Newbie Repeater Questions

[contrak10]

I’m looking into buying a repeater for school I work at. It’s most likely going to be a GR1225 UHF with an Antennx antenna. However my problem is that we have 4 frequency pairs that need to have a repeater to hear throughout the building. The repeater will be at 25 watts. My two questions are; is it possible to have the repeater function on 4 frequencies (4 channels) using only 1 repeater, or do I have to buy three more repeaters? Also, is 25 watts too little or too much? The school has four buildings connected to each other; the newest building built in 2000 is composed of all steel, has three floors and is about 70 yards long. I was hoping to use the Antenex Phantom antenna or something small, any suggestions?

Thanks

[KG6EAQ]

is it possible to have the repeater function on 4 frequencies (4 channels) using only 1 repeater, or do I have to buy three more repeaters?

Three additional repeaters. The GR1225's will only do one pair at a time. I assume each of these four frequencies are licensed for repeater operation at your location?

Also, is 25 watts too little or too much? The school has four buildings connected to each other; the newest building built in 2000 is composed of all steel, has three floors and is about 70 yards long. I was hoping to use the Antenex Phantom antenna or something small, any suggestions?

Probably too much, but impossible to say without a site survey. Most industrial institutions do fine with 5 and 10 watt repeaters. The wattage of the repeater will mean sh!t if you are using a Phantom antenna, where are you going to install it? On top of a filing cabinet? I know antennex says they can be used for stationary installs but I doubt you NEED to restrict yourself to that model. You could get a much higher gain antenna and give you a better signal. The steel building won't effect the repeater as much as it will hurt the portables. They will probably hear the repeater but their signal won't make it back in.

You also need to consider how you will mount both antennas or if you will use a duplexer.

BEST ADVICE = Contact a local two way radio professional to survey the location in person and make a proposal up.

[contrak10]

A small antenna is needed because the buildings unique architecture makes it impossible to mount an antenna noticeable antenna on the roof. It would be best to stick a small antenna on the roof or an indoor antenna. Any suggestions? Is there any repeater that will repeat more then one pair of frequencies? Yes, we do have a temporary license active, until we receive our own pairs. The license is good for 25 watts

[doi]

a repeater with an indoor antenna... hmmm.... sounds interesting.....

really if you're going to put an indoor antenna on the repeater you should better think twice if you really need that repeater.

anyway - for the funny part - it would be nice to see a four channel repeater all together with rack, splitters, combiners, duplexers etc. and all of them connected to a mag mount antenna on a metal cabinet.

just my 2 cents... maybe I'm wrong

[Will]

Mount the antenna on the roof??? worst thing to do for a repeater that needs to have coverage INSIDE the building.

Several small 1/4 wave antennas on a feeder inside the building may be what you need. Usally mounted upside down from the ceiling in the middle of the building and branches if needed.

[KG6EAQ]

Mount the antenna on the roof??? worst thing to do for a repeater that needs to have coverage INSIDE the building.

Several small 1/4 wave antennas on a feeder inside the building may be what you need. Usally mounted upside down from the ceiling in the middle of the building and branches if needed.

Com'on Will, don't you think he should do like Santa Anita and mount the 1/4 antenna 75ft up on a pole for local comm's :p

[Will]

Chatsworth Robert, do you mean the race track or the shoping mall?

[KG6EAQ]

Chatsworth Robert, do you mean the race track or the shoping mall?

The race track that you fixed my friend If you get a chance PM me tomm about how the picnic went, work won't let me take off to go.

[Will]

The "race track" now has ComTelco unity gain antennas on the repeaters. Much better coverage in the local facility and a very big reduction in co-channel interference from other stations. They used to have Stationmasters, the 5db (7.9dbi) gain antennas mounted much higher, and got severe co-chan and poor local coverage.

This is a UHF splinter 2 watt repeater system, accually there are 5 repeaters 3 in one area and two others, each has its own mast & antenna, and several simplex systems. This is to minimise the failure as the only common thing is the AC power.

Comtelco BS450U Unity gain, 2.9dbi, with a fat 75 degree pattern.
they have two halfwave copper elements inside the 1.35"dia fiberglass sleeve, with a heavy wall epoxy coated aluminum mounting sleeve.


http://www.comtelco.com

[doi]

just my 2 cents... maybe I'm wrong

and so I was...