Hi If you *need* portability, an internal oscillator is a good thing. If you want to fire something up fast, an OCXO is not a good choice. That’s a bit of a problem. A few real choices: 1) Get something like the LTE that locks up to GPS and runs right away. When portable, bring along a small GPS antenna. 2) Run a TCXO in the counter while portable and an external reference on the bench. 3) Power up the counter with internal OCXO the night before any “portable” measurements. There really aren’t a lot of other options unless you head off into the portable atomic clocks. Bob > On Nov 30, 2014, at 11:08 AM, Götz Romahn <goetz@g-romahn.de> wrote: > > Adrian, > if you do not insist on a hp10811A, have a look at Gerrys site > http://gerrysweeney.com/update-diy-hpagilent-53131a-010-high-stability-timebase-option-pcbs-available/ > You can buy an assembled option 10 compatible OCXO modul for less than 100 GBP. > I built DIY one with a PCB from Gerry using my Morion MV89 OCXO and it is working fine. Fully compatible with hp53131 calibration procedure. > Götz > > > > Am 29.11.2014 22:19, : >> Is the upgrade similarly easy on a 53131A ? >> >> I realise that it needs to have an additional controller pcb but I >> have one of these counters fitted with option 001. The pcb holding the >> oscillator has an edge connector that looks suitable for a 10811A, and >> I have one to hand as well as a couple of compatible oscillators. >> >> I think I would need to remove the existing TCXO module - I haven't >> investigated too carefully yet but I think it's soldered in, and >> obstructs the mounting of the 10811A. >> >> On Sat, Nov 29, 2014 at 5:20 PM, Dr. David Kirkby (Kirkby Microwave >> Ltd) <drkirkby@kirkbymicrowave.co.uk> wrote: >>> On 27 November 2014 at 22:38, Dr. David Kirkby (Kirkby Microwave Ltd) >>> <drkirkby@kirkbymicrowave.co.uk> wrote: >>>> The HP 5342A has an optional oven oscillator. I just bought one of >>>> those counters, but mine has a TCXO and is about 50 kHz off at 10 GHz. >>>> I'm sure I can trim it closer than that, but if possible I'd like to >>>> stick an oven oscillator in it. Does anyone know what is involved? I >>>> have at least one 10811A oscillator here that I could stick inside, >>>> but does it need any more, or just the oscillator? >>>> >>>> Someone said the oscillator should be an 10544-60011, but a 10811A is >>>> backwards compatible. >>>> >>>> Dave >>> >>> It was very easy to fit the 10811A oven (HP 10811-60111) and get the >>> oven working, although the oven is not powered when the counter is not >>> switched on, even if there is power at the AC mains input. I can live >>> with that. In fact, I prefer it to be honest. >>> >>> The procedure was >>> >>> 1) Remove top and bottom covers, which means the two front feet, plus >>> 4 rear feet/protectors need to be removed. >>> >>> 2) Undo one screw at the top that held a board with a TCXO on it. The >>> board plugs into a 15-pin edge connector. >>> >>> 3) Pull out the board (HP P/N 05341-60047) with the TCXO. The TCXO on >>> the board is a marked DALE, TCXO-22-1, 0960-0394, 10.0MHz, SET 1.0Hz. >>> (normally I would put a space between a number and the units, but I've >>> written what is actually on the TCXO). >>> >>> 4) Attempt to insert the 10811A oscillator. This failed, as there were >>> some wires around the optional board for GPIB which were restricting >>> the space too much. So I had to cut a wire tie, and move the wires out >>> the way. >>> >>> 5) Fitted 10811A at the top. >>> >>> 6) Invert the counter, and screw in the two screws which secure the >>> 10811A to the chassis. For this I needed to temporarily move a ribbon >>> cable, as the screw was below it. >>> >>> 7) Powered it up, and it worked. It shows "OVN" in the right of the >>> LED display. Once that went out, it still took a minute or two for the >>> readings to become pretty stable, although no doubt it will take >>> months to become as good as it will get. >>> >>> I've not adjusted it yet, as I don't