Mounting antenna on roof
Installing antennas into the rails of a roof cargo/luggage rack is doable if you keep two things in mind.
Most, yet not necessarily all roof racks are installed into automobile roofing with expanding plastic inserts. This prevents the roofing rack itself from becoming chassis grounded. While that does not impact its function as a roof rack, it can impact your antenna installation. It will be far better look at the roof rack grounding before making the antenna system buy. If rack is certainly not grounded then you will want to ground it to be able to make use of a standard ground jet (GP) dependent antenna system. If you don't wish to ground after that it it is important to utilize a no-ground-plane (NGP) antenna system.
All standard floor airplane (GP) centered antennas require a chassis grounded antenna mount. If you clamp or bolt a bracket to an ungrounded rack you will have trouble tuning the antenna and gratification are affected. Testing the ground. If antenna, the mount therefore the coax had been set up, disconnect the coax from the radio if your wanting to search for continuity between your mount in addition to vehicle human body. Otherise, you are getting a false reading straight back through the coax cable through the radios ground link. If you decide to run a ground cable to the rack, use either a grounding braid or a wire this is certainly 12ga or thicker and try to ensure that it it is since short as you can (Chassis grounding does not mean that ground cable has got to be attached into cars framework. Any typical floor location is a part of the vehicles framework surface).
Other things to keep in mind if utilizing a GP antenna system anodizing (on aluminum), powder layer and paint are insulators. If your rack features an insulating finish (although it's chassis grounded) you certainly will nonetheless should be sure the antenna mount features experience of the grounded rack. Counting on a ground through the coax, as previously mentioned, is an SWR issue waiting to take place.
GP antenna methods, when precisely tuned over the right floor airplane, produce better field-strength than do NGP systems. If you have available ground airplane and want optimum performance, checking out the procedure for grounding the rack therefore the mount would be really worth your time and effort. But if you are simply a laid-back user who wants to consult with other individuals in automobiles that you will be traveling with or wish an occasional highway check, you are able to miss out the grounding demands of a GP system and install among the NGP systems on your own ungrounded roofing rack.