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) <[email protected]> wrote: > On 27 November 2014 at 22:38, Dr. David Kirkby (Kirkby Microwave Ltd) > <[email protected]> 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 -- [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.
