On Sat, 13 Mar 2004 17:45:23 +0000 (UTC), "Reg Edwards"
wrote:

Here's the solution. Build a 17.2 one-transistor LC oscillator. It will
easily lock to an injection of the 5th harmonic of 3.44 Mhz at any output
level you like.

Whatever you do don't go for phase locked loops.

Junk your Spice. It tells you nothing you didn't already ought to know. If
you don't know it then you shouldn't be doing the job anyway.

You must have plenty of room on the PCB. But why don't you invest in a 17.2
MHz quartz crystal. They're cheap enough. You've already spent more time
and trouble on research and investigation. Cut your losses.

Hi Reg,

I'm not into cutting my losses and taking the easy way out; I wouldn't
*learn* anything by doing so. This circuit *ought* to work and I hope
to find out why it doesn't and remedy the situation.
I can't build a 17.2Mhz osc. I need to start much lower to multiply up
the 'pullability' of the fundamental to the best part of half a Meg.
Try doing that with a quartz xtal at 17Mhz! Sorry, I mean no offence I
know you're unaware of the background to this project.
BTW, I've built the filter your s/ware designed and it works pretty
much as advertised - bang on 17.2Mhz pass[1] and the third harmonic of
the fundamental at just over 10Mhz is *well* down by a factor of 80X
(sorry, can't be arsed to work out the dB equivalent). The coils I
used to build it were designed with one of your other programs, BTW!
Many thanks indeed. I urge anyone else reading this in r.r.a.hb to
grab Reg's programs whilst they can; they're *extremely* useful and
Reg deserves a vote of thanks from us all for taking the time and
trouble to write them.

[1] Significant spurious pass response at 13.2Mhz for some reason
(probably my use of inappropriate capacitors for the sake of
expediency - Spice didn't predict it) fortunately it just misses the
fourth harmonic!
--

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