Just as I finally began to get comfortable with ham radio's highly successful digital mode, DMR, the technology expanded even further, along with its reach and complexity.
For amateur radio, DMR has basically been a version of Motorola's MotoTrbo system, with access to hundreds of worldwide repeaters linked by the internet and divided by talk groups. (Engineers used to call this "ROIP," Radio Over Internet Protocol, but the term seems to have faded away.)
Talk groups are worldwide, national, regional and local on the DMR-MARC system, plus there are a couple of wildcard channels (TAC 310 and TAC311) that let users in different areas talk without tying up all the repeaters that would otherwise be involved.
Typical MotoTrbo repeater system (Photo courtesy of VA3XPR.net) |
My first exposure to DMR was in 2014 when I met Steve Tripp, K1IIG, who is considered one of the fathers of DMR in Connecticut. That day, he was visiting the Waterbury Amateur Radio Club repeater site at the Prospect firehouse, while scoping out locations for another DMR repeater.
I was hooked on DMR that day and I knew it. The selling point was one of Steve's radios - the Connect Systems CS700 UHF portable - which is fully functional on the DMR-MARC system at a cost of less than $200 - a very affordable price compared to most Motorola equipment.
DMR-MARC is based on specific Motorola protocols. It doesn't give users the flexibility to create on-the-fly talk groups or the ability to join the network from a computer rather than a radio (such as Echolink allows.)
Connect Systems CS700 radio (Photo by Pete Miller, W1AMJ) |
Then came Brandmeister - a highly flexible DMR bridging system with access via the internet while using a popular USB dongle that turns laptops into a digital hot spots for portable radios.
Brandmeister, if the name didn't give it away, is a German creation with thousands of worldwide users and its own talk groups. It also has a very attractive and busy interface page, showing real-time numbers of repeaters, users, dongles and hotspots on the air. You can even click on the "hose" section to listen to live audio.
At this point, most Brandmeister users are accessing via computer rather than by RF, and this has a lot to do with the success of the DV4 mini dongle, marketed by Wireless Holdings of Florida. There seems be few direct repeater affiliations in the United States, but in Avon and Vernon, Conn. two new Brandmeister UHF machines have gone on the air as part of the PVRA system.
Screenshot of Brandmeister dashboard |
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Suffice it to say there is enormous infrastructure behind DMR, so if you are a purist who believes radio and computers shouldn't be highly integrated, it may not be the mode for you. But give it a try - you might become addicted.
Echolink is also based on the internet! Can talk to the world with just a smartphone and a wifi connection.
ReplyDeleteEcholink is also based on the internet! Can talk to the world with just a smartphone and a wifi connection.
ReplyDeleteIt can be argued that an elaborate internet infrastructure takes away from the purity of the radio hobby. Certainly in a disaster, it's bad practice to rely on internet connections to work correctly, since they can be a point of failure. There is also Hamsphere, an elaborate ham radio internet simulation that involves no real radio at all.
DeleteThe DV4mini was never meant to be on Brandmeister. Only when another ham hacked the DV4mini software to work with Brandmeister did WH finally produce software to work with it, and the original DV4mini software dev accused the Brandmeister folks of "code theft" and have created new DV4 products that are hardcoded to use DMR+ now and not Brandmeister. The SharkRF OpenSPOT and DVMega-Pi hotspots are much more reliable and better-sounding on DMR than the DV4mini.
ReplyDelete