NQ5T:
>Except for the fact that I was talking about the NB and not NR :-)
But you also wrote:
"With a 2.4 Khz roofing filter in line, the DSP NR had virtually no effect on
the specific form/content of 75M garbage this morning."
Did you mean to write NB instead of "NR" above?
>To your point, I've come to the conclusion that while you're generally
correct, NR does add to SNR even at very narrow bandwidths. I found in
testing that NR will improve the apparent (S+N)/N ratio around 10dB even at
100 Hz bandwidth.
Simply not possible. 10 dB improvement at
100 Hz implies a noise bandwidth of 10 Hz, which
is far too narrow even to copy 15 WPM CW. If you
actually measured the S/N improvement, using the
procedure ARRL uses for their MDS measurements,
it would be much less than 10 dB. This is probably
due to the gain change NR causes which fools our ears.
73, Bill W4ZV
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