You do know that neither a 117A or a 207 will work when WWVB changes to BPSK fairy soon?
-John =============== > Thanks Charles: > I will consider your ideas as they seem to be excellent! > > I wonder if I could just make the whole unit run off of +24VDC or +12 > VDC. > I need to look at the schematics and see what would be the best way to > proceed. > > I currently do not have an antenna for WWVB and need to get up and > running before I do anything with it. > > If successful, would anyone want information on my conversion? I also > have a fluke 207 that needs to be recapped. > Thanks, > Ron > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Charles P. Steinmetz > Sent: Wednesday, July 04, 2012 11:10 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] HP 117/10509a > > Don wrote: > >>the fet breakdown voltage has of course got to be high enough. > > If the nuvistor is used as a common-cathode or common-grid amplifier, > you can cascode the fet with a bipolar to extend its drain voltage > range. You will need to come up with an appropriate bias source for > the bipolar. Generally, you would want at least 10-15 volts across > the FET channel. > > Choose an appropriate JFET (transconductance, drain current, and > gate-drain voltage similar to the nuvistor at the nuvistor's > operating point). You can add degeneration (source resistance) to > lower the FET's transconductance if it is higher than the nuvistor's. > > Best regards, > > Charles > > > > > > _______________________________________________ > 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. > > _______________________________________________ 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.
