[amsat-bb] Re: Filters and Preamps Question

Joe Fitzgerald jfitzgerald at alum.wpi.edu
Mon Oct 19 16:33:19 PDT 2009

>  what's the preferred
> order?

As ever "that depends".  In the specific case I was involved in at
Worcester Polytech, we found that we could get the best trade off by
putting the preamp at the antenna then knocking down the out of band stuff
with the filter between the preamp and the receiver.   The losses in the
filter hurt your system noise figure much more if you go ant -> filter ->
preamp -> receiver

If the out of band stuff is desensing your preamp, well, that is another
story.  At +12 dBm for the ARR GaAs FET we were using there was no
problem, even in an urban environment.

-Joe KM1P

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