Success! Maybe there's more that can be done at Q6, but it is
MUCH improved with a 10k resistor to ground at the output of C51.
Still Could be multiple causes, so still worth experimenting. I'll
dig the scope out and see.
There's a ground point very near C1, so you can scrape the
coating off of that and bridge a 10k chip resistor across the two.
Photos enclosed.
John K0JD
On 12/21/2017 11:55, Jerry Gaffke via
Groups.Io wrote:
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But
Q70 gets powered up on RX, and Q6 gets powered up on TX.
That power switching is really disruptive.
Might leave them both powered up, then the DC bias resistor should
work fine, if you somehow kill the microphone
But given what we got, I'm leaning toward the FET clamp on rx
audio.
Reducing the size of C52 on Q70 might help get the pop over with
quickly.
In addition to the audio pop in the phones on rx, the uBitx may
have the Bitx40's? carrier burst on tx.?
? ??/g/BITX20/message/33707
Allard has been fixing some of this with delays in firmware.
If we can get by without a special interrupt library in the code,
the sketch will be much easier to
understand, add features to, and port to other processors.?
So I'd prefer to fix the rx pop and tx burst with hardware hacks.
Jerry, KE7ER
