Number of static talk groups?

kd8vok
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Number of static talk groups?

Post by kd8vok » Sun Nov 11, 2018 8:41 pm

I'm new to DMR. Yesterday I received an Anytone 878 plus an original OpenSpot. After watching countless YouTube videos, I think I have most of it working.

I have a few questions about static talk groups. I'm wondering how many do most people use? Please tell me if I got this wrong - as I understand it, the advantage to the static talk group is it's always "on". So my OS will always broadcast conversations for the talk groups I select. Then if I have my radio in scan mode, it will stop whenever a channel that is programmed with that TG# detects a conversation.

So I was wondering what happens if I put in maybe a dozen static talk groups. Then they're all active at once. Does that mean the OS is transmitting all of those conversations at the same time? I'm just wondering how many it can handle at once.

310 TAC-310 USA
311 TAC-311 USA
312 TAC-312 USA
313 TAC 313 USA
314 TAC 314 USA
315 TAC 315 USA
316 TAC 316 USA
317 TAC 317 USA
318 TAC 318 USA
319 TAC 319 USA
913 English (world wide)
3139 Ohio
3169 Midwest

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zelthian
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Re: Number of static talk groups?

Post by zelthian » Mon Nov 12, 2018 12:25 am

First, no need to scan. Just put all the talk group in your receive group, and whatever transmits will come out your radio. Or see if your radio has a digital monitor feature.

Second, only one transmission can be happening on a talk group at any given time. If there are several talk groups "static" on a time slot/hotspot, first one to transmit "wins", and the others don't transmit.

kd8vok
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Re: Number of static talk groups?

Post by kd8vok » Mon Nov 12, 2018 2:08 am

Thanks for the reply. My programming software does indeed have an option called "Receive Group Call List". I created two different lists containing several talk group IDs. When I look at the options for the scan list, it seems like I can only add channels, not a the list of talk groups. And each channel can only be associated with a single talk group, not a group of talk groups. I need to do a little more research on Google to learn more about the Receive Group Call List.

So only one talk group transmits from the OpenSpot at a time, correct? It sounds like if I'm listening to a conversation, and I turn the channel knob up a few clicks (not scanning), then I won't hear anything even if the next channel has an active conversation at the same time. Is that correct? So I would need to hit the PTT once for the OpenSpot to switch to the new talk group.

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zelthian
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Re: Number of static talk groups?

Post by zelthian » Mon Nov 12, 2018 3:01 am

kd8vok wrote:
Mon Nov 12, 2018 2:08 am
So only one talk group transmits from the OpenSpot at a time, correct?
Correct. This is true of any hotspot or repeater.
kd8vok wrote:
Mon Nov 12, 2018 2:08 am
It sounds like if I'm listening to a conversation, and I turn the channel knob up a few clicks (not scanning), then I won't hear anything even if the next channel has an active conversation at the same time. Is that correct?
It depends on whether the first conversation continues. Assuming that's what you meant, then yes, this is correct, UNLESS the TG that is transmitting is in the Receive Group on the channel you end up on; then, the conversation would continue to transmit on your radio, even though the transmit talk group is different.
kd8vok wrote:
Mon Nov 12, 2018 2:08 am
So I would need to hit the PTT once for the OpenSpot to switch to the new talk group.
Not if there is a transmission coming from your openSPOT. You'd have to wait until that transmission ended. Then you could key up a different talk group. Then, once you're done transmitting, if the other talk group has traffic, it would continue to transit out of your openSPOT. You would need de-activate the first talk group (via Brandmeister Tools or the Brandmeister website if static, or by using the unlink command (TG 4000) if dynamic) to ensure you could transmit freely without interruption on a different talk group.

The problem is that, since any device (hotspot/repeater) can only transmit one TG on a slot at at time, and you can't control who's transmitting on that talk group, you can only assert control over your device by controlling which talk groups are active.

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oh3nfc
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Re: Number of static talk groups?

