Building doc for OpenGD77 way of doing Talkgroups etc

ve2ugo
Posts: 46
Joined: Sat Nov 16, 2019 5:28 pm
Location: Quebec, Canada

Re: Building doc for OpenGD77 way of doing Talkgroups etc

Post by ve2ugo » Sun Sep 05, 2021 5:42 am

I posted here since it is here that the beginning of a conversation on the topic "roaming" had started.

Personally, I would like a little research more serious to be done on the possibility of adding the "roaming" function to the GD77 which according to my perspective is easier than some think to implement and that the hardware of the gd77 would allow to do ...

For me it is this function which would be a very big step forward !!!

In North America, (Canada, USA), DMR Marc(DMR +, DMRQ) and Brandmeister works very well when roaming ...
It is also much more convenient and safe to use this function on the move.
He just does the research of the strongest RSSI in the zone where you are and among the list of RPTR, that you created, that he must check ...

Allowing the radio to change RPTR automatically when moving to choose the most powerful one is an important function in my opinion. Especially with a portable at low power, we are often limited on the move ...

I don't see why Australia or other places in the world that this system would be more complicated and less practical than others ...
I understand that there are places that are flatter on earth and less hilly than others making communications more easy, but the feature compares to a cell phone and to improve safety. Distance, interference or a building for example is a condition where roaming is also useful.
With my Anytone, I can, for example, travel 600km and follow the same conversation by changing automatically from RPTR without ever touching the radio and keeping my eyes on the road ...

The Anytone 878 has only one receiver as well and roaming like many Motorola and Hytera.

I think this is an important feature to consider, especially since it looks like you still have room to add code with the latest Beta I saw coming up!

I think this function is worth considering with more importance and great interest!

Thanks for the great job you have already done!

kt4lh
Posts: 272
Joined: Sun Jan 12, 2020 4:27 am

Re: Building doc for OpenGD77 way of doing Talkgroups etc

Post by kt4lh » Sun Sep 05, 2021 4:36 pm

Yes, Roaming on a lot of radios is literally just the radio kerchunking the repeater in a specific way and seeing if it hears anything back. So the typical setup is if roaming is on, it'll just ping the current channel every N seconds and if it doesn't get an appropriate signal back, it starts basically scanning and pinging each until it gets a response at which time it stops.

I do not know the technical aspects of it, such as what the radio is actually doing. I assume it uses the current timeslot and color code, but is it poking a particular talkgroup? That I don't know. But afaik it's not particular complicated, just looks for a signal, if not, keeps looking.

That all said, I've heard multiple times that most repeater systems do not like roaming as it means every radio in the area would be pinging it all the time. I don't know if that causes any interference with getting into the repeater or just keeps the repeater busy or what. If the repeater is in active use then any radio that's roaming should of course not be pinging because it would detect the signal before attempting it.

EDIT: Didn't realize this was thread necropsy; this was already responded to months ago. I do think roaming would just work on GD77 however since it is actually a pretty simple mechanism.

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