uBITX V5 not working PTT #ubitx-help

Varga Tamás

Hello all!

I would also have a quick question. I built an ubitx V5. My problem with it next is when I want to switch to trasmititng with the small micro switch nothing happens. If, on the other hand, I press PTT on a USB cable with Pocket RXTX software over USB, it switches to transmiting immediately.

My question is , is there any other place where the PTT switch is available besides the pin 5 of the contorls connector (ORANGE wire) and the GND (BLUE wire).

I would like to ask if I put a switch between the spindle pin 16 (T / R) and GND, would it work as a PTT switch?


That is, if you look at the PTT switch, the orange wire of the VFO panel and the 8 pin audio connector (blue wire) of GND. However, 
if I short this then there is no switch to transmit. Measurements made so far: -GND, ie blue cable to orange cable in RX mode is 4.75V. when I press the switch, the high mark on pin 16 of the mainbord does not appear. Amin is also 0 V by default. - But if I use software PTT on my phone via the arduino CAT cable, it switches to 5V and goes to TX mode. I also include arduino switching. here is in PDF My question is, where do you think I can take the PTT linkage off?
So do you think I could do an additional circuit or something to make physical PTT work?

Sorry, my English!

Tnx and 73's Tamas

Gary Anderson

Hello Tamas,
PTT is handled by A3 on the Arduino Nano.  I would check that your PTT wiring is driving the A3 pad/pin low with respect to the GND on the Nano when your PTT switch is pressed.
(this may be what you mean by "Amin is also 0 V by default."
If your wiring is correct and that pad/pin does go LO (logic low) when PTT is pressed, it is indicating a faulty Nano that needs to be replaced.  Easy to do and many here will help you if you have concerns/issues.
It is fairly common to have an Electrical Over Stress / ElectroStatic Discharge event that damages a CMOS Input/Output buffer. 

You don't want to wire a switch that shorts T/R to ground.

By the way your written English is very good.  "Sorry, my English!" was the only clue you are not a native speaker.