groundplane question

[zues2054]

Grou

Thanks for the response..
Your information confirms what I've read online. The helicopter is in Experimental Exhibition Category which allows me to work on it with out an A&P license, that being said I'm working closely with an A&P but I wanted some information from people that work with RF regularly to pull many ideas together.

 

[arkieguide]

antenna mount

So if I put a piece of metal - 6" x 6" - on top of my roll bar which is 2" + or _ higher than my truck cab.It would work as decent ground plane ? i have mounted antennas on the side rails of a truck, each side of the roll bar, on the tool box,etc. I want to get more height for the antenna and go with a 3 or 4' antenna. I am told if I put a plate out from the roll bar enough to mount the antenna center of cab but a couple inch's higher, I would not get good results ? `Thanks, you folks have been great to help me.

 

[cmdrwill]

A "decent ground plane" has to be one quarter wave in all directions.

A mounting tab off of the roll bar will not provide a ground plane.

So at VHF you need 38 to 40 inches in diameter. At UHF 13 inches. The " 6" x 6" " ground plane will only work for antennas higher than 900 mhz.

Your cab roof will provide more ground plane for your antenna.
But you mention 3 or 4 foot antenna, that seems to be for a CB, 27 mhz. If you are using CB, then a NMO27 would work much better.