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Old March 20th 04, 11:02 PM
Paul Burridge
 
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On Sat, 20 Mar 2004 10:13:22 -0500, "Tam/WB2TT"
wrote:

Paul,
If you are trying to keep things small, have you considered one of the high
speed versions of the 4046 PLL/OSC? Some manufacturers spec these up to 20
MHz. No coils. If you go with the LC, and you have any fixed capacitors in
parallel with the inductor, use decent capacitors, like mica or RF approved
ceramic. I have seen cheap ceramic caps meant for bypassing just not work in
applications like yours.


That's a point well worth remembering, Tam: it's not just coils that
exhibit a Q-factor and just as much harm can be caused by using lossy
capactors in tuing applications, too.
The PLL suggestion is a good one, but I'm trying to keep things simple
for this fairly straightforward project. It's nice to be able to build
everything just from what's in the junkbox.
--

The BBC: Licensed at public expense to spread lies.