Antenna grounding

[katt02]

hi all,

I was installing my antenna recently and I though of this what if question. I tried google, but I found no answer.

What would happen if I were to install an antenna on a car that requires grounding, but I provide it nothing to ground with? Would it simply not work as well or would it damage some components?

This is simply a hypothetical question.

Katt

 

[W5lz]

Would it work? Maybe receiving stuff but doubtful for transmitting. Most mobile antennas or mounts connect to the vehicle's body and that is the "ground". Just don't push that 'talk' button! How well would it 'hear'? No idea.

 

[ko6jw_2]

How are you mounting the antenna? Most mounts are grounded. Mag mounts are not except for whatever capacitive coupling there is between the mag mount and the car body.

Not grounding to the body will mean that there is not ground plane for the antenna. Performance will be poor.

Also, remember that if you are transmitting the radio should be grounded directly. Don't rely on the antenna ground.

 

[katt02]

I though of this post with a diamond antenna K412 lip mount. I noticed that it came with a small metal plate that would go in between the screws and the car that was for extra grounding. Made me wonder what would happen if you did not put it there.

 

[AK9R]

I noticed that it came with a small metal plate that would go in between the screws and the car that was for extra grounding. Made me wonder what would happen if you did not put it there.

If you tighten down the setscrews against that thin metal plate, that just squeezes the plate against the paint. Paint is generally not conductive. The only reason for that plate is to keep the setscrews from penetrating the paint and digging into bare metal. But, you want need contact with bare metal if you want the mount to be grounded.

Your options with lip mounts are let the setscrews dig into the bare metal so you get a good ground. But, if you do that, you risk having rust form where the setscrews dig into the bare metal.

If you live in NE PA, you probably deal with a lot of salt on the roads in the winter. My experience with Diamond's fancy lip mounts is that salt and water get into the mount, work their way to the bare metal (cast aluminum) of the mount, and corrosion starts.

 

[W5lz]

The bottom line is that there has to be a completion of the 'circuit'. Any/all means of this completion will have 'faults/problems'. Which of those 'faults'/'problems' are you willing to deal with or accept? So it's a matter of 'degree'. I've found that the rust from a metal to metal contact completion of circuit is pretty easy to deal with, so, will probably use that method again. I've also found that an indirect completion of circuit is also pretty easy to deal with, as in a mag-mount. Both mean that there will be maintenance to keep that direct or indirect completion of circuit usable.
I have never seen a 'perfect'/'pristine' vehicle traded in on another one (and don't expect to). And, within reason, minor damage is absolutely, dead-nutz common and shouldn't make any significant difference in the value of said vehicle. Another aspect of those set-screws digging into the body metal is that it usually happens on the back-side of that trunk lid/hood/etc. If the evaluator is searching that hard to find faults, take your business somewhere else. That doesn't mean you can expect them to totally ignore a 'roll-over' type thingy...