Re: [amsat-bb] Receiver impedance mismatch

["Howie" <hdefelice@xxxxxxxxxxxxxx>]

"....the input to VHF and UHF receivers
 designed for best SNR do not present a good match to 50 Ohms. "

Yes, this is often the case with low noie amplifiers. Placing a filter in
front of a very low noise amplifier will increase the system G/T not only by
altering the impedance seen by the amplifier, but also by directly adding
the insertion loss of the filter to the noise figure of the amp. Fom a
practical standpoint, unless the filter is very high Q (as in a cavity
filter), the amplfier mismatch will probably have a very small effect on the
filter characteristics. At least this has been my experience..

Howie
AB2S

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