[RFI] High Noise Levels on 80m
n6kj.kelly at gmail.com
Tue Dec 19 12:26:44 EST 2006
I'm trying to figure out why my noise levels are so high on 80m, but
not on other bands. I'm hoping someone can provide me some clues.
In a 500Hz CW bandwidth, I typically have about S0 or S1 noise on all
bands except 80m. Sometimes noise jumps up to as high as S6 on other
bands, but most of the time it is pretty low. 80m, on the other hand,
is S7 to S8 24/7/365.
I have a 3 element SteppIR and a 2 element 40m yagi. My 80m antenna
is an inverted vee with the apex at about 50 feet and the ends at
about 10 feet. The SWR on the inverted vee is good, with 1.1:1 at
about 3550 or so.
Question 1 - I know that 80m has more noise than 40m, but should it
really be 6 or 7 S-Units higher than 40m? That seems like a lot.
Question 2 - Normally, the noise level in a 2.4KHz SSB bandwidth is
considerably higher than in a 500Hz or 300Hz CW bandwidth. I can see
the S-Meter drop several S Units when I switch between wide and narrow
bandwidths. I do NOT see this same drop on 80m. There is no drop
when I switch bandwidths or if there IS a drop then it is less than 1
S-Unit. This doesn't make sense. Can anyone explain to me why this
More information about the RFI