On 29 Jan 2015 08:39:13 GMT, Rob wrote:

nothermark wrote:
On Wed, 28 Jan 2015 18:17:08 -0500, "Ralph Mowery"
wrote:


"nothermark" wrote in message
...
I need a simple poor ham's deviation meter. That got me looking at
the IC-7100 receiver sitting in my shack. I could get to the
discriminators but it would be a bit messy. OTOH it has a 10.7 MHz IF
output I could add an amplifier and detector to and feed that to my
O'scope to do what I want for long enough to sort out some problems.
That got me looking for a simple detector circuit. No joy so far. I
would really appreciate any pointers to either a circuit I could
breadboard or a canned solution. I was thinking I'd go commercial and
add some gain for a better look the narrow bandwidths used in
communications gear but anything that will work with normal HT's will
solve my problem. Thanks for any help!

If just for a short time, just hook the scope to any audio point before the
voulme control. There may be a monitor output already that you can use.
You can then calibrate the devisions on the scope against a known source.
While not real good and varies with the frequency of the audio source, just
hook the scope across the speaker or plug in an external speaker. Youjust
have to set the volume at one point and not change it from the calibration
point you use.

If you can find an old scanner that has a true descriminator output instead
of the phase detector types, then it is easy. Hook a DC scope to that point
and fine a transmitter that has 1 khz steps . Go up and down one 1 khz at a
time and see where the trace goes. At each point will be the 1 khz steps.

Hmmm, had not thought about that as I am also looking for a deal on a
signal generator. Come to think of it a 1 KHz shift between the
receiver and a transmitter will look like 1 Khz of deviation....

Of course in these days you can use an RTL2830 DVB-T stick as a measurement
device (with some software like SDR#)

For $10 you will have a spectrum analyzer, measurement receiver and
deviation meter, without using your receiver or scope.

I did not know that. Do you have a link to where to start?