Tx power of EDACS vs. Smartnet

[kyparamedic]

I have noticed that the neighboring smartnet system tends to have better range than our EDACS system. I looked it up and found that their transmitter sites operate at 150w and mobiles at 35w. Ours are 100w and 25wy. Why do EDACS 800MHz systems/products operate at lower wattage?

[KS4VT]

Originally Posted by kyparamedic

I have noticed that the neighboring smartnet system tends to have better range than our EDACS system. I looked it up and found that their transmitter sites operate at 150w and mobiles at 35w. Ours are 100w and 25wy. Why do EDACS 800MHz systems/products operate at lower wattage?

It has nothing to do with the technology at all. There are many other factors such as NPSPAC (which has ERP & coverage limitations) vs non-NPSPAC that does not have any. Your system may have a closer co-channel user and the coordinator made the requiremect, or it could be tower site placement and antenna patterns.

The older Motorola were also built with MSF5000'S that 150watt decks and the newer systems use Quantars that are 100 watt stations so not all Moto systems have 150 watt repeaters.

[zz0468]

To carry KS4VT's comments further, if it's a simulcast system, the power requirements may be even lower. I've deigned simulcast systems where one or more sites use 10 watts or less to tightly controlled antenna patters to provide the desired coverage. In a case like that, it's quite important to put a precise signal level into a precisely defined area. The brand name has nothing to do with it. I've done that with both EDACS and Motorola systems.

[kyparamedic]

On the mobiles though, it looks like the M/A-COM ones have a maximum output of 25w while the Motorola ones are 35w. Am I missing something on this?
BTW, we operate a multi-cast system.

[KS4VT]

25 or 35 doesn't really matter as the systems were probably designed for low power portables. The 10 watt difference doesn't really make it or break it, especially when you can cake up the difference with antenna gain.

We set our mobiles to low power (10 to 15 watts) even though they are capable of 35 watts.

[zz0468]

On the system I maintain, we're power limited to 5 watts ERP on the mobiles in some areas. I suspect the choice between 25 and 35 watts out on the mobiles was the result of a cost-benefit analysis done by the manufacturers. Or maybe Motorola was able to give themselves a discount on the higher power device used in the PA, who knows... The difference is completely insignificant in the real world.

[kyparamedic]

Ok, thanks for the explanation. Why does VHF tend to operate at the highest power of all yet has better range to begin with (generally)? I can use a VHF portable from the next county over where I work part-time and get out on low power from inside a building. I can't do the same thing on 800 in the reverse situation. Sorry if these are dumb questions. I've learned a lot though reading this board.

[KS4VT]

Can't really answer the question because there are too many variables to include site placement, any nearby VHF satellite receivers that your not aware of, is the 800 system a NPSPAC system that limit's it coverage outside its jurustictional boundaries by local rules.

Most portables are programmed to high power just by default because there is no telling were it may be utilized, so it is done that way on purpose.

On the other hand you may find places that the 800 works and the VHF doesn't. You just may have been in that location yet.