We feel the need to clarify some misinformation currently circulating internet forums regarding our TETRA repeater GB7TX.
PLEASE NOTE: Repeaterbook.com is wrong, GB7TX is listed as a DMR simplex node. Using a DMR signal will not work with this repeater.
GB7TX is a Motorola* (Branded Cleartone*) CM5000 DMO repeater (Type 1A).
That IS the repeater part. Mobile and handheld units register with the repeater and their transmissions are then "repeated" by the repeater. It is a single frequency, it receives on one time slot and transmits on another time slot.
We use a Motorola* MTM800 to provide the linking.
The MTM800 is connected to a Raspberry Pi 4 which is running Allstar with MMDVM and Analogue Bridge to connect the repeater to the Phoenix DMR network. The Raspberry Pi also listens for SDS (Serial) messages from the MTM800 which it then passes (via a custom script) to the Pi to change talk groups.
The repeater default talk group is (DMR) TG844 which links GB7TX, GB7EB and GB7YL.
You can use other Phoenix talk groups if you wish, they are user activated via SDS codes**.
Because Allstar is running in the background you can also connect to other Allstar or Echolink connections (via SDS**)
Please beware the repeater cannot connect to DMR and Allstar / Echolink at the same time. This is to prevent non digital originating signals from being transmitted over the DMR network, TG9 will be displayed on the Phoenix K Dashboard. It is also the reason why (currently) Allstar and Echolink connections are outgoing only, all incoming connections are rejected.
The CM5000 and MTM800 (with the PI) are housed in an old DR3000 repeater rack case. The MTR5800 possibly??
What GB7TX isn't.
- It isn't a DMR radio hooked up to a TETRA radio. That would have to use another repeater to access the DMR network, GB7TX is directly connected.
- It isn't a DMR Repeater. Don't bother trying it won't work. - Search on the ETSI website for the DMR and TETRA specifications if you are in any doubt.
- It isn't a simplex node / gateway (either DMR or TETRA), it is a repeater that uses two time slots, see above.
* Motorola is a trademark of Motorola Solutions
* Cleartone is a trademark of Cleartone PLC
** We are currently reviewing the SDS codes to work in better with SVXLink TETRA repeaters. SDS Codes will be published on the GB7TX page