Batboard

My buddy is putting a nextel repeater in his fire station so they can have service inside their building. His question to me was where to put the actual repeater unit. They have a long run I think about 200'. Should it be places closer to the outside antenna or the inside antenna?

Spatch713 wrote:My buddy is putting a nextel repeater in his fire station so they can have service inside their building. His question to me was where to put the actual repeater unit. They have a long run I think about 200'. Should it be places closer to the outside antenna or the inside antenna?

You need to have 20 dB or more isolation between inside and out than you have gain in the amp. example: You have a 50 dB gain BDA. You need 70 dB or more of isolation of the signals outside versus the same signals received inside the building to prevent the amps from oscillating. The location of the amp doesn't matter as long as you maintain the isolation. Use Heliax or other rigid coax for the donor antenna, not RG8. Where is your "long run"? To the donor antenna or to your inside distribution?

Just to say it..... Nextel goes nuts when BDA's go in without coordination and they screw up a site due to the thing running WFO and eating up the receivers. I would suggest coordinating with them just as a CYA for your bud. At the very least, the TX ERP from the donor yagi on the BDA should not exceed the max ERP from a portable from the same location. The whole concept of the BDA is to negate the attenuation caused by the building and not to amplify signals to higher than normal levels at either end.

Dave

OK, I will pass this on to my buddy. The thing is going in a 5 story commericial building at a power plant. I am pretty sure they have radio guys there to help them but my buddy is speculating on how they might do this. I actully find it kinda of interesting as well.

Just an FYI, it is a violation of Part 90 rules to install a BDA to amplify signals that you are not licensed to. Your radio guys should know this
and it would be best to call NEXTEL corporate to arrange for them to design and put it in.

http://a257.g.akamaitech.net/7/257/2422 ... 90.219.htm

Thats their problem - im just asking the question because I though it was a good question and I havent got a clue as to what the answer is. I'll pass it on but im sure they have already taken care of this since its been there a long time and its in a nuclear power plant.