How high to mount antenna......

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Larry
Posts: 160
Joined: Fri Mar 01, 2002 4:00 pm

How high to mount antenna......

Post by Larry »

How high should I need to mount an antenna to get 6 to 10 miles from a repeater antenna operating at 50 watts 460Mhz?

Previously I was using a 3db gain mag mount mobile antenna mounted on a 2ft sqaure steel plate and was getting approx 2 miles in simplex mode from radio to radio at 40 watts... I just upgraded to a Antenex UHF fiberglass base station 3 db gain antenna and purchased a /\/\ GR1225 repeater with duplexer.

The property is a office condo suite... the office is located on the second floor of a 3 story woodframe building... The site terrain height is about 20ft below the average terrain. The area has dense construction of single family homes...

Anybody know how to find lease space on a tower? I tried several local radio shops and they didn't do any antenna towers...
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alex
Administrator
Posts: 5762
Joined: Mon Sep 03, 2001 4:00 pm

Post by alex »

What does your license say for a location. If you are operating a licensed repeater on a certain frequency, the information regarding where that antenna is located is on your license.

You might have to change that in order to relocate your antenna, espically to a tower.

-Alex
Nand
Posts: 1691
Joined: Wed Oct 31, 2001 4:00 pm

Post by Nand »

There are many factors that play a role in RF propagation. Height above everything else is most important and should be about 100 to150 feet in your case and that doesn’t give you much of a margin. I higher gain antenna will help depending on terrain.

If you can’t see any towers in your area, perhaps try for a water tower or tall hospital building. Or how about a church steeple? Buildings may not be very high, but they have the advantage of not needing a lot of expensive low loss feed line.

Nand.
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