You could try tuning in a broadcast station. They are generally very close
in freq. I use a GPS based 10 mhz reference. Calibration of deviation is
more difficult but setting up known deviations with a good fm signal
generator and a spectrum analyzer using bessel zero or carrier null method
will produce very accurate deviations without the need foe another deviation
meter to compare with

Russ - WA4POD

Richard W. Solomon, W1KSZ wrote in message
...
How do you go about calibrating the frequency accuracy of your Service
Monitor ? I know I could go to a local Cal Lab and pay the price, but
I like the idea of doing it myself. I do not service and commercial or
Public Service radios, only HAM so the critical nature of accuracy is
not that severe.
One idea a friend had was to set the Monitor to receive and pick a
signal off the air. He suggested the Mass. State Police as they are
locked to GPS (according to him) or one of several paging systems that
he said were also locked to GPS.
That seems to be a good idea, especially since you are looking at
freqs in the 800-900 MHz region. Of course, one needs to know the
absolute frequency, just being locked to GPS is meaningless unless
they really are "on freq".
Curious what other folks do.

Thanks, Dick, W1KSZ