Anders SM5NNO has drawn attention to a published fix for low levels of drive on SSB with BITx transceivers from Mr K P S Kang (VU2KR / VU2OWF) on this blog. While the mic gain fix relates to the BITx40, it translates readily to the uBITx.
Reference
An update
André PA3EIV confirms that the above fix (by Mr. K P S Kang VU2KR works 🙂
He changed the value of R65 to 4K7 and the value of R63 to 10 Ohm using 1206 surface mount components (desoldered from scrap prints).
He now has, on normal voice volume, 10 watt’s out on 20m. RV1 is turned counter clockwise for about 75%. André uses a Baofeng microphone.
That was a great modification. I tried with extra microphones which I had in my junk box. None of them gave more than one watt out when whistling in the mike.
Then DF3FY told me that I should use the mike which came in the kit.
It does a great job itself but one has to speak very close to the mike.
Thus, I changed those two resistors and now the situation is corrected.
I got a good report from my fellow local ham who said the audio is excellent. Even with the mike soldered directly to cable 🙂
Kai, OH3WE, Lahti, Finland