Hi The normal 10811 package has several openings in it. Light *might* get in there. A "micro volts" level of noise can mess up your phase noise if it's AC noise at a low frequency.
Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Adrian Sent: Friday, October 19, 2012 4:10 PM To: rich...@karlquist.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 10811 Tuning Diode I didn't notice any damage, nor was there a visibly bad solder joint. However, I couldn't reproduce the excess noise with a quick bench test at 30V / 100k neither. DC-wise there are a few microvolts only. Same with the SMD diode. Exept, when the original glass diode is exposed to light. With a LED Maglite, I got up to 50 mV (across 100 kOhm) out of it! But there is no light shining inside of a 10811, is there? I had first suspected a 0.1 ceramic cap, but that didn't cure the phase noise desease. The diode in the original circuit appeared to be heat sensitive, and the excess phase noise has gone away since I replaced the diode. The noise was clearly there, and it was also there using a test adapter and two lab power supplies. Adrian Rick Karlquist schrieb: > I wonder if the glass case got a crack in it or if the kovar seal > was failing. Maybe a failed solder joint (which gets fixed when you > install the new diode). I've never heard of a noisy varactor before either. > > Rick > > > _______________________________________________ > 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.