Duplex Hat: Non-simultaneous TX/RX?

MMDVM_HS Hat hardware
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Joined: Wed Sep 23, 2020 4:38 pm

Duplex Hat: Non-simultaneous TX/RX?

Post by KD5GR »

Our Club has a Yaesu DR-2X repeater and a Yaesu "room." We also have a node on FCS reflector 3. I want to use a MMDVM duplex hat on a RPI3 B+ as a bridge from our FCS reflector node to our repeater, thus to our Yaesu "room." I set up the MMDVM to use the repeater output as the MMDVM receive frequency and the repeater input as the MMDVM transmit frequency. (The hat is located very close to the repeater.)

However, there is a problem. In order to have separate tx/rx frequencies, I must set the Pi-Star software as a "Duplex repeater." This causes the hat to act like a repeater, i.e. it transmits and receives simultaneously. Obviously, this won't work for our application.

I've tried unsuccessfully to find a way to make the hat transmit on one frequency and receive on the other frequency, but not simultaneously. In short, I want it to operate like a mobile radio.

Is this possible? If not, can the Pi-Star software be run on a RPi3, but without the MMDVM hat? The goal here would be to have the Pi-Star softwear control a 70cm transceiver instead of the MMDVM hat.


UPDATE: I found a fix. I can use a regular (not duplex) board and set it for "repeater." However, I have to use the "MMDVM_HS_HAT (DB9MAT & DF2ET) for Pi (GPIO)" radio/modem to make it work. I hope this helps someone down the line.
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