[Test-Equipment] esidual FM measurements

[Carl Walker]

>OK, I didn't feel like going to bed just yet, so: a comparison at
>http://www.speakeasy.net/~jmiles1/gens.gif�shows all three generators
>running at 100 MHz. 

You seem to have even more trouble sleeping than I do ;-)

Thanks for running the comparison, John. You've helped to to verify what I 
feared most - this old 8656A just isn't suitable for my applications.

>Needless to say, a +/- 30 Hz peak variation in frequency is readily audible
>in a CW receiver, especially at low beat frequencies.

Without question - and one of my routine tasks when playing around with a 
CW/SSB receiver design is to listen for signs of instability or microphonics. 
While this generator may be suitable for FM or AM receiver work, it is just 
plain useless for more demanding applications. Into the scrap pile it goes.

>The biggest complaints I have about the 8656A isn't its phase noise, but its
>fan noise! �I keep mine on a separate power strip, so I can shut the whole
>thing down, including its always-on fan, when I'm not using it.

Very true - I've been forced to do the same thing - and it really wasn't a 
big deal, since I was running it off an external standard instead of the 
internal OCXO. Normally, I'd be willing to put up with that limitation, but 
the residual FM issue makes this particular flavor of generator simply not 
worthy of the bench space it is occupying (at least in my particular case).

Time to go shopping again...

Thanks for taking the data.

73,

-Carl, WA1RAJ