Re: A minor bug in the ubitx circuit

Ashhar Farhan
 

Russ,
The dashes dont seem long enough on the sidetone though they are transmitted properly. The dashes sound like blips. What is happening is that as a number of square waves pass through the filters caps, they charge up to an average of 2.5v (average of 0 and 5v). The 2.5v DC at the input of the LM386 DC saturates the chip and the audio input stops being amplified. The caps diacharge as soon as the sidetone ceases. The cycle repeats in the next dash. The dots are small enough to be finished before the DC rises enough to saturate the LM386.
- f

On Fri 6 Dec, 2019, 6:17 AM Russ KR0EHM, <russ@...> wrote:
How does this problem manifest itself? Just no CW tone at all or something else? My CW is working on relatively new v5 board so wanted to make sure. I’ve noticed it is a bit lower than I expect it to be (100-200 Hz) but that could be my BFO off, correct?

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