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What I want to do is add digital voice (DMR, D-Star, Fusion) capability to an existing dual band mobile or HT. Similar to adding APRS functionality using APRSDroid and a bluetooth TNC. Reading here, I understand this can't be done purely in software yet.

I'm looking for something that I think is a bit like the DV hotspot devices out there like the JumboSpot or DVMega. As I understand it, those devices let an existing DV radio get onto a network when an repeater isn't available. Their "upstream" to the DV network of choice is over the Internet, their local connection to the DV radio is UHF or VHF.

Imagine a DVMega-type device that is capable of encoding/decoding AMBE packets and generally running a particular DV protocol. This is using a TNC to talk to the radio and is also talking over bluetooth serial to an Android phone. The phone would have a UI for picking talk groups and other DV-specific items.

My question is: Can anyone point me at devices that do this, or technical reasons why what I'm looking for can't exist?

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  • $\begingroup$ That's a pretty bad shorthand. You might as well use "banana" as shorthand for "any fruit people eat". Maybe "DV" is what you want, for "digital voice". $\endgroup$
    – Phil Frost - W8II
    Commented Oct 14, 2018 at 23:57
  • $\begingroup$ @Phil: Agreed. Just changed DMR -> DV above. I'm new enough, I didn't know whether DV or "digital voice" would be understood as meaning "DMR, D-Star, or Fusion." $\endgroup$
    – kbyrd
    Commented Oct 15, 2018 at 2:25
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    $\begingroup$ So what is your question? $\endgroup$
    – rclocher3
    Commented Oct 15, 2018 at 20:21
  • $\begingroup$ I would like pointers to an actual device that does what I described, or a collection of things that I can put together to do it, or more likely a bunch of technical reasons why want I want to do won't work. $\endgroup$
    – kbyrd
    Commented Oct 15, 2018 at 20:24

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I doubt such a device will ever exist, I'm afraid.

The problem is the TNC-radio interface. Packet at 1200 bps is pretty forgiving, you can hold your radio up to a computer or phone's speaker or mic and it'll work, more or less.

Packet at 9600 bps, on the other hand, requires a connection deeper inside the radio because there is circuitry (or nowadays, digital signal processing) in the radio that's designed to make voice sound better, but that same circuitry distorts digital signals.

The various digital voice modes use encoding in the range of 4800 to 9600 bps or more, so I expect that the same problem will make it practically impossible to engineer a dongle or soundcard interface without a radio capable of tapping in before the audio filtering circuitry/DSP.

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  • $\begingroup$ "The problem is the TNC-radio interface. Packet at 1200 bps is pretty forgiving, you can hold your radio up to a computer or phone's speaker or mic and it'll work, more or less." Ahh! I didn't realize that the TNC wasn't higher a rate. $\endgroup$
    – kbyrd
    Commented Jan 30, 2019 at 15:17

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