A few others have noticed this.  It seems from their posts that this only occurs

when using digital modes that interface the uBITX via analog audio input. 

SSB mode uses a different signal path than plain CW on a uBITX.  If you

are not seeing the RF output level variation using CW but are seeing it during

digital modes with audio interfaces, it may be that the audio input is changing. 

If this is the case, then it may be that the input is changing frequency and driving

your RF off frequency far enough for the IF filter to be blocking part of the

signal, or that it is driving far enough off frequency for the RF PA filter to be

affecting power output.  Both level and frequency are critical for digital modes

that are introduced to the uBITX as an audio signal.

Arv

_._

On Fri, Jan 15, 2021 at 6:05 AM Rubens Kamimura <rubens.kamimura@...> wrote:

For all,

I would like an opinion, I have uBITX v4, the RF power is oscillating, now with more intensity, as it is a QRP, I believe that a variation of 2 to 3 watts is not a good practice in the 40m (7074kHz) in FT8.

--

73's 

PY2PVB

Rubens