I wanted to purchase the "Radio Tone repeater controller (actually some years ago!) it didn’t work, there was supposed to be a code sent with your radios touch tone key pad to energize or shut down the unit, also to turn off the roger beep, so I sent it back.
I was not able to find another more rely-able unit so I set about diy or making my own.
After some time (due to human conditiion) I was able to implement the Velleman Digital Echo Chamber.
At first I had problems with the miserable pads and traces being too close and falling off the board, I solved this with an incredibly low temp of my soldering iron.
After two or three boards $10.00 x ??? now that I was so close I was not able to trigger the inboard vox on the walkie talkie as the internal anti-vox was not allowing any quick keying! I need this also for fast paced drill and local neighborhood emergency faux disaster work, I also want the back scatter type sound (not too much distortion), to act like a beacon for hams and part 15 cb activity.
So what I need to do is either turn off the anti-vox but have no idea where it is since there is no schematic or find an exact replacement of the echo chip HT8972/b80500048G Hopefully this will add a non-distortion delay at least 500ms.
I’m sorry to say that I think you might have the wrong forum.
This is specifically for the Velbus range.
If you’re looking for the Velleman forum, it has moved to