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Old August 26th 07, 07:39 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jul 2006
Posts: 158
Default Sun noise


" The coax only has a loss of 1 db for the length I am running it. I doubt
that at 2 meters I would see any benift of putting the preamp at the
antenna. It is as easy to get a 1 db or less noise figure at 2 meters as
it is to make any preamp and the 221 does need some help on the receiving
side.
From the articals I have read the beam width of most any single antennas
at 2 meters is wide enough the ground noise will override that ammount of
loss.


I think 1dB is a little optimistic for 75' of 9913 coax, it is in reality, I
suspect, nearer 1.5dB.

Any loss ahead of your preamp adds directly to the noise figure of the
system so the best NF that you could ever have is 2.5dB plus a little form
the 221.
Also 20dB of gain in the preamp sounds like a sure way to produce intermods
in your radio.

Regards
Jeff


 
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