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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> >> 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 <[email protected]> wrote: >>>>> >>>>>> Hi >>>>>> >>>>>> >>>>>> >>>>>>> On Nov 22, 2017, at 5:16 PM, Jerry Hancock <[email protected]> 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 -- [email protected] >>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>>>> mailman/listinfo/time-nuts >>>>>>> and follow the instructions there. >>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- [email protected] >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>>>> mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- [email protected] >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>> mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- [email protected] >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>> mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
