Larsen NMO-27 roof mount too near to luggage rack?

[Sonicadventure]

Hi have a Volvo wagon with no sunroof. Large flat roof creates nice ground plane.

Planning to mount a base-loaded Larsen NMO-27 dead center in the roof's sheet metal as I have done in the past on a prior Volvo wagon. This wagon has a tube steel luggage rack that is mounted on crossbars that will sit just behind the antenna.

My question is, how much will the proximity of the steel luggage rack interfere with a baseloaded whip? What if the rack is 1" inch away from the base load, 5" away from the base load, any potential for difference?

While I do plan on using the CB for awhile, there is a chance I might want to change out the CB at some point in the future for a small 2M/70Cm mobile unit and swap out the Larsen for a suitable antenna. Would signal interference from proximity to the luggage rack be more or less pronounced on those frequencies? I'm trying to avoid having to drill multiple holes in my roof.

 

[mmckenna]

I remember your original install a few years back.

For CB, it should not be an issue.

For VHF, probably not an issue unless the rack is really tall. For UHF, may be more of an issue.

Keep the mount a few inches in front of the rack and you'll be OK.

 

[cmdrwill]

If you use a quality NMO antenna mount and cable, you can use a CB or VHF by changing the antenna.