The SNR is set at the antenna. There is a persistent desire to move the
selectivity closer to the antenna, however....
With modern "bullet-proof" front ends, filtering can be delayed and done at
i-f. In fact, with H-mode mixer front ends, the IMD in the following filter can
be more of a limit on signal handling than the mixer. See:
http://martein.home.xs4all.nl/pa3ake/hmode/roofer_intro.html
Imagine trying to build a multiplicity of such filters to cover the 160-meter
band.
Wes N7WS
On 12/22/2016 2:44 PM, K1FZ-Bruce wrote:
Thanks Mirko,
Very Good information. What is needed is to reduce noise lower than signals.
73
Bruce-k1fz
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