Mark,
This topic refers to uBitx. Both B40 and uB have similar issues as the
audio preamp and mic amp are identical.
Raj
At 09/01/2018, you wrote:
toggle quoted message
Show quoted text
Is this Mod for the Bitx-40 of
the Micro-Bitx ?? Starting to get a bit of a muddle reading posts
now on here , Not knowing what version of BITX there for ..
Mark? 'Gw0wvl' ...
- On Tue, 9 Jan 2018 at 4:29, Raj vu2zap
- <rajendrakumargg@...> wrote:
- Farhan,
- I have been thinking of diode switching in the audio stages. The TX
12v can block the RX preamp and vice-versa.
- I have to get back to town to try!
- Raj
- At 09/01/2018, you wrote:
- >i have been trying to hack out the tx pop. it is a far more
intricate problem than it does seem at first. to cut a very long and
painful story short, i am not yet there. but i have a partial solution.
- >
- >add a 470uf (or a 220uf) capacitor in parallel to C50. The C50 is
the 1uf capacitor that feeds the detector signal to the audio pre-amp.
Increasing this to 470uf, prolongs the 'switch on' time of the audio
preamp just enough to not hear the TX-to-RX thump.
- >
- >can someone else too try this out?
- >
- >i call it a partial solution because it doesn't suppress the
rx-to-tx pop (which is not as bad as the tx-to-rx pop).
- >
- >- f
Raj vu2zap