Newbie needs help with antenna mounting

[FFRNDAN]

I'm having a headache rack built for my new truck, and the guy is throwing on a couple tabs for mounting antennas. One will be a dual band VHF/UHF, and the other a CB. Since NMO style seems to be the most popular, I tried searching for an assembly that I can use, but all I can come up with are the style of NMO's that are used for "through the roof" mounting. My application will leave the underside of the mount exposed to the elements, however, I am unable to find a NMO mount that is waterproof on the bottom also.


So, please educate me if needed, as this is my first experience working with anything but a mag mount. Or is there another type of mount that you think would work better. Thanks!

 

[andrewsim]

In my experience leaving the bottom of NMOs exposed to the elements have not been an issue. If you are concerned just cover the bottom in silicone. But to my knowledge there are no NMOs made that are waterproofed.

 

[Steve0625]

Most NMO's have a plastic shell that snaps in place and covers the center wire and its soldered connection to the base of the mount. If you use a little silicone or RTV, you should be able to pretty well seal it up.





Another thing to do is to use a light coating dielectric grease on all metal surfaces as you install the mount and antenna. It will protect the metal from corrosion and maintain a good electrical connection.

 

[MESDA6]

I've had a NMO mounted to an "L" bracket on the hood of my van for over 5 years. The bottom is open on that type of mount also. No problem in in that time.


You can always use the silicone and/or dielectric grease noted above if you want to be 110% sure, but it shouldn't pose a problem as long as your wire is secured well and not flapping in the wind.

 

[factorone33]

With any type of antenna connection, the center element is the part that matters (i.e. the center conductor in the coax, and the antenna element itself). Everything else is just RF shielding and/or ground and doesn't carry current, nor will affect operation if it's exposed to elements (unless it comes into contact with live current of another source).

 

[FFRNDAN]

Thanks gents, I guess I won't worry about it too much then. I have some silicone laying around somewhere that should do the trick.