"James Meyer" wrote in message
...
On Wed, 25 Feb 2004 19:47:49 GMT, "Robert C Monsen"

posted this:


"Paul Burridge" wrote in message

Interesting. This is the type I've decided to build as the basis for
my next sweep generator attempt, since it's claimed the config is more
amenable to being pulled than most others (although I won't be
attempting to pull it anything like as much as my first abortive
attempt using a Cmos-based inverter). Do you find it's a reliable and
stable design, Jim? I assume if it wasn't you wouldn't still be using
it!

Why not use a VCO built from an LC oscillator? Its really easy to build
one
with a single transistor that sweeps your band.


Major problem with that idea is the fact that Paul has no way to
calibrate or adjust the VCO. That's why he wants to start with a crystal
oscillator. If it works, he won't have to calibrate it.


I thought he wanted a VCO so he could sweep the range from 40.5MHz to 41MHz.
Using a frequency counter, it would be trivial to tune this circuit to start
wherever he wanted. Frequency counters are cheap on ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll...tegory=48 701

Using a crystal oscillator would obviously be better, but it sounds like he
is having trouble getting the range he needs out of it.

Regards,
Bob Monsen

Jim