MC3362 tuning range


From: W. Daniel (pandora!daniel@Think.COM)
Date: Tue Jul 05 1994 - 16:48:06 EDT


        Ok, I know I've been posting a lot of mail but I'm curious :) While
looking back in the archives I noted that someone mentioned that one of the
problems with the Gary Breed was the limited tuning range, 48 kHz to be precise
and I have personally confirmed this with the design given in the ARRL Handbook
for 20M. While pondering over this and going through the data sheet for the
MC3362 I noticed that the internal varicap diode is actually a back-to-back
varicap placed across pins 21-22. I thus wondered if it was possible to extend
the range of the Breed VFO by placing another similar back-to-back varicap
across pins 21-22 (the LC tank) and biased it with the voltage at pin 23. Will
there be any problems with this scheme? If not, why hasn't anyone done it yet?
Tks. I most likely will base my next RX on the MC3362 so I really want to know.


| Daniel Wee  |             | ** Man needs more
| UUCP1.12b   | |  than a new start, he
| SNEWS 1.91  |!pandora!daniel             |  needs a new heart! **

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