At 3/20/2008 16:45, you wrote: >Dave VanHorn wrote: > > > Improving the receiver means that I end up just needing more > > attenuation after the preamp, and it looks like that is telling me > > that what I really need is a low-gain amp that has a really low noise > > figure, and high IM rating, rather than a high gain amp. The one I'm > > measuring with is an ARR P144VDG. I did also try it with an angle > > linear GAASFET unit, which gave me about 2db worse performance in all > > three cases.
The Angle Linear units typically have only 16 dB of gain, which should be just the right amount to fully overcome the noise temperature of the following receiver without driving it into overload. Any less gain & your total system noise figure may still be degraded by the noise temperature of your receiver, any more & the receiver will be susceptible to overload from strong signals. 16 dB of gain is a nice happy medium IMO. Bob NO6B
