70cm Radio

We finally managed to get the programming software, radios and cables in the same room for the Motorola GM4340s we have. The radios are for doing 70cm packet data in Aberdeen, with them finally programmed and tested we need to make a computer radio interface.

The GM340 has an accessory connector on the rear, rather than hacking together something using the microphone jack we can use this. The connector is 0.1" pitch so we can just connect female pin headers to it.

Our connector needs to hook into audio in, audio out, PTT and ground. I soldered these connections on a strip of female pin header and connected them to two TRRS jacks that were lying around. I pulled off the PTT and a ground line to another block of female header so we could connect that to a GPIO on a pi.

With this hacked together connector we were able to do some packet between a pi and another radio.


It is Sunday, so that makes seven days of writing .

Reading: Diamond Age, Crooked Little Vein