Re: DMR information

Paul Smith

Cool BEANS! Chas! tnx


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From: <> on behalf of Charles W. Powell via Groups.Io <doctorcwp@...>
Sent: Friday, September 14, 2018 8:42:19 PM
Subject: [4SQRP] DMR information
It was brought to my attention that perhaps everyone on the list is not familiar with DMR, so i will do my best to give an explanation of what it is and what it does.

DMR = Digital Mobile Radio.   Essentially it is a radio that uses a digital voice encoding to optimize human speech for radio transmission.

So why would we want to use it?  Well, because it is also includes a way of accessing other radios and users world-wide through the internet, using inexpensive radios, and allows a number of ways to gain access.  DMR can "talk" or work through DMR repeaters in your area, or radio-to-radio, but the really exciting part of it is that there are now inexpensive "hotspots" that allow you use your home internet connection or mobile phone to access the network.  In the case of the Four States QRP group, it would allow us to have ad-hoc conversations regardless of where each of us is located, formal or informal nets, or even "spotting" nets to see who is on the air with frequencies, times, etc.  If our Talk Group is approved, we will have a platform for any or all of these activities, plus any others that fall within the realm of our amateur licenses.  (Even if it's not, there are other places we could congregate on DMR.)

I was skeptical about DMR until I got into it.  On the way to Dayton (Xenia) this year, I talked to hams along the way and even arranged to have lunch with a fellow ham in St. Louis.  There are folks who have more knowledge in their pinky finger than I have in my entire head.  I have spoken with Eric, 4Z1UG, as though he were next door. (Some of you might listen to his podcast, QSO Today).  I have done a lot of listening on the Baynet Talk Group, and picked up a lot of information that I would otherwise have had to spend hours researching.

Is there a downside?  Yes, sort of.  The radios are proprietary, so programming requires some planning and figuring out a "code plug" that will do what you want it to do and go where you want it to go. It also generally requires a computer and a cable for programming.  It is a bit more complicated than just entering a frequency and PL tone.  It's more that you have a target (Talk Group, or Individual), a "color code" (roughly equivalent to a PL tone), a time slot, so your radio knows which half of the conversation(s) it wants, and finally a frequency that allows you to get where you are going.  I didn't think it was going to be nearly as much fun though as I found it to be.

Is DMR Amateur Radio???  Well, yes and no.  It does involve RF, but it is also a voice-over-IP protocol using the Internet. I think of it more as a means to an end than "real radio." But in the end, Amateur Radio is about communicating and DMR does a good job of facilitating that.  Think of it as having a "local" repeater that any one of us can access at any time, regardless of our physical location.  That's why there is some excitement over the prospect of involving the Four States QRP folks in our own talk group.

If anyone has any questions, ask me and I will do my best to answer.  I'm not an expert, but hey - that's how we learn.


Chas - NK8O

P.S. If you want to investigate prices, look at the most popular radios, such as the TYT MD-380 and the Anytone D868-uv.  For hotspots, check out the "OpenSpot" and look on HRO for "Zumspot"  I will stay away from others because I'm not as familiar with them.  Personally I have the Anytone and Zumspot. The Zumspot is based on a Raspberry Pi Zero, so the whole thing is about 1" x 1.5" x 2.75" or so. 

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