Re: ubitx v6 board only
Almost all receiver problems with the uBITX line of radios from HF Signals are solved by following the attached link:
(459) uBITX (v6) Frequency Alignment - YouTube
The above is from Ashhar Farhan, the lead developer for HF Signals, as well as one of the founders.
The most critical is the BFO adjustment, as that impacts receiver sensitivity.
I hope this helps.