Martin wrote:
> But wouldnt it be much better to eliminate the hiss by modifiyng the
> audio-amp of the TS-850 ( or any other radio) itself, or,
> if the audio-amp just amplifies the hiss that is
> produced somewhere else, to prevent the hiss from being fed into the
> audio-amp?
Well, manufacturers frequently produce "quiet" receivers
by filtering out most of [noise AND signal] energy above ~1 kHz.
Typical cutoff starts at 1 kHz with ~15 dB attenuation at 2.7 kHz.
This removes most of the noise, but unfortunately removes
most of higher speech frequencies.
You may wish to try higher-order [~8] low-pass filtering.
That would preserve most of the speech,
while removing unwanted part of spectrum.
Maxim has some easy-to-use IC filters.
73,
Sinisa YT1NT, VA3TTN
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