ptt ubitx v6 ext amplifier #v6


Hi, does anyone have a solution to connect an external linear amplifier control circuit to ubitx v6.1, thanks.


Hi Brunetto,

I’m sorry I  took so long to respond.
Here is my successful uBitx v6 PTT connection to the XDT-PA70.

The PTT on the XDT-PA70 can be triggered in two different ways depending on the version of XDT-PA70 you have.

  1. some versions use a contact closure
  2. my version uses a 5vdc signal that draws 2 ma.

My version of the XDT-PA70 amplifier requires the 5vdc to trigger the PTT (transmit) signal. You can tell if your XDT-PA70 is this version by locating the opto-coupler chip (EL 817) see photo (PA70 ptt opto.jpg).
These instructions only apply to this type of signal. If you do not have the opto coupler EF 817 then your version will require a contact closure to indicate transmit and somebody else can direct you to a contact closure on the uBitx v6.


The 5 volt signal is generated by the uBitx and can be found at the junction of C150 and R 150 called T/R on the schematic. see schematic (uBitx TR schematic.jpg) and photo (ubitx TR location.jpg). you will notice I just soldered two wires red 5vdc on the junction of C150 and R150 and black on the other side of C150 (ground).

I connected this to the ptt plug that came with the XDT-PA70 see photo (PA70 ptt opto.jpg) red to pin 1 and black to pin 2 see (XDT-PA70 schematic.jpg)


I hope this helps