PRS-10 that I see on > >> Ebay. If > >>>> I did that and replaced one of the DOCXOs from one of the Lucent > boxes, > >>>> what impact would this have on the overall performance both with and > >>>> without (when in hold-over)? > >>>> > >>>> If you go into holdover, you are the exception. Most setups rarely go > >> into > >>>> holdover. When they > >>>> do, it’s because a hurricane just went over the house. Generally > that’s > >>>> not when the focus is going > >>>> to be on timing experiments. > >>>> > >>>>> Basically, is it worth the money to upgrade one of the boxes to a > >>>> Rubidium disciplined oscillator assuming the GPS signal is rarely > lost? > >>>> > >>>> Not worth the money if you are only looking at holdover and have a > >> typical > >>>> setup. > >>>> > >>>>> > >>>>> 3) Figuring the PRS-10 will cost around $250 when all is said and > done, > >>>> is there a better option to improve my GPSDO system? > >>>> > >>>> > >>>> Disciplining implies continuously correcting. Rb standards age much > less > >>>> than a typical > >>>> OCXO. Oddly enough their temperature stability may not be as good as a > >>>> high end > >>>> DOCXO. It is fairly common to try to stabilize the environment your > >>>> standards operate in. > >>>> To the extent you are successful this reduces the need to deal with > >>>> temperature. > >>>> > >>>> The net effect is that disciplining an Rb at a rate (filter / control > >> loop > >>>> / manual tweak) of less than > >>>> a few days actually makes the Rb worse. Coming up with software to > “back > >>>> off” on the tuning is > >>>> not as simple as it might seem. > >>>> > >>>> This comes back to the fact that the GPS signal (or any of the sat > >>>> signals) are quite noisy. You > >>>> need to average them over a *long* time to get good performance. Rb’s > >> are > >>>> enough better than > >>>> a GPSDO OCXO that the time ranges really stretch out …. > >>>> > >>>>> > >>>>> I basically use the GPSDO as a reference for any equipment that takes > >> an > >>>> input. I have no monetary need for a reference, just an interest. > >>>> > >>>> For most normal test equipment, a GPSDO output is “plenty good > enough”. > >> As > >>>> a source for fancy > >>>> timing experiments … maybe not so much. As a phase noise reference or > a > >>>> spur free source for > >>>> microwave games … also not the best way to go. > >>>> > >>>> Bob > >>>> > >>>> > >>>>> > >>>>> Thanks. > >>>>> > >>>>> Jerry > >>>>> > >>>>> _______________________________________________ > >>>>> time-nuts mailing list -- time-nuts@febo.com > >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >>>> mailman/listinfo/time-nuts > >>>>> and follow the instructions there. > >>>> > >>>> _______________________________________________ > >>>> time-nuts mailing list -- time-nuts@febo.com > >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >>>> mailman/listinfo/time-nuts > >>>> and follow the instructions there. > >>>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@febo.com > >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >> mailman/listinfo/time-nuts > >>> and follow the instructions there. > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >> mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

Hi Yes, the “has no GPS” box becomes the active device in a REF0 / REF1 pair. If a survey is involved, it can take a *long* time for things to sort out. Bob > On Nov 23, 2017, at 7:22 AM, Adrian Godwin <artgodwin@gmail.com> wrote: > > Turns out is does work - Initially, when I linked them, both boxes had the > standby light go out and the unmodified ref-0 (with no GPS receiver) showed > Fault and No GPS. > > So I assumed there was some problem that might be causing them to conflict > over the interface, and unplugged it. > > I've tried it again with more patience and after 10 minutes or so, the > modified ref0 goes into standby and the one without a receiver has only the > green ON light. I guess that's working correctly :) > > > > On Thu, Nov 23, 2017 at 12:23 AM, Jerry Hancock <jerry@hanler.com> wrote: > >> Adrian, when you stated it didn’t work, what were the results? >> >> I had mine running in HA mode, if you can call it that, because only one >> has a GPS. Actually now that I think about it, the separate but modified >> REF0 and modified REF1, assuming separate power and antennas, is probably >> closer to HA than the original application. I have both mine running now >> with Lady Heather tracking each and I’ve been playing around with >> comparisons. Now in my case, if either goes down for any reason the other >> can take over. I guess in order to make them truly HA, we would need a >> diode or relay switched transfer to the active unit. >> >> Jerry >> >>> On Nov 22, 2017, at 4:10 PM, Adrian Godwin <artgodwin@gmail.com> wrote: >>> >>> Yes, I cross-connected the pins, but I didn't cut any short. >>> >>> >>> >>> On Wed, Nov 22, 2017 at 11:36 