Topband: more on noise

[Pete Parisetti]

I would like to thank all who have answered my question on noise floor in
dBm.
To summarise, it turns out that it is common (with a vertical antenna and
with narrow bandwidth on CW) to measure between -80 and-90 dBm. This place
my own suburban location in a pretty average range.

Now, as everybody else (by the way, the tread on "getting ore people on 160"
was really GREAT), I am trying to fight noise. And here I have another few
questions for the experts. I use a KC2TX coax receiving loop, which shows
good directivity (especially noticeable on man made, "digital" noise that I
get quite often), but does NOT seem to improve S/N on top band. The loop is
down about 40 dB from the TX antenna, but as I said, there is no noticeable
improvement in the intelligibility of weak signals. My questions are:

- wold a receive preamp improve things? I doubt, since noise would get
boosted as much as signal.

- could it be a problem of interaction with the TX antenna? I know that
resonating antennas must be decoupled from beverages and flags/pennants, but
I don't know about loops.

Again, thank you very much in advance for any wisdom.

73 Pete
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___________________________
Pete Parisetti MM0TWX - HB9DSU
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visit http://www.hb9dsu.com