Batboard

I vaguely remember that there is a Federal guideline for the maximum number of users per channel. Does anyone have a reference ?
I suspect that it might apply to trunked systems rather than conventional but I could do with numbers for both types.
If there isn't a definitive answer, does anyone have a rule of thumb?

Thanks

Look in Sub-part L (T band).

I think your research will provide that there is a minimum not max for channel loading on a trunked system.

Jim

judoka wrote:I vaguely remember that there is a Federal guideline for the maximum number of users per channel. Does anyone have a reference ?
I suspect that it might apply to trunked systems rather than conventional but I could do with numbers for both types.
If there isn't a definitive answer, does anyone have a rule of thumb?

Thanks

I've been told up here in the Great White North by Industry Canada (our FCC) that for trunked systems, they consider 75 users per voice repeater to be a guideline. So, if you have 300 radios, they'll allow you to license up to 5 repeater pairs (1 control, 4 voice). In reality, how you set up your fleet mapping & total number of actual user groups is far more important...you can have 1000 users, but if they're all on the same talkgroup, you'll only need a single repeater since only one guy can talk at any one time. Set up 300 users on 40 different talkgroups, then you'll run into problems with a busy system.

For conventional, those things don't really apply, however they require you to have at least 25 field radios before they'll grant you a repeater license. Again, it's a guideline & exceptions can occur.

Todd

Thanks, that is exactly what I was looking for.
I am really trying to find out how annoyed the conventional users get when there are too many on the channel. On a trunked system with 300 users in a single talk-group, I only need one traffic channel. The system can tell me how many times a user is busied out immediately because there somebody is already on the talk-group (call collisions).
On a conventional system it just happens, people figure it out and nobody measures how long people wait until they get a chance to talk.
Dispatch controlled channels have better capacity because somebody is organising things. I have been trying to play with some Erland calculators but they don't like it when you set 1 circuit and try to find out how much load will cause a given waiting time.
With trunking and many talk-groups the erlang models start to work if you can figure out how to guess the busy hour traffic.