11m & 2m Antenna Spacing

[Slim Pickins]

I currently have my 11m antenna hard mounted to the middle of the roof on my extended cab F150. I am planning on installing a 2m set-up in my truck as well. How far apart should the 2 antennas be? I have a base loaded hybrid cb antenna (about 65" high) and my 2m antenna is a NMO mount (about 48" high). How much would they affect each other if they were both on the roof? Or, should I just put the 2m antenna on a front fender mount, which i already have? Would having the 2 antennas on the roof cause direcionality in the antenna I am using like a beam? I don't really want that if I can avoid it.

Thanks for any input
Slim

[BushHog]

I use to run mine maybe 6" apart, 11m on a tri mag with 2m in front of it on its on single mag mount. Never had a problem.

[hilltop 439]

Hello Slim Pickins .
I to am running a 11 meter antenna and a 2 meter antenna on my GMC Yukon. I do not notice any directional effects from having the two antennas on the roof. But it is a good point i never thought about . I suppose it is possible by all means. I do have problems with feedback when transmitting at times when the two radios are on . It dosn't matter whitch radio i key up one seems to effect the other. The antennas are around 4 feet apart this could be the problem. Do you have any issues of this nature with your setup as it is now ?

[MDYoungblood]

Hey Slim Pickins,
I had my business antenna (Antenna Specialist 150mhz) and cb antenna (Antenna Specialist Big Momma) on the roof of my pickup. They were both base loaded and mounted 8"s apart. This was recommended by Antenna Specialist customer service. You don't have to worry about directivity because they are so close together. The hard part is adjusting swr, you will have to do them both several times, each time you move one it knocks the other out.

3's

Greg

['Doc]

Since they aren't on the same band, the two antennas shouldn't have much affect on each other. The further you can get them apart the less that 'affect' will be, but something else to consider is will they be close enough to touch if there's more than average 'shaking' of the vehicle? I have more than two on my car, maybe 1.5 to 2 feet apart, all three are 5/8w 2 meter antennas. I've noticed that they will whip around a bit at times and I've heard them touch (I think that's the sound?). So far that hasn't been a problem, but I also don't transmit after going under things (when that touching thingy happens). Just something to keep in mind.
- 'Doc

[Slim Pickins]

Thanks for the replies everyone. Now I just need to decide if I want to pull down the head liner again or take the easy way out and go with the fender mount.

['Doc]

Slim,
After you pull that headliner down enough times and you get really good at it, you wanna do mine too??
- 'Doc

[Slim Pickins]

Sure thing Doc. Bring her up to Nov Scotia we"ll give er a go.

[SILLY RABBIT]

Well i can add dont run a big amp on 11m with a 2m radio in the car.Im on my third 2m.

[Slim Pickins]

Ok, I got lazy and installed the 2m antenna with the fender mount. Just didn't want to take down the head liner again.

Slim

[binrat]

On my ext cab GMC, I had problems between the both at 2'. So the 2 metre is on the front fender at the windsheild and the wilson is about where the interior light is. I run 65 watts on the 2 metre and it still effects the 11 metre when I'm doing APRS. Nothing for voice, unless I run too much power on 11 metres.