Multi Mode 70cm DIY Repeater Build Project Pt2

Well I finally had some time with COVID-19 raising its head again here in Australia to get back to the 70cm Repeater build as mentioned in Pt 1

Lets layout the hardware, before I get to my call for help.

The radios:

2 x Tait TM8235 just like the one I have hosting my UHF Winlink gateway

The modem:

1x Repeater Builders MMDVM v4 & Raspberry pi hat sitting on 1 x Raspberry Pi B3+

The duplexer:

flat pack UHF cavity from the 409 shop

Now to my problem

I can’t make it work!

Below I have collated the info from the Tait manuals as well as what I currently have as my setup.

Radio DB15 Pins

15 Ground

13 Audio Out

12 PTT

8 +13.8V Body switched

7 Audio input

6 RSSI indicator

MMDVM DB9 Pins

2 TX Audio

3 DVM Inhibit (active low)

4 RSSI

5 PTT

6 RX Audio

8 Ground

9 +13.8V

The actual problem: I have hooked it all up and on the pi-star home page - it NEVER receives any valid DMR signal. I have used the audio pot to turn down to make sure there is no clipping.