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Old November 2nd 06, 03:51 AM posted to rec.radio.amateur.homebrew
AndyS AndyS is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 119
Default More on matching -- Xtal filters this time


Joel Kolstad wrote:
Thanks for the help, Andy... I muddled through it (it's a little odd the first
time you've normalized your Smith chart to 1800 ohms and the termination is 50
ohms!) and the filters do work as their data sheets say.

I did find that xtal filters can easily drive a network analyzer nuts... even
for looking at a single frequency, I had to significantly increase the
sampling time well above the default to get a stable display. I'm thinking
this is due to the absurdly high Q of the crystals causing a very long
transient response, thereby necessitating a long sampling time to finally
measure the steady state response.

---Joel


Andy writes:

I liked using the old Telonic sweep generators, with the two big
dials, and a diode detector/scope to scan the filter bandpass.
I don't have one, or access to one anymore, and have to do
it by hand.....
But, what the hell. Retirement gives me a lot of time to
twiddle knobs...

Andy W4OAH