Experience with LTR Loading?

[Birken Vogt]

We have recently installed an LTR system, works way beyond anyone's expectation, and the customers love it. Using LT-4200 controllers and 3 repeaters for now. The boss has several more large-ish customers that may be coming on board. He is itching to pull the trigger on two more FB8's. I am thinking this may be overkill.

What I am after is some specific numbers as to what customers typically find acceptable system performance vs loading. I don't really know how to interpret the numbers the system gives me either. There are the loading stats for each repeater. But I suspect the information that I really need to keep my eye on is the trunked full percentages and the system loading % that appears in the monitor screen. But I don't know what that one is supposed to mean. I assume it is the percent of the available airtime that is being used but how far back in time does it go? It seems to change fairly rapidly, sometimes it is near zero and I have seen it up around 15% during the busy parts of they day.

Of course any other rules of thumb regarding customers per channel or trigger points for getting new channels would be nice. We are totally new to this here but dang, wish we had thought of this years ago, we'd all be rich by now!

Birken

[wavetar]

Trunking systems in general are nice, allowing lots of customers to share a few repeaters.

A rule of thumb the FCC/DOC use is "100 users per voice repeater" before considering the system loaded to capacity. In reality, this is a very arbitrary number. It more depends on numbers of distinct talkgroups in the system, not individual users. A company can have 500 radios, but if everyone's on a single talkgroup, the loading will be considerably less than having 10 companies of 50 radios...each company having their own talkgroup. On a 3 repeater system, 10 busy companies could easily load the system to the point of unacceptable delays.

I'm not familiar with the stats given within your particular controllers...in the Motorola world, you can see number of system busies within any 15 minute period, and the average time before access is granted to a radio in the busy queue. A few are ok, especially if they are short. If you're seeing a few dozen busies all the time, then it's time to start thinking about adding another repeater.

Todd

[Jim202]

Loading is somewhat like saying how much wind is blowing. It all depends on how much airtime each user is taking. If you have a taxi cab user on your system, they will probably run the air time right off the scale.

At the other end might be a print shop that uses the radio for their delivery truck. They normally wouldn't use much air time at all. You have to kind of ballance the users with how much air time they all will use diring the day. Match which channels you place everybody on with the amount of air time they will use.

Don't forget to factor in the weather. Some busineses will use more air time when it gets hot or cold than others. Like plumbers in the winter, air conditioning in the summer.

Jim

We have recently installed an LTR system, works way beyond anyone's expectation, and the customers love it. Using LT-4200 controllers and 3 repeaters for now. The boss has several more large-ish customers that may be coming on board. He is itching to pull the trigger on two more FB8's. I am thinking this may be overkill.

Birken