Hi Tim
You wrote < In VHF/UHF and EME weak-signal CW work, a lot of operators also
liked listening with wider RX filters too, often preferring Gaussian filter
shapes, and letting their ear pull the signal out of the noise.>
I may be just normal because my experience on EME CW is very different. I
used to have 4 2MXP28 when I was living in Brazil, the location was very
quiet and the activity back in the 90's was SSB and CW. Several times the cw
signal was arriving at noise level, turning the filter to 60Hz the signal
copy was Q5, hard to copy with 120 Hz and no copy 250Hz or up. When the
signal is above the noise anything goes.
The issue with narrow bandwidth is the maximums speed you can copy using CW,
that is because the BW for 30 wpm is two wide for narrow filter,. Using 50
Hz you can copy no more than 13 wpm whiteout losing the signal. EME
operators use 10 to 13 wpm on CW.
Is quite common to see a contest operator without experience on weak signal
running 30 wpm or more on 160m.
160m is a weak signal band, if you don't learn that you never will advance
on the DXCC. When we have high QRN we turn he radio off. However during the
winter we sometimes have just no noise on 160, it is better than 144 MHz,
because the only source of noise on 160m is atmospheric noise, if you don't
have atmospheric noise, there is no noise. Manmade noise manageable, my HWF
as example, the manmade noise is attenuated 50 db below the HWF antenna
gain at -43 db. The manmade noise end up below the MDS of my radio. As a
result it is common for me to use 50 Hz, Doug NX4D sometimes uses the SAFF
filter on the Orion II at 20 Hz, in both cases the weak signal at noise
level signal just pop up out of the noise.
73
N4IS
JC
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