Base Install Antenna cable, etc.

elkbow · Post by **elkbow** » Tue Sep 24, 2002 9:26 pm

Okay....I want to install a UHF base in the house, just something like a Maxtrac or GM300, etc. What do I use for cable type and what do you recommend for antenna? For cable do I use RG-8U, Davis RF Bury-Flex, 9913??????? Setup will only push approx. 40 watts.

fire-medic8104 · Post by **fire-medic8104** » Thu Dec 05, 2002 8:13 pm

sorry I meant to ask a few weeks ago when I first saw this. How far are you from the repeater, if on a repeater channel? If simplex, what range are you looking for? I am 6 blocks from my personal repeater, so I just use a Maxtrac with a magmount and a 1/4 wave antenna at 34 watts. On simplex I get about a 4 mi range. If you have access to mount it outside, you could probably use a fiberglass omni-directional using house brackets and double the range. I personally like LMR-400 which is 1/2" diameter. Be sure to put a polyphaser inside preferably near your radio, ground the polyphaser to a ground inside the house(to a ground in a outlet would be okay), and use a RG-58 jumper from the polyphaser to the radio. Try to keep the jumper shorter than 6'. Its all about what you want to do.

elkbow · Post by **elkbow** » Sat Dec 07, 2002 1:02 pm

Well I would mostly use on simplex, but the repeater is line of sight at about 12 miles, could hit it with .5 watt without a problem. The cable run would be less than 50 feet, been told by others if the run was more than about 40 feet to go with LMR600, otherwise 400 would be okay. I am going to put up a Comtelco XL series antenna.

fire-medic8104 · Post by **fire-medic8104** » Sat Dec 07, 2002 2:02 pm

I use LMR400 on alot of base stations. I have never personally used 600 so I couldn't say on that. I have used LMR400 on runs of up to 150' with no problems. I guess it's just a matter of preference. Just make sure whatever you use get some good vapor wrap and seal connectors and all entries. Good luck, it should go ok.

Post by **vcaruso** » Sat Dec 07, 2002 3:45 pm

I agree with Fire-medic, LMR 400 works great, and you will really get some great coverage with the Comtelco antenna

The only thing I would do diffrent is run a ground from the Polyphaser to a service or cold water ground with a solid 10 or 8 AWG conductor.

raz · Post by **raz** » Tue Jan 07, 2003 3:55 pm

Pardon my ignorance , but what is a polyphaser please ?

fire-medic8104 · Post by **fire-medic8104** » Tue Jan 07, 2003 4:24 pm

I forgot to mention the polyphaser. Basically, a polyphaser is a surge protector that goes in-line with the coax. Most polyphasers are a little silver box with connectors on both ends, either N female or PL-259 female. It has a tang with a small hole in it. Use a bolt to connect a ground wire to it and run it to a ground, like vcaruso said, a 8-10 solid awg conductor, to a service ground for the electrical system or cold water ground. A polyphaser is cheap insurance for lightning protection.

JAYMZ · Post by **JAYMZ** » Tue Jan 07, 2003 5:58 pm

I agree with firemedic and vcaruso in using some sort of lightening protection. Otherwise the picture below could be the inside of your radio.

That was what was left of a 33 mhz base station at my job. The radio WAS used to talk to the county Dept of Public Works.

We received a direct hit of lightening at 0403 in the morning one day this past September. That radio was one of several casualties including the nerves of my partner and I.....

fire-medic8104 · Post by **fire-medic8104** » Tue Jan 07, 2003 6:05 pm

WOW! I have replaced connectors that have been hit by lightning but never anything that was burned in two. Was this inside or outside the building? Did it have a polyphaser to protect it, or was it before the polyphaser?

JAYMZ · Post by **JAYMZ** » Tue Jan 07, 2003 6:22 pm

That came off the base of the antenna. The antenna was on the northwest corner of the tower (right between our microwave links to our main towers...whew...). The antenna was still there but the feed line was gone...

That piece shown there was cut off from right next to the building. The center conductor is gone....still haven't found it....probably never will.

The radio was repaired and put back in service a week later. I still have the connector as a souvenir from that night. No lightening protection that I can recall on that radio. Everything else in the back room is grounded. We still lost our router for the network...the GPS Netclock...a moniter....the phone at my console went nuts.....and a few other minor things.

Charlie and I were still shaking when we left at 8 am that day. Luckily I had just shut down my laptop from programming some channels in my Astro Saber about 5 minutes before we got hit.

Base Install Antenna cable, etc.

Base Install Antenna cable, etc.

polyphaser ?