Multiple antennas on home - question on adding GMRS base antenna or other antenna(s)

[N-L-M]

Currently have CB antenna (attached to side of home) and multi-band scanner monitoring antenna (mounted on chimney) on the one side of the home about 20' apart. Thinking of adding a GMRS antenna (J Pole) to the home (If I decide to move forward getting a GMRS license and other equipment) connected with LMR 400 cable.

My question is adding a GMRS antenna or any other antenna (possibly digital tv).

- Looking for advice of placement location in relation to other antennas?

- Minimum distance apart?

- Other things I want to consider?

- Thought about putting an attic antenna for GMRS or the Digital TV. I am sure there are downsides to this. Years ago I had a CB antenna in the attic and it worked pretty well - before I was able to get the outside installed.

Thank you

 

[MTS2000des]

The biggest key is vertical separation of at least 10-20 feet for transmitting antennas to prevent interaction. The challenging one will be keeping your DTV receiver happy from GMRS. Most DTV is UHF and most DTV receivers are trash cans for keeping nearby UHF LMR out. You'll want to keep your DTV antenna as far as vertically away from your GMRS. The CB antenna should not bother it as much, but then again, most DTV front ends are like Bowelturds as far as overload rejection.

I use an indoor amplified antenna from Antennas Direct (I'm close to pretty much all ATL DTV) and it gets bothered when I key up an 800MHz or UHF portable in the same room. Knocks out reception on my Samsung 50" OLED.

 

[N-L-M]

The biggest key is vertical separation of at least 10-20 feet for transmitting antennas to prevent interaction. The challenging one will be keeping your DTV receiver happy from GMRS. Most DTV is UHF and most DTV receivers are trash cans for keeping nearby UHF LMR out. You'll want to keep your DTV antenna as far as vertically away from your GMRS. The CB antenna should not bother it as much, but then again, most DTV front ends are like Bowelturds as far as overload rejection.

If only one antenna is being used at a time (no other devices are on) - does the vertical separation still matter?

 

[mmckenna]

If only one antenna is being used at a time (no other devices are on) - does the vertical separation still matter?

Yes.

Antennas in close proximity can impact the radiation patterns. In other words, two or more antennas close together can make one or more of the a bit directional.

Other issue is that the RF energy from the transmitting antenna can get into nearby antennas. That RF will find its way down the coax to the receiver. Too much RF in the receiver will temporarily deafen it. If the antennas are too closely spaced and/or there's a lot of RF power involved, it can physically damage the receiver.

I think the 20' advice given above is a good place to start.

As for installing in attics, that can work OK, but just make sure there isn't any metal component to your roofing materials or any insulation (foil backing vapor barrier).

 

[N-L-M]

As for installing in attics, that can work OK, but just make sure there isn't any metal component to your roofing materials or any insulation (foil backing vapor barrier).

This house has aluminum siding- so I guess that would be a problem.

 

[celestis]

The biggest key is vertical separation of at least 10-20 feet for transmitting antennas to prevent interaction. The challenging one will be keeping your DTV receiver happy from GMRS. Most DTV is UHF and most DTV receivers are trash cans for keeping nearby UHF LMR out. You'll want to keep your DTV antenna as far as vertically away from your GMRS. The CB antenna should not bother it as much, but then again, most DTV front ends are like Bowelturds as far as overload rejection.

I use an indoor amplified antenna from Antennas Direct (I'm close to pretty much all ATL DTV) and it gets bothered when I key up an 800MHz or UHF portable in the same room. Knocks out reception on my Samsung 50" OLED.

My HDHomerun box's tuner got damaged by 4 watts out of an XTS3000

So lame for such a neat little box