Don't use narrow CW filters by default http://30cw.wikidot.com/forum/t-15748447/don-t-use-narrow-cw-filters-by-default Posts in the discussion thread "Don't use narrow CW filters by default" - So many good reasons NOT to do this Wed, 11 Mar 2026 13:37:42 +0000 http://30cw.wikidot.com/forum/t-15748447#post-6118244 Re: Don't use narrow CW filters by default http://30cw.wikidot.com/forum/t-15748447/don-t-use-narrow-cw-filters-by-default#post-6118244 Fri, 09 Jun 2023 15:04:47 +0000 G0FOZ 8541264 The original idea was elabourated in this paper Binaural receiver however that operates on the IQ level.

I had a simpler idea. Spit the mono audio out of the receiver into two filters. One a low pass filter and the other a high pass filter. Use around 700Hz ( or preferred beat frequency) as the centre frequency. Feed the two outputs to left or right ear/headphone. Whilst I did originally knock up a circuit for this, since I feed the audio into a sound card anyway, I just knocked up the circuit digitally with GNU radio companion. Something like this (logical then grc):
grc_fil.png
grc_spacialiser.png

And what a broad SSB appears like across L/R speakers.

grc_spacialiser2.png ]]> http://30cw.wikidot.com/forum/t-15748447#post-6113630 Re: Don't use narrow CW filters by default http://30cw.wikidot.com/forum/t-15748447/don-t-use-narrow-cw-filters-by-default#post-6113630 Wed, 07 Jun 2023 14:33:43 +0000 G0RQQ Keith 4137826 I would be interested to know what audio processor you use to generate the “stereo” effect.

]]> http://30cw.wikidot.com/forum/t-15748447#post-6046792 Re: Don't use narrow CW filters by default http://30cw.wikidot.com/forum/t-15748447/don-t-use-narrow-cw-filters-by-default#post-6046792 Tue, 04 Apr 2023 08:13:49 +0000 G0FOZ 8541264 Agree with this.

Even when the band is a little busy I find using an audio processor that spreads the audio across L+R headphones by frequency can help you "see" where a signal is :-)

]]> http://30cw.wikidot.com/forum/t-15748447#post-6042898 Re: Don't use narrow CW filters by default http://30cw.wikidot.com/forum/t-15748447/don-t-use-narrow-cw-filters-by-default#post-6042898 Fri, 31 Mar 2023 16:41:25 +0000 M6KET 8059732 True this just widened the filter right out on my KX3 and it seems to bring in many signals I feel I would have missed as I trawl through the band .

Good mini session this pm working MW0 (POTA), Donal in Cork and Simon F4GXT

John

]]> http://30cw.wikidot.com/forum/t-15748447#post-6022699 Don't use narrow CW filters by default http://30cw.wikidot.com/forum/t-15748447/don-t-use-narrow-cw-filters-by-default#post-6022699 Mon, 20 Mar 2023 14:52:00 +0000 G4OJW 7450444 Listening around I so often hear stations missing answers to their CQ calls as they don't take time to do careful listening, or are using narrow filter and a station replies off frequency outside of the narrow pass band. We have been given the best filters in our head, our ears and our brain. Let's use them! It's not to say that filters cannot be used when really needed, but by default, start out with a wide filter. It's also not a bad thing when someone calls a little off-frequency, so long as they aren't causing QRM, as any QRM is not likely to zero beat with both stations… and so if QRM develops one station can ask the other to QSY up or down to continue. Plus, is not the sound of static nicer than the sound of a narrow filter? Yes, local noise is a good reason, and also strong QRM near the frequency, but I think often OPs use narrow filters out of habit and miss out a lot?

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