have any accurate frequency >>> reference. But whilst the actual frequency indicated on the counter is >>> different from what my signal generators are supposed to be producing, >>> the last few digits (100, 10 and 1 Hz), are not all jumping around >>> when seeing 10 GHz. >>> >>> The frequency indicated on the counter when connected to two different >>> signal generators, which both have ovens of unknown type, are: >>> >>> 1) HP 83623A 20 GHz sweeper set to 10.0 GHz, fed into high frequency >>> input of the frequency counter. >>> HP 5342A counter indicates 10,000,000,690 Hz (relative difference = +6.9 10^-8) >>> >>> 2) HP 8656A set to 100 MHz, >>> HP 5342A counter indicates 99,999,987 Hz (relative difference = -1.3 x 10^-7) >>> >>> With the old TCXO in the frequency counter, the indicated frequency of >>> the 10 GHz signal was about 48 kHz off, but it moved around a KHz or >>> so. In contrast, now the oven is installed, the reading is a *lot* >>> more stable, with it shifted about 15 Hz. >>> >>> I don't currently know the absolute accurate any of the references in >>> the test equipment are, but certainly the readings are a lot more >>> stable after fitting the oven. >>> >>> I will need to get a GPSDO before adjusting any, but if nothing else, >>> the short term stability of the oven is clearly superior to the TCXO. >>> Long term should be too, but I can't determine that from what I have. >>> >>> Dave >>> _______________________________________________ >>> 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.

I've seen Gerry's board and might well fit one to another counter. However, this already has a suitable board - in fact, it appears it is an oven, not a tcxo. Presumably just not as good an oven. The point is, it looks ready to receive a 10811A. In fact, consulting the assembly-level service guide does seem to confirm that it uses an Isotech oven for medium stability or one of two 10811 variants for high and ultrahigh stability. Since the 10811A I have is an older model, neither 10811-60160 or 10811-60260, is it likely I'll get any improvment over the Isotech 1813-0931 ? Photos of the board : https://www.dropbox.com/s/w4nngyz1qp70skv/P1280343.JPG?dl=0 https://www.dropbox.com/s/ifjcx6xzz90vlja/P1280344.JPG?dl=0 On Sun, Nov 30, 2014 at 4:38 PM, Bob Camp <kb8tq@n1k.org> wrote: > Hi > > If you *need* portability, an internal oscillator is a good thing. If you want to fire something up fast, an OCXO is not a good choice. That's a bit of a problem. > > A few real choices: > > 1) Get something like the LTE that locks up to GPS and runs right away. When portable, bring along a small GPS antenna. > > 2) Run a TCXO in the counter while portable and an external reference on the bench. > > 3) Power up the counter with internal OCXO the night before any "portable" measurements. > > There really aren't a lot of other options unless you head off into the portable atomic clocks. > > Bob > >> On Nov 30, 2014, at 11:08 AM, Götz Romahn <goetz@g-romahn.de> wrote: >> >> Adrian, >> if you do not insist on a hp10811A, have a look at Gerrys site >> http://gerrysweeney.com/update-diy-hpagilent-53131a-010-high-stability-timebase-option-pcbs-available/ >> You can buy an assembled option 10 compatible OCXO modul for less than 100 GBP. >> I built DIY one with a PCB from Gerry using my Morion MV89 OCXO and it is working fine. Fully compatible with hp53131 calibration procedure. >> Götz >> >> >> >> Am 29.11.2014 22:19, : >>> Is the upgrade similarly easy on a 53131A ? >>> >>> I realise that it needs to have an additional controller pcb but I >>> have one of these counters fitted with option 001. The pcb holding the >>> oscillator has an edge connector that looks suitable for a 10811A, and >>> I have one to hand as well as a couple of compatible oscillators. >>> >>> I think I would need to remove the existing TCXO module - I haven't >>> investigated too carefully yet but I think it's soldered in, and >>> obstructs the mounting of the 10811A. >>> >>> On