Zum Radio Board as a Duplex Repeater.

[G0JSV]

I have a Zum Radio Board which is connected to a Yeasu FT-8900R. In simplex mode everything works as expected although only Time-Slot 2 is available. I would like to configure the Pi-Star software in Duplex Repeater mode but this isn't working. I can hear DMR traffic on both timeslots concurrently using 2 different radios (Retevis RT3 and RT8) such as TG80 on TS1 and TG840 on TS2. But when I TX nothing registers on the Dashboard and the status lights do not change on the Zum Radio board to indicate a received transmission. On the radios, the red TX light flashes 4 times. I am using 2 different frequencies with a 9 MHz split. I have tried all the usual remedies such as changing the TX/RX offset. Also played around with the TX/RX Inverts. Also experimented with the MMDVM calibration tools. Also twiddled the 32 turn pots.

I also have a Dual Hat MMDVM board which has the 2 antennas and this works perfectly in Duplex Repeater mode. The Pi-Star settings are mirrored between the 2 boards in terms of Frequencies, split, colour code etc. The Zum Radio board seems to work fine for YSF and DStar when running in Duplex mode but DMR just won't play ball. Also tried changing lots of settings on the FT-8900R such as using a single VFO with a repeater split, setting the receiving band for packet. i.e. VFO A (Left) is set to the RX frequency and VFO B right to the TX frequency and you can force the receiving band for packet.e.g. Force left.

I did wonder if I needed to make any changes to the Configuration > Expert > DMR GW settings but I cannot locate any info on this section.

Tom.

[M1DNS]

If you change the simplex setting to duplex You'll need two radios, one for TX and another for RX.

Sent from my SM-G935F using Tapatalk

[G0JSV]

OK. Thanks for the info. It seems odd that the receive side is working perfectly. I am currently listening to a conversation on TG840 which is being received on a Retevis RT8 using a code-plug with channel 7 set up as TG9 TS2. Then on the Retevis RT3 I can hear traffic on TG 2351 using a code-plug channel 15 set up as TG2351 TS1. Both time-slots being transmitted from the FT-8900R simultaneously.

My DMR Startup options being; StartRef=4440;RelinkTime=60;UserLink=1;TS1_1=9;TS1_2=80;TS1_3=81;TS1_4=235;TS1_5=2351;

So near and yet so far.