CW operation uBitX #ubitxcw


Hi all,

So far hadn't touched my uBitX v3 for a while. This week I started building the AGC-kit I had ordered a while ago and added another 3.5mm audio connector to make a separate connection for a paddle.

Have not used CW as of yet, first have to practice  bit more ;) So far my operation have been limited to the higher bands (20+) and FT8.

Now that I was playing around and recently also obtained a GP5-SSB I was able to listen to my signal using a dummy load. Listening I discovered that when the key or paddle is not pressed you hear a faint tone (keypress is much louder) Is this because I am so close to my uBitX and is it the zero beat of the 700Hz  that I am hearing?




Beats me as to what you might be hearing. The lowest frequency made by the ubitx is 12 MHz. Okay possible that it might have some carrier leakage, way down there. Yes its possible you might be hearing result of carrier leakage mixing with bfo. Its likely no issue at all.

Extra connector for cw? Please note that ubitx modulates cw based upon one pin going into raduino. Even stranger,  cw sending is based upon having a resistor in series with key or paddle. On off keying uses a 4.7k resistor you likely already installed. To use paddle, you need 2 added resistors of a particular value for dit and dah. Okay, you could host these resistors inside with an added connector.

Assuming you are adding ND3T agc, yes that should be nice. Enjoy your journey with ubitx.


Daniel Conklin

I noticed that too and I think it's just the first oscillator stage which runs constantly when transmitting. 


I just added another connector with the two resistors so I wouldn't have to adapt the cable of my paddle. Guess somehow it should be 'doable' to automate the detection key or paddle as the measured values on the pin are different. But with the latest GUI interface of Nextion and CEC firmware is pretty simple and quick to change the key/paddle.


What I am hearing is the same tone as the CW tone but much fainter but I have my GP-5/SSB maybe 4 ft away from my uBitX. It is like some background noise when the key is not pressed and it seems to increase slightly in frequency before the uBitX returns to RX.

My uBitX has been performing pretty well on FT8 so am not too worried about it. My setup was with an efhw antenna in the attic and reached about 6400 miles on 10m back in March with a measured output of about 2.6 Watts maximum. 
As I am pretty new to HF, still have to get used to finding QSOs on the bands. ;)

Guess it was a typo about the AGC, I have the kit from Kees based on the ND6T design, also have the click-fix kit.

73s de John, K5GT