You know, I have to confess: CW isn’t my favorite operating mode. It’s ok; sometimes I tune down to the CW portions of the ham bands and copy it for a while just to keep my hand in, but not too often. Consequently, another confession: I’ve not looked really hard into SdrDx’s CW handling until today. When I did, I found there were improvements that could be made, and, because I’m somewhat compulsive, I went ahead and made them, and you’ll find them in the 2.12r OSX beta that’s available for download as of right now. But don’t stop reading yet, please.The first thing I did was some work on the high and low adjustment ranges of the CW mode demodulator envelope; now allows from -10 to -1500 Hz, allows from 10 to 1500 Hz. These are sane ranges; previously, it was a little weird, and I apologize for that.
The second thing was change the demodulator envelope adjustment from 100 Hz/step to 50 Hz/step. This allows you to create a properly centered demodulator envelope of an odd width, such as 300 Hz, or to cut the bandwidth all the way down to 50 Hz — a little extreme perhaps, but amazingly usable if the received station is stable.
Lastly, I experimented a bit with the audio notches to see how to best tailor the audio, and I found that with the Q of a notch set to about the third hashmark from the right of the Q scale, the notch was narrow enough to sit right on the upper edge of the demodulator envelope. I’ll give a detailed example:
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