Evaluating repeaters

[bryanm67]

Hi everyone,

I am on the security team of a church in Central Arkansas. We have two buildings that are roughly 300 - 400 yards apart (door to door). The distance for transmissions can often be further as a security team member could be transmitting from anywhere in the building.

As a result, we are having alot of difficulty getting our radio signals to get from one building to another with a clear signal. At best, we have a fuzzy signal and there is alot of "please repeat that transmission". I suspect that the problem is not merely distance, but the number of walls that the transmission has to go through, and the amount of electrical interference (our church has a sound booth, video booth, electric guitars, etc.)

Currently we have no base radios. All of our radios are Motorola radios (the portable clip-ons). We are looking at the possibility of purchasing a repeater. But we do not have any experience in buying or evaluating a repeater. Any pointers or suggestions would be appreciated.

Thanks!

 

[Project25_MASTR]

The used frequencies and radio models is a good place to start. The licensing information is another good place to look.


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[slicerwizard]

OP probably only needs passive repeater setups on each building's roof.

 

[mmckenna]

Currently we have no base radios. All of our radios are Motorola radios (the portable clip-ons). We are looking at the possibility of purchasing a repeater. But we do not have any experience in buying or evaluating a repeater. Any pointers or suggestions would be appreciated.

Thanks!

Is the church currently in possession of a valid FCC license for any frequencies?
-Without a license you can't legally put up a repeater for anything short of WiFi radios.

Are you using consumer grade FRS/GMRS radios?
-Repeaters are not allowed on FRS. On GMRS they are, but each person on the team will need a valid GMRS license from the FCC. There is no exception to this.
-Most FRS/GMRS radios are not capable of operating through repeaters anyway.

Over 400 yards you shouldn't have too many issues with good UHF radios on simplex (radio to radio). I suspect your issues are related to low quality/low power consumer grade radios.

Before spending money on frequency coordination, licensing, repeater, antennas, and new radios, you need to try a few things:
1. Borrow/Rent some commercial/professional quality radios that work without a repeater, first. Give those a try and see if they'll provide the coverage you need. This small investment could save you a LOT of money.
2. If those don't work, I'd strongly suggest talking with a local radio dealer. They'll have the knowledge, tools and background to help you out.
-before you talk to them, though, make sure you have a clear definition of what you are expecting out of your radios. This needs to be realistic expectations, not a "wish" list.
-Also, make sure you've decided on a budget. If you walk into this without a budget you run the risk of getting taken advantage of. I can tell you that Spending $2000 on a repeater system could happen really easy. Repeater capable radios could be $150 - $200 each.
-Avoid the temptation of the cheap Chinese radios.

Feel free to ask questions. This can get a little complicated, so it'll take a while to figure out.
Even as a church, GMRS use is not legal without a license

If you have WiFi network access through your facility, it might be worth checking into WiFi radios. There are a couple of manufacturers that make them. Might make more budget sense to beef up WiFi coverage for everyone and just piggy back your two way radio use on that system. Might actually be a bit cheaper in the long run.

 

[slicerwizard]

Then WiFi coverage would have to be extended to cover the entire outdoors of the property, no? Security has to have coverage in the parking lot(s) as well as the rest of the grounds. Even then, the radios will die if they do something as minor as cross the street...

 

[gewecke]

The wise thing to do would be hand out a bunch of Murs radios with 1/2 wave antennas to their minions and call it a day. 73, n9zas

 

[RFI-EMI-GUY]

(snip)

Currently we have no base radios. All of our radios are Motorola radios (the portable clip-ons). We are looking at the possibility of purchasing a repeater. But we do not have any experience in buying or evaluating a repeater. Any pointers or suggestions would be appreciated.

Thanks!

It sounds like a low power 2 or 5 Watt repeater and exterior antenna may be the way to go to improve in building coverage between the sites. I suggest you plan to install the repeater on the building with the largest footprint or at some building central to the coverage problem.

Are these the Motorola CLP10x0 series? If they are the CLP1010 then they are a single channel so once programmed for a repeater can only be used on the repeater, no talk around. The other models are multi channel.

The CLP series has a limited number of standard repeater offset frequencies. Not sure why Motorola made these so very restrictive.

The CLP radios are preprogrammed with certain Industrial/Business frequencies which you are limited to. Not sure if dealers can expand these choices.

Motorola sells a CLP compatible repeater (The RPX) that in my opinion is more suitable for portable short term use. I would not want to be the guinea pig on this model.

Ritron's popular low power Liberty repeaters are compatible with the CLP series. You can download for free Motorola CLP series CPS for programming the repeater pair into your radios. You will need to modify your FCC license for the repeater pair. The radio dealer will have to program the repeater and tune the duplexer.

And yes, you might be simply better off with clunky 4watt commercial radios and 6 inch whip antennas.

 

[RFI-EMI-GUY]

OP probably only needs passive repeater setups on each building's roof.

I believe they are using Motorola CLP10x0 "clip on" series. Very low effective power and effective sensitivity.

Passive systems when they work, work in places like vaults and with higher power repeater systems. Any passive system has additional free space loss that must be accounted for.

 

[gewecke]

Hmm... where did Bryan go? 73, n9zas

 

[RFI-EMI-GUY]

Hmm... where did Bryan go? 73, n9zas

Probably looking for that pesky FCC license the Motorola dealer told him "not to worry about".

 

[gewecke]

I think you mighr be right. 73, n9zas