I'm sure there's various ways of doing it, a phase locked oscillator perhaps, dividing 10MHz by 50, or perhaps my preferred lazy method of dividing 800KHz by 4:-) It really doesn't really matter all that much, the initial comment was just that it might be better to provide a 200KHz signal from an alternative source rather than attempt to modify the 5090 to accept 198KHz and the implementation itself should be quite straightforward. Nigel, GM8PZR In a message dated 19/06/2017 14:46:59 GMT Summer Time, cjaysharp@gmail.com writes: If it's just locking to the carrier I wonder if it'd be possible to use a suitably modified PICDiv clocked from a 'standard' 10MHz GPS locked device like the Lucent? On 19 June 2017 at 14:19, GandalfG8--- via time-nuts <time-nuts@febo.com> wrote: I suppose a converter from 198KHz could be an option but I know of at least one other experimenter who's run into problems with the Teleswitch modulation on the Droitwich signal when trying something similar with a 5090A. Although, from one point of view, running it from the present 198KHz signal might be considered the ultimate goal it's the operation of the hardware itself that's of more interest to me in this instance, so I'm quite happy just to feed it with an accurate 200KHz signal from whatever other sources are available. Nigel, GM8PZR How about building a frequency converter to produce 200KHz; mixing the incoming RF (198KHz) with 2KHz derived from the output of the unit, On 18/06/2017 21:17, GandalfG8--- via time-nuts wrote: > Hi Pete That's quite good timing, if you'll pardon the expression:-), as I uploaded a pdf version of the 5090A manual to mediafire a couple of months ago.... _http://www.mediafire.com/file/http://www.mediafire.com/filehttp://www.medi_ (http://www.mediafire.com/file/u0bf1eips89uo3h/HP_5090A_Ops_and_Service.pdf) I know a few others have considered converting the 5090A to 198KHz but it's not straightforward and I believe the general consensus has been that it's not really worth the effort. I have a 5090B which I'm hoping to get up and running when it finally reaches the top of the to do list and my view is that it would be much better to leave the original electronics undisturbed and to drive it with a 200 KHz signal divided down from a from a GPSDO or a rubidium module, although having one of the latter already running at 800KHz does leave me a bit biased:-) Regards Nigel, GM8PZR _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to _https://www.febo.com/cgi-bin/https://www.febo.com/cgi-b_ (https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts) and follow the instructions there. -- Clint. No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.