GR300 repeater range,site? input, help needed

[hfd921]

Have a question for the radio Gerus

We currently operate a GR300 uhf repeater it is 60 feet off the ground operating at 25 watts, yes I know it’s a small tower. The range isn’t really to good, we primarily use portables and we are mostly is our vehicles. It’s used for talk around operations nothing major, but we do need good communications. To describe the area it is urban. The antenna is up 60 feet but it appears everything around it is taller than the tower. The school gym and stadium are taller and the surrounding pine trees are a tad taller.
I’m guessing this is killing the range because of obstruction?

Now we located a site 5 miles way, the site is to compare is approximately 13 stories tall, definitely taller.

What type of range should we get with the increased height?

Just curious, will this solve all the issues or just stay where we are at?

[escomm]

You need a coverage plot to determine what potential improvements would be realized by relocating the site. Things such as feedline and antenna selection will impact coverage as well. There is no simple answer to your question, but generally speaking, there's no replacement for elevation.

[Bill_G]

Either PM me the two sites lat / long, along with your email addy. I'll produce a simple tri-color plot for both (green good, red bad, yellow that 12db space between green and red where it can get dicey). I'll send you a jpg to print, and a kmz so you can look at it on the Google Earth. Zero dollar charge since you're saving lives on a tight budget. You'll get your answer, and then you can pound your board of supv to cough up a few bucks to the local vendor.

Needed info - site lat long, ant elevation (approx), band of operation
Nice info but I can make a guess if you don't know - ant gain, power out of station into filters/duplexers/combiners or power out of filters to ant line, type of line and approx length, any other known losses or impairments.

[motorola_otaku]

Yeah, a lot of blanks here that need filling in:
-Make/model of antenna?
-Type of coax/feed line?
-Make/model of duplexer? Who tuned it, and what did they use?
-Length and type of cable from the radios to the duplexer?

Generally speaking a GR-series repeater is not hard to get up and working right, but you need the right tools to do it. The duplexer needs to be tuned with a service monitor or spec-an/tracking generator combo, then the whole system needs to be tested for power out, de-sense, and squelch open point. Don't use RG58 cable for your radio-to-duplexer cables, use RG142 or RG400, and try to keep them under 3 feet in length.
Don't use braided coax anywhere between the duplexer and antenna if at all possible. LDF4-50A or FSJ4-50B Heliax is more than adequate for a 60' antenna run. Also don't use adapters (or PL-259s) anywhere in any of your cable runs.