Sat, Nov 29, 2014 at 5:20 PM, Dr. David Kirkby (Kirkby Microwave >>> Ltd) <drkirkby@kirkbymicrowave.co.uk> wrote: >>>> On 27 November 2014 at 22:38, Dr. David Kirkby (Kirkby Microwave Ltd) >>>> <drkirkby@kirkbymicrowave.co.uk> wrote: >>>>> The HP 5342A has an optional oven oscillator. I just bought one of >>>>> those counters, but mine has a TCXO and is about 50 kHz off at 10 GHz. >>>>> I'm sure I can trim it closer than that, but if possible I'd like to >>>>> stick an oven oscillator in it. Does anyone know what is involved? I >>>>> have at least one 10811A oscillator here that I could stick inside, >>>>> but does it need any more, or just the oscillator? >>>>> >>>>> Someone said the oscillator should be an 10544-60011, but a 10811A is >>>>> backwards compatible. >>>>> >>>>> Dave >>>> >>>> It was very easy to fit the 10811A oven (HP 10811-60111) and get the >>>> oven working, although the oven is not powered when the counter is not >>>> switched on, even if there is power at the AC mains input. I can live >>>> with that. In fact, I prefer it to be honest. >>>> >>>> The procedure was >>>> >>>> 1) Remove top and bottom covers, which means the two front feet, plus >>>> 4 rear feet/protectors need to be removed. >>>> >>>> 2) Undo one screw at the top that held a board with a TCXO on it. The >>>> board plugs into a 15-pin edge connector. >>>> >>>> 3) Pull out the board (HP P/N 05341-60047) with the TCXO. The TCXO on >>>> the board is a marked DALE, TCXO-22-1, 0960-0394, 10.0MHz, SET 1.0Hz. >>>> (normally I would put a space between a number and the units, but I've >>>> written what is actually on the TCXO). >>>> >>>> 4) Attempt to insert the 10811A oscillator. This failed, as there were >>>> some wires around the optional board for GPIB which were restricting >>>> the space too much. So I had to cut a wire tie, and move the wires out >>>> the way. >>>> >>>> 5) Fitted 10811A at the top. >>>> >>>> 6) Invert the counter, and screw in the two screws which secure the >>>> 10811A to the chassis. For this I needed to temporarily move a ribbon >>>> cable, as the screw was below it. >>>> >>>> 7) Powered it up, and it worked. It shows "OVN" in the right of the >>>> LED display. Once that went out, it still took a minute or two for the >>>> readings to become pretty stable, although no doubt it will take >>>> months to become as good as it will get. >>>> >>>> I've not adjusted it yet, as I don't have any accurate frequency >>>> reference. But whilst the actual frequency indicated on the counter is >>>> different from what my signal generators are supposed to be producing, >>>> the last few digits (100, 10 and 1 Hz), are not all jumping around >>>> when seeing 10 GHz. >>>> >>>> The frequency indicated on the counter when connected to two different >>>> signal generators, which both have ovens of unknown type, are: >>>> >>>> 1) HP 83623A 20 GHz sweeper set to 10.0 GHz, fed into high frequency >>>> input of the frequency counter. >>>> HP 5342A counter indicates 10,000,000,690 Hz (relative difference = +6.9 10^-8) >>>> >>>> 2) HP 8656A set to 100 MHz, >>>> HP 5342A counter indicates 99,999,987 Hz (relative difference = -1.3 x 10^-7) >>>> >>>> With the old TCXO in the frequency counter, the indicated frequency of >>>> the 10 GHz signal was about 48 kHz off, but it moved around a KHz or >>>> so. In contrast, now the oven is installed, the reading is a *lot* >>>> more stable, with it shifted about 15 Hz. >>>> >>>> I don't currently know the absolute accurate any of the references in >>>> the test equipment are, but certainly the readings are a lot more >>>> stable after fitting the oven. >>>> >>>> I will need to get a GPSDO before adjusting any, but if nothing else, >>>> the short term stability of the oven is clearly superior to the TCXO. >>>> Long term should be too, but I can't determine that from what I have. >>>> >>>> Dave >>>> _______________________________________________ >>>> 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.