Scott wrote:
Hello All----
Here is a "crystal" question for the
group. Do crystals vary in the amount of random phase noise produced in
or by a typical crystal oscillator / FM modulator circuit as used in a
typical repeater transmitter? Now, more to the issue. I have a series
of repeaters that have more transmitted background audio hiss than the
average of other repeaters on the band. I have, in testing, dissabled
all of the audio modulating circuitry up to the varicap diode without
any change in transmitted noise . This leaves only the crystal and it's
oscillator circuit as the culprit noise source-------hence my question.
Do crystals vary in produced FM (phase) noise. If the answer is yes,
Which crystal manufactures make quiet crystals and just how does one
insure that he gets this need across to a crystal supplier?
I don't believe the crystal or oscillator is to blame, but I could be
wrong. What make and model of equipment are you dealing with? Is it
true FM or phase modulated?
Kevin Custer
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