Post by oh3nfc » Mon Nov 12, 2018 11:37 am

About the Rx group list and AT 878. Since the older version 868 has rx group list available I don't see any reason why 878 should not. Try to look closer and you will find the setting.

73 de Veijo OH4VA

kd8vok
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Re: Number of static talk groups?

Post by kd8vok » Mon Nov 12, 2018 12:07 pm

Thank you for the info. This is very helpful. It sounds like having several static talk groups is not as useful as I had thought. Now I am imagining a scenario like this:

I have set up static talk groups 123 & 456. I'm listening to a conversation on a channel that is linked to talk group 123. There is a brief pause in the conversation. Meanwhile, a conversation begins on talk group 456. So the OpenSpot switches, and begins transmitting that conversation. My radio is still on a channel for talk group 123. So when the conversation resumes on 123, I won't hear it while 456 is active. Is that correct?

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zelthian
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Re: Number of static talk groups?

Post by zelthian » Mon Nov 12, 2018 1:05 pm

kd8vok wrote:
Mon Nov 12, 2018 12:07 pm
I have set up static talk groups 123 & 456. I'm listening to a conversation on a channel that is linked to talk group 123. There is a brief pause in the conversation. Meanwhile, a conversation begins on talk group 456. So the OpenSpot switches, and begins transmitting that conversation. My radio is still on a channel for talk group 123. So when the conversation resumes on 123, I won't hear it while 456 is active. Is that correct?
Short answer: Correct.

Longer answer: You can get around this by putting both 123 and 456 in your Receive Group List. Then you create 2 channels, one with 123 as the transmit talk group, one with 456 as your transmit talk group. You assign the "combined" Receive Group to both channels.

With this setup, you would hear 123 and 456 on both channels, then you just choose the channel you want based on the talk group you wish to transmit on.

In my radio(s), I have ALL my normal Brandmeister talk groups in one massive Receive Group (I call it "BM All"). I assign this receive group to all my hotspot channels. That way, whatever talk group I may have active on my hotspot (out of my normal selection), and whatever channel I have my radio set to, I'll hear what transmits out of my hotspot. I just have to remember to change to the channel of the talk group I want to respond to.

kd8vok
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Re: Number of static talk groups?

Post by kd8vok » Tue Nov 13, 2018 12:28 am

Thanks - I finally figured out the Receive Group List. I've been monitoring a few talk groups all at once. For about half an hour, both TAC 10 and TAC 311 were very active. So what I heard bounced back and forth between the two conversations.

This seems like a good method for casual listening. But back to your earlier comment, "The first one to transmit wins". So if I want to join the conversation, that sounds like it would be troublesome if I have too many static talk groups.

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zelthian
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Re: Number of static talk groups?

Post by zelthian » Tue Nov 13, 2018 12:51 pm

kd8vok wrote:
Tue Nov 13, 2018 12:28 am
But back to your earlier comment, "The first one to transmit wins". So if I want to join the conversation, that sounds like it would be troublesome if I have too many static talk groups.
Exactly. A lot of folks in the early days of DMR in Ham Radio figured this out all too quickly when they set up repeaters with a half-bazillion TGs on it, and wondered why no one could maintain a conversation. :D

PA3BZT
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Re: Number of static talk groups?

Post by PA3BZT » Sun Nov 18, 2018 2:30 pm

zelthian wrote:
Mon Nov 12, 2018 1:05 pm
Longer answer: You can get around this by putting both 123 and 456 in your Receive Group List. Then you create 2 channels, one with 123 as the transmit talk group, one with 456 as your transmit talk group. You assign the "combined" Receive Group to both channels.

In my radio(s), I have ALL my normal Brandmeister talk groups in one massive Receive Group (I call it "BM All"). I assign this receive group to all my hotspot channels. That way, whatever talk group I may have active on my hotspot (out of my normal selection), and whatever channel I have my radio set to, I'll hear what transmits out of my hotspot. I just have to remember to change to the channel of the talk group I want to respond to.
Interesting. Does this mean that the talk groups in your “BM ALL” list are all Made static in your Brandmeister dashboard setting?

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