uBitX v4.3 calibration


I see someone else asked this question before, but the thread wandered off into BFO settings, shipping issues, and other things and never resolved this that I can tell. I built a BitX40 last winter and was thrilled with it. I made some hardware changes and some software changes to the Amunter sketch and have had a blast with that very capable radio on SSB, both fixed and mobile. Now I am finally getting some time to start work on a uBitX and I have one that was delivered to me last summer and is a v.4 board. It powers up showing it is v4.3 and sort of worked (only trying receive at this point), but the audio sounded terrible and was fairly weak. I made a slight adjustment to the BFO that helped a little with the pitch, then noted that everything was 1kHz off frequency as compared to another rig. The posted alignment instructions on the HFSignals website seem to refer to an older version of the software. This is what another user observed:

Menu: "Setup on?"
Menu: "Set Calibration?" 
If button-
Print "Set to Zero-beat,"
Print "press PTT to save"

Menu:  "Settings on?"
Menu: "Set Calibration"
If Button -
Print: "Press PTT & tune"
Print: "to exactly 10 MHz"
delay -
Then it goes into TX - and the PTT Delivers a sidetone -

and this is similar to what I am seeing. If I tune to 10MHz, and I supposed to zero beat with another receiver tuned to 10mHz? If I ground the orange line labeled as PTT, nothing happens. So...??




Something very similar happened to me trying to do frequency calibration. Yes 7 got it into transmit also. Somehow I did improve it.

Very important,  it was slow to dawn on me the display reflects ssb operation. When we go into cw, and see ourself on RBN note the frequency will be about 700 hertz higher or lower, depending upon whether we are in usb or lsb. The kd8cec website has a nice explanation here.

My board came with the bfo way off. With the nice narrow xtal filter, the bfo must he close to get much ssb energy into the passband. Patiently work this before thinking something is amiss. I needed to visit the web to find a typical bfo value to get close enough to set it. The ubitx receives wonderful with bfo aligned.


_Dave_ AD0B

Yeah Vic you want to calibrate the frequency display first. I didn't like using wwv for calibration of frequency. They have the intermittent carrier. I reloaded to a version 1.08 of kd8cec and tuned it to a Commercial AM station I figured a big station would have a much more accurate carrier than I would need. Once you do that then go back in and set the bfo to 11996500 or so and adjust it from there.

I tried the latest version of kd8cec, 1.1, but didn't find the option to run it on the 1602 display,

Vic see you down the log.


Playing more with the uBitX, currently “breadborded” (wired up with alligator clip jumpers) on the desk. I found that it is going into transmit during the calibration phase, and that appears to be intentional. In other modes the PTT switch acts normally. I tuned my main rig to 10mHz and, watching the pan adaptor screen, I moved the apparent uBitX carrier up to zero beat the frequency, alternating listening on USB and LSB, and now it seems right on frequency. Then I played a little with the BFO and it is sounding better. They really should change the instructions on the website as I have never heard that this is the way it is supposed to be done and that seems odd for a new or impoverished ham who would not likely have another rig with SSB capability to listen to.

I plan to play around in this temporary hookup and probably load the CEC sketch and see about converting the display. Then the big question of whether I start modifying the rig for spurs and harmonics or wait for the v.5 board.



I was baffled by this too. All a bit strange.

For uBitx V 4.3 calibration Here's what i did:

Change band to 20m, attach a dummyload, or a decent antenna for 20m, with a low SWR. Use Your frequency counter, then start the calibration routine - the radio will key up , then adjust so Your frequency counter reads bang on 20mhz.

After You do this, Things will be fall into place i suspect, including the BFO problems i bet You are having.

Yes, i know. This sounds wrong, but i could NOT get my uBitx to behave predictably until i did this. I actually thought i had fried it it was so unstable and off-frequency, then i did the calibration thing, but with the radio on 20m, and it all fell into place.