Hi all, Brooke Clark wrote:
> In the HP 5100 Frequency Synthesizer they use a heater on the SRD in order to > increase it's > lifetime so that the 3 MHz drive will generate the needed harmonics. > http://www.prc68.com/I/HP5100.shtml These > assemblies are no longer available and getting an SRD with a lifetime long > enough to work with a 3 MHz input is a common > as chicken teeth. A solution is to get a large stud mounted Varactor and > these do have long lifetimes. I was so pleased to see this. It mirrored my experience exactly. A few years ago I restored a 5100A and its 5110A exciter. The SRD heater in the 5110A had developed a failed thermostat and was a charred blob. I made up a test jig and tested lots and lots of different diodes and as it turned out, the best candidate was a stud mounted varactor out of a junked transmitter from the old VHF cellphone system. It's worked like a charm ever since. This post (and webpage) has explained it beautifully. Morris _______________________________________________ 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.
