my DMR notes RE: tonights tech night
There was some interest in DMR, other digital modes as well, from tonights technical net. The first radio I bought was a BTech DMR-6x2 specifically so I could play with DMR immediately. Since I've owned this radio since before I was licensed I thought I'd share some info and maybe provide a path for others to get into DMR. We're lucky here in Washington that there is a really large DMR repeater network available for us to interact with and the DMR community is very helpful and active.
Information on DMR specific to this region can be found at https://www.pnwdigital.net
... and they just updated their website so now I cannot find anything. I'll provide direct links:
http://www.pnwdigital.net/welcome.html <-- This is kind of a step by step to get associated with PNW Digital and what the network does. How to obtain a radio ID and some other bits of info required to "get on DMR".
http://www.pnwdigital.net/quick-start.html <-- For those that want to read less.
http://www.trbo.org/docs/Amateur_Radio_Guide_to_DMR.pdf <-- For those that like to read more.
Besides the Pacific Northwest DMR repeater network you'll quickly see the word "brandmeister" in reference to DMR. PNW DMR is _not_ part of the Brandmeister network. What's the Brandmeister network? It's another DMR network of "repeaters". I put repeaters in quotes because, from what I can tell, most people access the brandmeister network using a hotspot.
Hotspot? It's a small box that is network on one side and radio on the other. The network side uses the internet (your home wifi, starbucks, etc.) to attach itself to the brandmeister network. The radio side uses a simplex frequency at very low power which you tune your radio to. Now you're accessing the worldwide brandmeister DMR network at .(point)5 watts using the Internet. And, that's about all I will type about that as I've not played with it and I don't own a hotspot. Just to add... The PNW DMR network is a c-bridge network and they support the use of hotspots via the HamWAN. That's as far as I understand those words as I've not played with HamWAN either.
How do I use DMR... There is a PNW DMR repeater on Cougar Mountain and I'm able to get into that repeater with DMR better than the SnoVARC repeater. DMR is half the width of analog FM plus it's digital so that helps with low power. Ignoring how DMR works on the commercial side (it was developed by Motorola for commercial radio use) let's only focus on the amateur community and how it works for us...
oh, and this is my interpretation based on my experience with PNW DMR as your experience with DMR may be different and especially if you use the brandmeister network...
PNW DMR has set-up a number of "talk groups". A talk group is used to trigger how many repeaters in the network you want to "turn on". For example, if you key-up on Washington 1 you will light every repeater in Washington state. Want to talk locally using only the repeater you're currently tuned to? Then use a local talk group. Want to test how your signal is? Use the Parrot talk group (yes, it repeats what you said back to you). The PNW DMR website explains what talk groups are available and what they are used for. Neat huh?
Now the bad news. DMR radios are a bear to program. In order to key a talk group you need to know the frequency, offset, and tone of the repeater. Standard stuff right? OK so here where it's not standard. The talk group you want to talk on is configured as the repeater details, the talk group ID, the color code, the time slot, and probably a few other things I'm forgetting. And each time you want to use a different repeater you need to enter that talk group again with the new repeater info. My DMR radio has 1,326 "talk groups" programmed into it because each talk group is duplicated on every PNW DMR repeater. But there is the good news...
The PNW DMR site has a website where you can download text files, CSV really, of the talk group configuration. With a bit of knowledge on how to manipulate text files you can use these to load the talk groups into your radio memory slots above or below the standard analog repeater list SnoVARC uses. That's basically what I did to get my radio programmed and now have a process in place it takes me ~10 min to get an updated list from PNW DMR and load it in my radio. Happy to help anyone here.
Digital Monitor or "promiscuous mode" - Turning this on in your radio let's you monitor, or scan, every talk group on the repeater. If someone is talking on Washington 1 or Local you'll hear them and then can switch to that talk group and respond. That's how a DMR radio can "hear" every talk group. You've got to have the radio set to that talk group in order to talk on that group though.
I'll stop here otherwise this could become a novel. I've always got my 6x2 with me at club events as it's my main radio. If you want to see it or want more info please just ask. I'm not an expert but I'll share what knowledge I have.
Oh.. and if you want to get a DMR radio I suggest the AnyTone 878. It's the most feature packed of the affordable HTs and is well supported within the PNW DMR groups.io page. The 6x2 is "ok" but is lacking a couple features of the 878 I now wish I had. Hope that is helpful and if you see some info in here which is wrong please correct. I stayed up later than I intended writing this so I expect there are some errors here and there. 73