New video explaining DMR

[Excalibur]

Well, apart from wishing to TX illegally, you've probably just summed me up in a nutshell.

I'll get the radio, I'm slightly anal and don't make impulse purchases, so will do plenty of research first, now you've explained the tier system that will help with which set to buy, and if I get into trouble I'll give you a shout

Sure, you can PM me when you get the radio and I'll tell you how to get all the information you need. Maybe a future video of mine will help anyway.

At the moment, the latest big thing in DMR seems to be the TYT MD-380. You can get it for around £115-120 from China. I've got one on the way to review, so if you're subscribed to my YouTube channel (hint hint ) you'll see when my review comes out.
Alternatively, there are radios like the Motorola DP3600, the DP4800, and the Hytera PD785. If you don't want to spend a lot, it's probably better to go for one of the chinese radios like the TYT MD-380, because the programming cable for this type of radio is usually cheap (£5-10) and the software is usually free. (As opposed to the programming cable being around £50 and the software not being free).
But then on the other hand, the motorola radios are the most commonly used by commercial systems, and therefore they can follow motorola proprietary tier 2 add ons which are trunking. They aren't part of the standard, so only motorola radios can follow this type of system. It's called capacity plus and linked capacity plus in case you're interested. Commonly used on systems with larger amounts of users.
And the motorola radios are super rugged compared to chinese stuff. The DP3600 and DP4800 are IP67 so you can take them swimming for half an hour and they should be fine.

I can listen to the capacity plus system with my TYT-MD380 you just have to program all the frequencies in alongside the talkgroups and other information. Then add all the channels to your scanlist and it works just as fine - of course it isn't really trunking since its not following the instructions given from the repeater to what channel to go to instead it's just looking for activity on each channel quickly.

[radiosification]

I was careful to say you can't follow the system rather than you can't listen to the system, to make sure it was accurate (:
You can scan small systems but It's not very practical to scan linked capacity plus systems with many repeaters on each site. There is one system I know of with 6 repeaters on just one site. That would mean you have to scan through 12 channels.

[Excalibur]

I was careful to say you can't follow the system rather than you can't listen to the system, to make sure it was accurate (:
You can scan small systems but It's not very practical to scan linked capacity plus systems with many repeaters on each site. There is one system I know of with 6 repeaters on just one site. That would mean you have to scan through 12 channels.

Sorry I misread that.

With the TYT-MD 380 you can have 31 channels to a scan group, although I don't know what the scan speed would be like as I haven't managed to find a system big enough like that to try to scan. I do however know that regular scanning is good on the TYT and is much faster than the typical Baofeng snail pace scan rate.

[kr0ne]

Nice vid radiosification, I think you managed to explain quite a lot without making it seem like it!

A question about the different tiers though... is trunking solely available in tier 3? Reason I ask is I keep hearing about amateur DMR repeaters being linked together... Is this not trunking? Or is it a bit of a lower-tech bodge that just looks a bit like trunking?

[radiosification]

Nice vid radiosification, I think you managed to explain quite a lot without making it seem like it!

Thanks!

A question about the different tiers though... is trunking solely available in tier 3? Reason I ask is I keep hearing about amateur DMR repeaters being linked together... Is this not trunking? Or is it a bit of a lower-tech bodge that just looks a bit like trunking?

Very good question. I'm sure a lot of people are thinking the same thing.
Amateur DMR repeaters in networks such as the DMR MARC network use something called "IP site connect". This is not trunking, because the timeslots are not allocated dynamically, but you're right about them being linked in some way. The repeaters are linked by IP and play the same audio on groups that are set to be linked.
This allows people to talk to people on other repeaters, and it also allows them to roam across repeaters which are all connected to the same talkgroups. When radios roam, they select the strongest repeater automatically.
For example here in London, there are a bunch of repeaters linked up on talkgroup 8. If you drive across London and have roaming set up correctly, your radio will listen to each different repeater on a the same talkgroup (and on the same slot) as you pass through its coverage area.

I'm planning to cover this topic in a follow up video.

[BK]

The latest edition (210) of Ham Radio Now has an introduction to DMR and explains a bit about how IP Site Connect works.
https://www.youtube.com/watch?v=GfUp4zJVw_s

[kr0ne]

Ah right, I get you... I think! So, when 'roaming' between repeaters I take it there is no real smarts involved - i.e. it simply repeats everything to everyone all of the time rather than the repeaters being aware of where any particular handset... sorry, radio ... actually is on the network?

[radiosification]

Exactly, yeah

[radiosification]

Well, actually when I think about it, sort of exactly. It only repeats some talkgroups. Roaming talkgroups, Uk wide, Europe, Worlwide English and so on. There are talkgroups that are local only (on the repeater you're connected to) or connect only to a certain function such as an echo service for you to test your audio.
But yes, any talkgroup that is set to be repeater works like that.

[BK]

OK, so let's say your local DMR repeater has the following talk groups set up;
TS1,TG1 = worldwide
TS1,TG2 = europe
TS1,TG13 = worldwide english
TS2,TG235 = UK repeater
TS2,TG8 = regional
TS2,TG9 = local

If you wanted to hear all activity through the repeater, would you have to program 6 channels and scan them to receive all 6 talk groups?

Is the repeater permanently connected to all these groups simultaneously? If so, what happens if there's incoming traffic (over the network) on the worldwide and the europe group at the same time?

[radiosification]

You wouldnt necessarily have to programming a channel for each talk group. DMR radios have Group lists, so you assign a group list to a channel. In the group list, you put all the talkgroups you want to monitor, and it will receive any of them. On Motorola radios the limit is 16 talkgroups per list. Other radios may have different limits.
For example in my radio, I have a group list called "amateur" which I use to listen on all of the amateur DMR repeaters because they all use the same groups. I apply that same list to slot 1 and slot 2 for each repeater I want to listen to.

I don't know what happens if there is activity on multiple linked talkgroups at a time. One will be played and the other ignored, but I don't know what decides which one is chosen.

[BK]

Thanks for that. I've been reading up a bit more and it looks like some talk groups are user activated, i.e. they only become active on that repeater when you key them up, with a 5 minute timeout. Other talk groups are always active, and in that case it looks like whichever group is in use on that repeater will have priority, with a 5 second hang time (although you might have to wait for another talk group to go quiet before you can key up the one you want in the first place). In the event that the repeater is not in use but more than one 'always on' talk group is active, I don't know which group will take priority.

It turns out you can direct dial repeaters on DMR MARC too, for example our local repeater GB7EE in Edinburgh is TG931

[radiosification]

Yeah, they have a lot of clever features on DMR MARC

[kr0ne]

Is EE online now then? Gonna have to splash out on a new radio methinks!

[BK]

Is EE online now then? Gonna have to splash out on a new radio methinks!

EE is already connected to the DMR MARC network, but only transmitting into a dummy load until the NoV application is approved. The live monitor shows Allister has been accessing EE and connecting to talk groups http://www.gb7dd.co.uk/gb7ee/
Definitely time to invest in a DMR radio