Talkgroup/Channel/Contact typical configuration

ryancousins

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I'm having a little difficulty wrapping my head around best practice for codeplug configuration. Let's say you want to interact with one repeater that has multiple talk-groups used on it. I would think you would only need to create one channel with the repeaters TX&RX freq, and then program all the talk-groups separately into the radio and then choose which talk-group to send to on that one channel. But the way I always seem to see it is that one repeater channel will be duplicated for each talk-group. So you might have ten channels that are all the same repeater freqs but each with a different talk-group associated with it. Now it makes sense to do it this way as it makes it easy to rotate through your talk-groups just like you would analog channels, but it seems like duplicating data is never the best way to do things in the programming world more generally. It seems like rather than create a bunch of duplicate channels and associate each one with a TG, it would make more sense to create a bunch of TGs and associate them all with the same TX/RX pair. That way they all refer to one piece of data, but none of the CPS's I've seen do it that way.

Another slightly related question- on my Anytone D878UV CPS, talkgroups and contacts are separate entries. That makes sense if contacts are only private calls, however, you can make contacts group calls also. Should the talkgroup ID be made into a contact also?

I apoligize for my total stupidity :)
 

ryancousins

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I know and it seems silly. Why even have channels AND talkgroups then? I know its different but TGs are a bit like CTCSS/DCS codes in that you wouldn’t duplicate and store a conventional frequency a hundred times just to apply a different PL to each one. You’d create one instance of the frequency and select different PL as needed. So why even have TGs be a thing on non-trunk systems if you need a channel for each one anyways?

I’m really mostly making sure I’m doing it correctly even if it seems like a strange practice. I just kept thinking “am I really supposed to create several instances of the same channel?” If so than so be it!
 

slicerwizard

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I know and it seems silly. Why even have channels AND talkgroups then? I know its different but TGs are a bit like CTCSS/DCS codes in that you wouldn’t duplicate and store a conventional frequency a hundred times just to apply a different PL to each one.
You would if you had different user groups on a community repeater and you wanted to communicate with different groups.

You’d create one instance of the frequency and select different PL as needed.
I suspect that many would not.

So why even have TGs be a thing on non-trunk systems if you need a channel for each one anyways?
Because multiple groups are sharing that repeater. Because the protocol you're using (DMR?) uses talkgroups.

I’m really mostly making sure I’m doing it correctly even if it seems like a strange practice. I just kept thinking “am I really supposed to create several instances of the same channel?” If so than so be it!
It's simple from the radio's point of view. For each channel, you provide TX, RX, DCC, slot, talkgroup, etc. Easy peasy...
 

ryancousins

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I appreciate everyone's help as I try to understand all of this. A lot of good points made. So on my AT-878, there is a Radio ID section where you can enter multiple radio IDs. What is a situation where you'd need to enter more than one? Wouldn't you just enter your DMR ID and that's it?

Also, on my GD77 all TGs and contacts just go under "contacts" but on the 878 there are separate sections for contacts and TGs. I'm thinking TGs would be where group calls go and contacts would be where private calls go, but in the CPS you can make a TG private and you can make a contact a group call so I'm not sure what that's about. Is this so you could create a TG that just corresponds to a private call, so you could essentially create a "Talk just to Bob" channel? Conversely, when would you create a contact that is a group call?
 

chief21

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In the '878 CPS... The Talk Groups section is where you would list any digital group call (or private call) that you would want to access when building a digital channel (in the Channels section); The Contacts section is where you can download all (or nearly all) of the currently-issued amateur DMR ID's in the world. AFAIK, the ID's in this section can not be used to build a channel - they are for screen reference only.
Typically, group calls relate to "open channels" that others could also access, such as you would find on an analog repeater. A "talk just to Bob" channel would be known as a private call. A "talk to Bob and his buddies" channel would be known as a group call.
 

wyShack

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If you have two repeaters on same frequency but different PL, many would use two 'memories'-one for each repeater. Talkgroups are somewhat similar -each one is a different 'logical' channel. As an example, if you have US and the 'tac' talkgroups it is easier to switch 'channels' than try to flip into the menus as you drive down the road. I agree their is little change in the setup -but that is how things work in the digital radio world. In fact most radios are set up by 'talkgorup' rather than channel -it is transparent to the user.
 
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