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Steve Stroh N8GNJ's avatar

Brian - Good points all. I'll be exploring these ideas and more in the future article in ZR.

For MOTOTRBO repeaters and radios, there IS a data capability to use one (or both?) of the two slots for data... but that seems proprietary to MOTOTRBO radios - requiring MOTOTRBO radios and software that communicates just with MOTOTRBO radios. Hytera did the same thing. But I haven't seen anything equivalent for "generic" DMR repeaters and radios, so I'm guessing that there may be some Amateur Radio experimentation necessary to enable that capability, perhaps an enhancement of the DMR mode that's implemented in MMDVM.

Yes, data over conventional FM repeaters works, and can work well, but in my (admittedly limited) experience to date, the biggest issue of using data over a voice repeater is that it's a continuing "Mother, May I?" issue with the user base / owners of those repeaters to use data. While they give lip service to the idea of experimentation with data, they don't want to offer "blanket permission" for data use sufficient to make the data capability truly usable (and reliable). Thus we get into the absurd situation of actively considering the creation of NEW repeaters that can be dedicated to "data first" usage... while existing repeaters continue to sit idle 99% of the time.

And agreed, the duty cycle could theoretically be an issue, but probably no more than some voice nets that can go for an hour or more of continuous use. Certainly any new repeater that's set up for data use would be prudent to set it up for enduring high duty cycles.

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Tony Langdon's avatar

As someone who has experimented with multimode repeaters and hotspots for years, I do see a lot of potential for adding data capabilities to FM repeaters. I already have a test system running 5 modes using a MMDVM (currently on a dummy load until I get an antenna up and the paperwork sorted). The system cleanly switches modes, and having data modes alongside the voice modes (including FM) would be neat.

I also have extreme demands on VHF/UHF antennas from monitoring multiple frequencies to supporting APRS and intending to run some sort of data service. Being able to aggregate data services, including repeaters that can receive data such as APRS payloads over M17 or MMDVM-TNC, while transmitting traffic from remote Internet stations would be neat.

An additional factor here is the terrain lends itself to a lot of "hidden station" issues on simplex, which duplex should mitigate, especially when the repeater output isn't tied up with other traffic..

Lots of experimentation ahead, and I'm looking forward to having a play.

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