Re: New V6 CW tone frequency

Dale Parfitt

It certainly sounds as though you need to calibrate  the BFO.  As is signals, are on the edge of the crystal filter.

When mine arrived sidebands were reversed. Calibrating the BFO fixed it instantly.


Dale W4OP


From: [] On Behalf Of rskarka@...
Sent: Thursday, May 28, 2020 7:06 AM
To:; robert.skarka@...
Subject: [BITX20] New V6 CW tone frequency


Yesterday I received my new uBITX v6 full kit and assembled it. After a short function check (could hear some CW and FT8 signals), I installed CEC firmware and Nextion display. Everything worked right out of the box, but later I noticed, that when I tune to CW signals, the audio tone is very high. When I tune the HF for strongest audio signal, the audio tone is around 5khz, and when I change the frequency to get the tone lower, the signal disappears before getting down to the range of 1kHz.

For testing, I tuned to a strong CW station in LSB, USB, CWL and CWU. The highest volume for each mode was approximately:


7029 kHz LSB

7033 kHz CWL

7023 kHz CWU

7025 kHz USB


With SSB modes I can tune the tone frequency down, but also the signal is stronger at higher frequencies than 800Hz



So far, I didn't do any calibration, and right after uploading the CEC firmware, I downloaded the eeprom data with the ubitx manager software.

Could this be a frequency or bfo calibration issue? Im not sure, because it is mostly a problem in CW modes, and I thought the boards come calibrated from the factory.


Should I go back to the stock fw and display to run the calibration procedure of the V6 firmware with the web spectrum analyzer tool?


Something else to check? I have an HP/Agilent Oscilloscope, but the last calibration of that was 2003, so not sure how accurate the frequency counter of that is.


Thanks for help,



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