PM, Bob kb8tq <kb8tq@n1k.org> wrote: >>> >>>> Hi >>>> >>>> I have run a number of the REF0 / REF1 combos. They all seem to work >> fine. >>>> The standard cable has some odd short pins on it. If you are not hot >>>> plugging >>>> the cable I don’t think they matter at all. If anything, the system is >>>> more reliable >>>> with a normal length pin on the connector. >>>> >>>> Bob >>>> >>>>> On Nov 22, 2017, at 6:08 PM, Adrian Godwin <artgodwin@gmail.com> >> wrote: >>>>> >>>>> I've got several of the Ref 0 boxes but none of the Ref 1. I've added >> an >>>>> Oncore GPS receiver to one of them as per Peter Garde's notes and it >>>> works >>>>> well. >>>>> >>>>> But I'd like it to run with an unmodified Ref 0 too in the ref0/ref1 >>>>> configuration. Not that I need an HA reference but just for interest. >>>> I've >>>>> only had a quick look so far and found that connecting the two together >>>>> with a 15-pin cable didn't work. >>>>> >>>>> Has anyone looked into this ? >>>>> >>>>> >>>>> On Wed, Nov 22, 2017 at 11:01 PM, Bob kb8tq <kb8tq@n1k.org> wrote: >>>>> >>>>>> Hi >>>>>> >>>>>> >>>>>> >>>>>>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <jerry@hanler.com> wrote: >>>>>>> >>>>>>> Three questions: >>>>>>> >>>>>>> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit >> with >>>>>> both supplying 10Mhz and 1PPS, is there a way to combine the outputs >> or >>>>>> some other technique to improve the short and/or long term >> performance? >>>>>> >>>>>> You can monitor one against the other. Ideally you would want three >>>>>> GPSDO’s and a >>>>>> monitoring setup. That way you can figure out which of the three has >>>> gone >>>>>> bad. >>>>>> >>>>>>> >>>>>>> 2) I’ve become interested in Rubidium Disciplined Oscillators >> recently >>>>>> and was now thinking of purchasing one of the PRS-10 that I see on >>>> Ebay. If >>>>>> I did that and replaced one of the DOCXOs from one of the Lucent >> boxes, >>>>>> what impact would this have on the overall performance both with and >>>>>> without (when in hold-over)? >>>>>> >>>>>> If you go into holdover, you are the exception. Most setups rarely go >>>> into >>>>>> holdover. When they >>>>>> do, it’s because a hurricane just went over the house. Generally >> that’s >>>>>> not when the focus is going >>>>>> to be on timing experiments. >>>>>> >>>>>>> Basically, is it worth the money to upgrade one of the boxes to a >>>>>> Rubidium disciplined oscillator assuming the GPS signal is rarely >> lost? >>>>>> >>>>>> Not worth the money if you are only looking at holdover and have a >>>> typical >>>>>> setup. >>>>>> >>>>>>> >>>>>>> 3) Figuring the PRS-10 will cost around $250 when all is said and >> done, >>>>>> is there a better option to improve my GPSDO system? >>>>>> >>>>>> >>>>>> Disciplining implies continuously correcting. Rb standards age much >> less >>>>>> than a typical >>>>>> OCXO. Oddly enough their temperature stability may not be as good as a >>>>>> high end >>>>>> DOCXO. It is fairly common to try to stabilize the environment your >>>>>> standards operate in. >>>>>> To the extent you are successful this reduces the need to deal with >>>>>> temperature. >>>>>> >>>>>> The net effect is that disciplining an Rb at a rate (filter / control >>>> loop >>>>>> / manual tweak) of less than >>>>>> a few days actually makes the Rb worse. Coming up with software to >> “back >>>>>> off” on the tuning is >>>>>> not as simple as it might seem. >>>>>> >>>>>> This comes back to the fact that the GPS signal (or any of the sat >>>>>> signals) are quite noisy. You >>>>>> need to average them over a *long* time to get good performance. Rb’s >>>> are >>>>>> enough better than >>>>>> a GPSDO OCXO that the time ranges really stretch out …. >>>>>> >>>>>>> >>>>>>> I basically use the GPSDO as a reference for any equipment that takes >>>> an >>>>>> input. I have no monetary need for a reference, just an interest. >>>>>> >>>>>> For most normal test equipment, a GPSDO output is “plenty good >> enough”. >>>> As >>>>>> a source for fancy >>>>>> timing experiments … maybe not so much. As a phase noise reference or >> a >>>>>> spur free source for >>>>>> microwave games … also not the best way to go. >>>>>> >>>>>> Bob >>>>>> >>>>>> >>>>>>> >>>>>>> Thanks. >>>>>>> >>>>>>> Jerry >>>>>>> >>>>>>> _______________________________________________ >>>>>>> time-nuts mailing list -- time-nuts@febo.com >>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>>>> mailman/listinfo/time-nuts >>>>>>> and follow the instructions there. >>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts@febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>>>> mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts@febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>> mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>> mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing 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.