New DMR Users – a note about RX group lists ..

I’ve seen several MotoTrbo codeplugs come my way with multiple Talkgroups listed in the RX Group List.  A recent Post by Karl on North West DMR  reminded me of this stupid and pointless practice that i’ve seen, I’m mainly putting this out there for new users who start are starting programming codeplugs.

You can only transmit on one Talkgroup at a time (apart from the ‘AllCall’ group of which more, later)  – but you have the ability to recieve any one of up to 15 Talkgroups.. sounds good, until you realise that if you are using something like Talkgroup 9 on a DMR-MARC repeater, the only traffic you will be expecting or interested in, is also going to be on  Talkgroup 9  – you wouldn’t listen to the next channel up for a response on FM would you ? or you wouldn’t open your IF passband right up and so you heard the rest of the channels on the band would you ? so why do that on a DMR repeater ?   You would likely get confused  (i certainly would) –  if you were talking on s22 but you heard a QSO on s19 just like it was on ‘your s22 channel’ does that make sense ?  NO !

I Imagine that much of the confusion this practice *does cause* are one of the main reasons for talkgroup confusion, and new users being ‘told off’ for being on the ‘wrong talkgroup’  Yes you might receive the right talkgroup *as well* but you won’t easily know who is responding to your call unless you see the correct talkgroup pop up when some other voice pops out of the speaker at you.. it could be someone at the other side of the planet talking to someone else, and they won’t hear you and, worse still, if you are scanning (depending on how you set your scan list) and the set stops on a channnel that has one of these unwanted spare talkgroups in the RX group list and you TX back  – the chances are You Will be TXing on the wrong TG and possibly not notice until you look down at your set’s display, or someone complains, so you see its a ridiculous state of affairs, yet these faulty codeplugs still crop up. don’t use them, or if you do, tidy up the RX Group list properly.  All RX group lists in codeplugs downloaded from this site have single entries in the RX Group list..

If you get a codeplug given, check the RX group lists have only one entrythe same as the TX talkgroup only !

-Hax-

All work, text and images © GB7MB

5 Comments so far:

  1. Great tip and when I checked my RX groups one had 4 entries in it. Now tidied up – better to be safe that shouted at ☺.

    BTW: my initial code plug came from a downloadable DMR start up code plug source – not here might I add. It got me started and I have added to it and personalised it but I never thought to check RX groups.

    Thanks guys.

    Steve

  2. When I checked my RX groups, *all* of them had several entries. A couple had *many* entries. This codeplug came in a new rig and was programmed by the retailer. What did I know? It was my first dmr rig and I only realised the situation when I screwed up my nerve and made my first foray into programming. It sure explained why I kept hearing all sorts of weird stations on Local S2!!!!!

    Now I have a dilemma. I’ve a new rig, again pre-programmed. I’ve not yet heard stations that don’t ‘fit’ the talk groups I listen to but that doesn’t mean I won’t! Until I have the programming cable + software and can take a shufti at the code plug, I won’t really know I’m set up right. At the very least, I’ll be renaming three talk groups. As it came, I had no idea what three of the talk groups actually were. By switching between rigs I’ve identified one of them.

    The second, imaginatively named “Europe S1”, still eludes me. There are fourteen talkgroups listed in the DMR-MARC database using slot 1 in the European region. Assuming the talkgroup is in English, that narrows it down to 2. Logic will take me no further: either I wait until I can look at the codeplug or I transmit for a second while looking at the dmr Last Heard web page. When my callsign appears, I’ll be able to look at the entry for that transmission and read off the screen what talkgroup I was using. What a sad state of affairs that I have to do that on a professionally programmed rig.

    The last mystery? It’s appears as America S1 and here are three regions with America & S1 in the database. I’m guessing it is N. America TG 3 S1. That’s the talkgroup which recently became one to be exclusively used by America: *we* can’t use it and DMARC has unlinked it so’s only America can. Not really useful having that TG in my rig, I’d be better off programming in my local FM analogue repeater so’s I can keep an ear out for my chums on that mode. Why not?

