[Lowfer] Frequency correction

Wed, 6 Nov 2002 16:23:50 -0600

OK, that would be great. I didn't realize that it was such a small change in
capacitance. I thought about the drift with the tuning diode and pot later
on today. Thanks for getting the finals out. Denise shipped the caps
yesterday via the post office.
73's,
Mike>WE0H
http://www.we0h.us/lf.html

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Bill Ashlock
Sent: Wednesday, November 06, 2002 12:34 AM
To: lowfer
Subject: Re: [Lowfer] Frequency correction

Mike,

>Now watch the oscillator will get weird because the crystal's load changed.

Would it get weird from changing the series capacity from about 10pf to
9.999pf? We are talking about less than a 2 ppm change.

>How about a multi-turn pot and a tuning diode??? That should be able to QSY
>all over the place (VXO).

Oh yah that's all I need - a basically temperature sensitive component to
mess up a < 2 ppm per year drift? Already have a npo trimmer that gives me
plenty of tuning range. Actually I have tuning cap in the circuit to insert
the slant modulation but it has only a 1 ppm effect because it is in series
with a 1pf capacitor - so the tuning cap tempco has a minimal effect on
overall freq stability. I'll send you the circuit.

BTW I sent the transistors from work today (Tues).

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