Instructions for use: F5ZLR – DMR Repeater
Digital Mobile Radio – BrandMeister
Transmission 430.075 MHz – Reception 439.475 MHz
Colour code 1
Slot 1 talkgroups TG9, TG208
Slot 2 talkgroups TG9, TG2086, TG20887
http://f5zgm.f8kfz.org:19389/index.php – Dashboard
- The repeater has effectively two channels (slots) available at any one time. If both the slots are active, the possibilities are communication exist only in breaks between the activity on a selected slot.
- In each slot there are a fixed number of Talkgroups, so that activity can be divided into the available different groups. Talkgroup 9 is local to the repeater, and the rest are channelled through Brandmeister servers to the connected groups. 208 is France National, 2085 is Aquitaine region. There are other talkgroups like 2350 on slot 2 and 235 on slot 1 available as dynamic talkgroups.
- Normally we would begin our conversation on the centre of activity, which in France is Talkgroup 208. On making a contact here, we would normally advise a QSY to a chat channel which in our case would be Talkgroup 2085 – Aquitaine. On the UK talk groups we start on 2350 slot 2 and move to 2351 or 2352 on the same slot.
- If your correspondent is on the same repeater, you can both QSY to TG 9 slot 1 and continue to talk. However if Talkgroup 208 continues to be active you can go to slot 2 Talkgroup 9 instead as slot 1 remains occupied. However paragraph 1 applies.
- If an alternative talkgroup is suggested, using a group call on any talk group on slot 2.
- At the end of any group call activity please make a group call to 4000 to receive “Not connected”, thus to make free the repeater for other calls.
- To test your transceiver on the repeater, you can make a private call to 9990 at the same moment as you speak to receive a reflection of your call as you release the transmitter key.
- There two types of Talkgroups: Fixed and Dynamic. The talkgroups listed above are fixed and made available in permanent transmit on F5ZLR. However behind the scenes there are the dynamic talkgroups that are user activated. These talkgroups require a short blip on the PTT to activate them, and they remain active for 10 minutes only. On slot 1 the talkgroup 937 (Francophone WorldWide) is available, and on slot 2 UK Talkgroups 2350 (UK wide), 2353 (UK Wide Chat), and 23887 (France bridge to C4FM).
Technical data:
Transceiver pair – Motorola GM 350 4 channel models. Internally modified to give flat audio in and out to the accessory socket on the rear. For details of how this is achieved there are various resources on line.
Accessory socket links are as follows. 5. Tx Flat Audio, 3. PTT, 7. Ground, 10. +12v in, 11. Rx Flat Audio.
Arduino Due (pronounced doo-ay as it is Italian) is compiled in Windows from source on the github/g4klx. Again the information about this is well documented.
The Due is connected to the Raspberry PI 2, in our my case with Ubuntu Mate 16.04.02 as the operating system, with the MMDVMHost software and .ini file compiled within.
The Due is completed with ZUM 1.0 board with on-board txco, connected to the transceivers. The repeater is finished with a repurposed AX25 power pack into a case for the 19″ rack. Because of the expected high duty cycle a 220v fast fan has been employed across the whole interior keeping everything cool. The duplexer is 8 cavity Katherein model tuned giving less than 1db in losses, which is good. Consequently the transmitter send 8 watts to the dual band antenna. It was original intended to share this antenna with a remote receiver for the existing R2 VHF repeater 40 Kms away, but the diplexer permitting the UHF and VHF systems to share was deemed too lossy, so the remote receiver has been turned off for the time being, leaving the repeater to run perfectly.
