Go to content

DMR-ZA is located in South Africa and is part of the DMR-MARC network, a worldwide network of dedicated digital amateur radio repeaters located in over 37 countries with more than 11040 registered users, originally set up by a group of Motorola engineers who are also active radio hams.

Now approaching more than 400 repeaters worldwide, each is able to provide local, regional and worldwide repeater coverage.

Repeaters on the network are connected all the time (24/7). TRBO radios have great voice quality, great coverage and extended battery life all in LESS THAN A 1/3 of the channel bandwidth of a traditional analogue FM repeater with TWICE as many voice channels! This offers you a reliable and scalable choice in connectivity: local, regional, national and international.

There's much more than that though - the network allows two completely separate QSO's at the same time, a unique feature made possible using Motorola's "Time Division Multiple Access" (TDMA) technology. This enables a TDMA repeater to divide transmissions into two discrete and pre-selectable "talkgroups", routing them appropriately to others monitoring the same group anywhere around the world. Effectively, this means two completely separate voice channels are possible within one standard 12.5kHz frequency allocation - highly efficient use of the spectrum!

Time-Division Multiple-Access (TDMA) preserves the full channel width and divides it into alternating time slots that can each carry an individual call. Motorola maintains that two-slot 12.5 kHz TDMA-based systems, provides 6.25 kHz equivalency. This means that two seperate conversations can be handled by the one repeater, on the same frequency but using two different "channels".

TG1 is for Worldwide Calling and for QSO's less than 2 minutes. This is not a talkgroup to ragchew on!

TG13 Worldwide English is for English speakers. TG13 is available 24/7 on many systems and here you can make international calls and there is no time limit other than being courteous and not monopolizing the talkgroup, allowing others to use it. (That's the advice of any wide area talkgroup including TG3 North America). Remember, TG13 is not for USA-USA or USA-Canada calls - TG3 North America is for that. If you want to call the UK, Australia, New Zealand, South Africa, or English speaking hams in other countries use TG13. PLEASE DO make international English calls on TG13.

Make our fellow overseas hams feel welcomed to join us. Let's key up on TG13 from time to time by announcing our call and asking for any international traffic using plain language. (Don't call CQ CQ CQ - this is not HF).

Back to content