Thanks Bob, I got some offline help from someone and I redid my setup and I am now getting decent data. It looks like it was finger problems. It has only been warming up for a day but it is now looking decent. Once I get a longer plot I will post all the things I did wrong in my setup. It was the first time I was measuring a 5Mhz source against the 10 MHz on GPSDO. And I learned something important.
I got the HP105B for $300 so I think I got a decent deal. No battery which is probably a good thing. A couple of resistors and a couple of electrolytics. The next step is to bring out the 10 Mhz to the back. Open to suggestions on how best to do that. I do recall recently someone posted a buffer solution using a LH0033CG. I did get some of those from Fleabay. I do recall there were some comments that those parts were not a good choice. Thanks everyone I am not off to the races and look at it closer. Dave VE7HR On Sun, Dec 13, 2020 at 5:58 PM Bob kb8tq <[email protected]> wrote: > Hi > > The “better” 10811’s were sorted out from the “general population”. There > is a > lot of anecdotal evidence that (at least for phase noise) far more hit the > better > categories than got labeled as such. > > If indeed your device seems to have trouble, the OCXO is a likely > candidate. > The power supply can be checked with a DVM (and maybe a scope). The output > amps can be checked by tapping directly in to the oscillator output. EFC > issues > can be tossed out by grounding the EFC. > > Given the eBay price ratio between the 105 and 10811 prices, the roundoff > error > in the 105 price pretty well covers a 10811 or three …. > > Bob > > > > On Dec 13, 2020, at 7:38 PM, Dave Miller <[email protected]> wrote: > > > > Thanks Bob, > > No rust just a couple of electrolytics leaked taking out a couple of > nearby > > parts. > > Everything else looks very nice. > > > > I might be able to find another 10811 to try. I thought there were > > different versions > > The specified one was supposed to be special low phase noise. > > But I know nothing about this as I am a rookie. > > > > This is the setup as I forgot to post it in original post > > > > 5370B > > TI > > 1PPS from HP GPSDO to Arm > > External arm > > 10 MHZ form HP GPSDO to start > > Stop is 5 MHz output from HP105B 5MHz > > The ADEV is terrible > > There is a sawtooth on the Original Phase difference linear residual that > > seems very repeatable and may explain the apparent jitter of the output. > > > > Dave > > > > > > > > On Sun, Dec 13, 2020 at 4:31 PM Bob kb8tq <[email protected]> wrote: > > > >> Hi > >> > >> If the inside of the 105 went under water long enough to rust out a lot > >> of parts on the boards, it’s a good bet that the 10811 in the unit got > >> hit pretty hard as well. > >> > >> Simple answer: Spend $40 on an eBay replacement for the 10811. > >> It should just plug in …. > >> > >> Bob > >> > >>> On Dec 13, 2020, at 5:15 PM, Dave Miller <[email protected]> wrote: > >>> > >>> I am in the middle of resurrecting a HP105B, It is one of the later > >> models > >>> with an 10811 in. > >>> > >>> I have fixed the obvious issues like the electrolytics that were > missing > >>> and other parts that had leads evaporated due to corrosion. > >>> > >>> The basics seem to work, A not bad looking sine wave etc. > >>> But the ADEV numbers are terrible. > >>> I am going back to make sure it's not a measurement setup issue. That > is > >>> good. Just tested another OCXO and the test setup is good. > >>> Attached in a link to a .tim file > >>> https://www.dropbox.com/s/zebwiqy913v7k0k/HP105B%20test.tim?dl=0 > >>> I am hoping one of the more knowledgeable folks might suggest where to > >>> start looking. > >>> I have checked all the other electrolytics and the ESR and capacitance > >>> looks good. I think the power supply seemed clean. > >>> > >>> I have taken out the easy to get boards and cleaned card edges etc but > >> this > >>> persists. > >>> > >>> The saw tooth on the original phase is yelling something at me but I > >>> don't have a clue. > >>> > >>> Thanks > >>> Dave > >>> > >>> -- > >>> 72 de Dave > >>> VE7HR > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > > > > > -- > > 72 de Dave > > VE7HR > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > -- 72 de Dave VE7HR _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
