Bliley 100 kc BG9D crystal follow-up.
 

I cobbled up a two transistor oscillator, essentially copied from an
Atlas 210 Transciever schematic, to run the BG9D I got on Ebay while
back. The circuit is he

http://novatech-instr.com/Fun/Crystals/bliley_q.jpg

I took an old octal based capacitor, emptied the insides and wound 106
turns (53 bifilar) of #27 wire on the aluminum case. This is the
heater. About 1 amp heated nicely to 70C. I used some hot-water pipe
insulator to cover it. An LM61 is used as a temp sensor. (epoxied to
the can) (I'll put up the temp controller schematic when I remember)

It is hard to set much closer than about +/-1ppm (needs a better
multiturn capacitor), but it is stable (short term) to better than
+/-.01ppm. That's pretty nice, but other than the fun of building it,
the performance is pretty useless. Roughly the equivalent of building a
crystal radio set.

I am going to replace the transistor with a 12AT7, just for show, and
call this little experiment done.

Steve.
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA