Bob, Great info. I'll check that too on the next trip.
For right now, we are using a stock GE pre with about 10 db gain and no attenuators. There has been enough great feedback from the group that will give me several hours of testing on the next trip. There are all kinds of things to try. I was hoping for a quick - just do this - answer, but it looks like it doesn't work that way. With all this new info, we'll be ready to optimize the receive system at any of our sites. Thanks guys, Dwayne Kincaid > At 3/22/2007 09:34 AM, you wrote: > >Bob, > > > >How would we know if the preamp is nonlinear or not? > > Only way to know for sure is to connect a spectrum analyzer to the output > of the preamp & look for anything greater than, say -15 dBm. The > advertised 1 dB gain compression point (P1dB) for these preamps is +12 dBm, > though other brands I've measured clocked in a bit lower than this (+7 dBm) > so unless you measure it I'd assume the worst. > > If it's oscillating you'll see a very strong continuous signal, possibly > near the 100 mW level so start the spectrum analyzer on a high reference > level with some internal attenuation. > > Bob NO6B >
