Today on DMR…. Pi Star and dispelling some myths.

Now we have the most comprehensive front end for the various MMDVM-style modules, it is important to realise that the PiStar is NOT the software that drives your modem but the interpreter for what passes between your modem and the digital world.

I heard a conversation yesterday about the various updates that led me to believe that many people think it does a lot more than it does.

MMDVM as it had popularly come to be known, is a compilation of modules in a complete interpreter for most digital modes developed by Jonathan Naylor G4KLX.

One of my repeaters F5ZLR was operational on DMR with an Arduino Dué and Raspberry Pi long before the arrival of Pi Star, which was a little more difficult as I had to address the computer in SSH, so the arrival of Pi Star was very welcome.

Pi Star now gives full control over the modem via the mmdvm.ini, the parameter file that it requires to run. Pi Star then interprets the data that arrives at the modem from the network or the RF connection and displays it in a pleasing form than we can understand. The administration part of the Pi Star gives access to the parameter file or files, that once changes have been made, have to be uploaded to the modem computer, that has to be reset with the new parameters before it will operate correctly.

There are a number of types of modem, either as plug-in or stand-alone, clones and originals, each with subtle differences, pin configuration, simplex or duplex, each requiring the same basic software to accommodate these differences. Pi-Star had become the one-size-fits-most solution, but requires great care to correctly adjust to the modem inside. I recently spend an hour on-line with a friend, setting up his hotspot, that required a little patience and careful reading of the interpreted data that the Pi Star was feeding me. Because the hotspot was a sealed unit the modem type wasn’t clear, but the end result was a working hotspot with a slightly adjusted receiver, finding the correct modem type from the presented data list, and by setting the RX offset slightly positively in the mmdvm parameters.

So when updating your Pi-Star, your actions will largely only update the front-end, with all the data tables that Andrew Taylor has created for the dashboard to access. Updating the modem is not so easy, but possible, but unless your modem is particularly old is not really necessary unless you are going to try pocsag or one of the less known modes for which Jonathan has provided new modules.

If you wish to understand more on the mmdvm then go to https://github.com/g4klx where you can check the dates of the updates to the various modes used.

My verdict on the PiStar? Awesome! Many Thanks to Andrew and the collaborators in the project who developed the original dashboard in Germany.

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f5vmr

Radio Amateur and Professional radio operator and IT professional for 40 years so don't say I know little of what I say.

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