Re: [amsat-bb] Re: [sarex] What am I doing wrong...?]

[Joe Leikhim <jleikhim@xxxxxxxxxxxx>]

Try this procedure;
Connect your scope (DC coupled) directly to an FM receiver's
discriminator. With a signal generator set "on-freq", adjust the scope
to be "zeroed", then offset the generator first plus 5 KHz and then
minus 5 KHz in frequency and adjust the scope for say, 1 KHz (or better
yet 1/2 KHz) per division resolution. Once that reference is properly
set, adjust your transmitter limiter circuit so that deviation does not
exceed +/- 5 KHz, then adjust your TNC so that it is modulated
comfortably just below limiting. (more is not better here!). (For the
purists: Obviously if narrowband channels are used, the deviation
limiting needs to be set accordingly.)

Guido wrote:
>I full agree with the need to set a correct TX deviation, but what is
the
>way (for an average ham...) to measure it ???
>I have a Tek 100 MHz scope, HP old (and nice:-) HF-VHF-SHF signal
generators
>and frequency meter, and the usual shack stuff.
>Someone can explain a technically-correct procedure ?
                                                 thank in adwance, 73 de

>Guido,
I>4XQG




--
Joe Leikhim K4SAT
Jleikhim@nettally.com

http://www.ibiblio.org/jimmy/mcguinn/9000e.ram

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"The large print giveth
 and the small print taketh away..." Tom Waits.


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