    But don’t worry, I get by fine mostly using Local TG9 S2, UK-Wide TG 235 S2 and WW English TG13 S1 for checking into the Monday net. [Rule of thumb: S2 is for UK operations, S1 is for operating outside UK. Using S1 for inside-UK operations (a) blocks the S1 ‘channel’ for TGs that need it (b) will eventually severely limit your operating privileges in DMR. ]

    The moral of my story is that it is wrong to assume your rig has been programmed right -or even correctly for your repeater- just because it came new and pre-programmed. Needless to say, you need to be even more cautious with pre-programmed second hand rigs. If you have any doubts about your code plug, get it checked out by an expert. Don’t ask me, I’m a newbie who is -like Paddington- ‘a bear of little brain’.

  3. Glad it helped a little Steve and Vic – i must stress I ‘m no expert, but i question the wisdom of this practice particularly on Amateur DMR repeaters.

    Simplex, slightly different. I have some DMR simplex channels, (mainly calling freqs) set to receive all talkgroups between 1 and 15 (inclusive) – someone asked me a while ago, why dont we all just use TG1 for simplex, my answer was, ‘we probably should, but the present convention says 9’ – i do this in case someone is using TG1 or whatever .. also i TX on the ‘AllCalls’ talkgroup – which is going to be mentioned briefly soon.

    I totaly agree Vic with rigs arriving with poor codeplugs, and un-features like multiple TGs in the RX group list. Yes, dealers are often very busy with large numbers of professional users, so sanity checking every codeplug is not an viable option, but see later for my thoughts on this.

    I think many DMR users have fallen into the trap of thinking that these sets are Amateur sets, in some respect, it really is in fact, PMR gear in the classic sense, but instead of taking the time winding coils, and doind PCB work and tuning things (and ordering xtals ?) – that time must be invested in the 21st century equivalent .. a PC.

    Ultimately, the burden for correct operation falls down top the individual Amateur to check before use, not all amateurs nowadays have the necessary skills sadly, but the other problems i see with this include :

    a:) The Amateur may have no knowledge of basic DMR concepts.

    B:) expecting someone with no prior experience in radio programming, (or maybe basic PC skills) to correctly program a modern commercial digital transceiver is a recipe for disaster.

    c:) finding suitable answers, guides and and tips can be tricky, and many sites that *should be the site to go to* are poorly presented, confusing, or lack important local relevant info.

    d:) DMR-MARC repeater keepers need to publish lists of all recommended Talkgroups on their repeaters.

    e:) there needs to be a default codeplug available for each area of the country, maybe tied to the nearest DMR repeater or activity clusters and it needs to be checked by those who understand them, and deemed fit for purpose.

    I would like All sellers of DMR gear that already send DMR sets with codeplugs, to send the set supplied with these ‘standard area codeplugs’.

    Vic, i have seen DMR codeplugs that would make your ears curl, trying to dechiper between mistakes or intentionally ‘bad’ can be a long and tedious task, so i decid to keep it simple, I’m a simple Guy. so I’m often told 🙂

    i have a inexplicable urge for a marmalade sandwich now though ..

  4. I have a newish Mototrbo DP4601 that has been programmed by the dealer for my local dmarc repeater HM that I have not used yet as I am completely new to digital & my knowledge about it is very little in fact extremely little, So I decided to do some research before using it in order to try & learn as much about it as possible rather than dive in head first causing any problems to other users, After having read many reviews, reports and comments of the enigma of this digital world with its digital new language of wording that would appear one must rush out to buy a specially published digital dictionary as the more I read about it the more I was getting confused & being in my 70’s that’s easily done, for example, on buying the radio I was told I would first need a code plug before the radio could be used so i spent the whole day searching the radio for the plug hole. Sorry about that, just my little joke, anyway, its now quite some weeks after having purchased this radio & I still have not used it, I have had it switched on & on scan many times & have heard very little or should I have said most of the time nothing at all on the repeaters, So I am now wondering just how many other dmr owners are out there experiencing this digital enigma.

  5. I’m beginning to understand the entire DMR thing but have one question.
    I have the TERA TR7400, and it has talk groups and RX groups which I can add to both from a large list. Plus I can name them as I want to.
    The question is regarding RX groups. It is required to have a Rx group programmed since there is already zones that coincide with talk groups.
    IE. I have my company frequencies programmed in the radio and have the RX group programmed, but all my ham radio freq. do not. I have not had an issue transmitting on either systems.
    Can you feel me in on that…

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