Everything you never wanted to know about VHF/UHF antennas

[Yukon Joe]

What Keith said, plus I'd consider some metal reinforcements for the nmo base as the fibreglass will be quite brittle around the hole. If you go this route you will want a ground strap to the plate

The ground strap is what I was wondering about.
The camper shell is quite stout. I don't know of I'll need the reinforced plate.

Thanks!

 

[t_j]

The ground strap is what I was wondering about.
The camper shell is quite stout. I don't know of I'll need the reinforced plate.

Yeah so if no reinforcement and using a ground plane less antenna no strap needed, else you need a metal plate and a strap.

 

[All The Way]

This should answer your question about grounding Joe
Grounds, RF & DC

I have a question about mounting a dual band antenna to a fiberglass camper shell.
Will it work since it is not metal? I thought the cable needed to be grounded?

If it did work, how effective will the antenna be? I understand that I need a no ground plane antenna for longer distances. But I'll mostly be using it in small caravan when traveling with others.

Just trying to figure out where to drill the hole for the antenna.... thanks.

 

[Yukon Joe]

This should answer your question about grounding Joe
Grounds, RF & DC

That is tough to follow even for an engineer!

One item really sticks out in that dissertation for my application. It says to put as much metal mass under the antenna. If I mount it to the fiberglass cap, there won't be any metal there.

The other two items to address are DC ground and RF ground. I think for RF ground, the cap would be OK, cause it is a large flat surface.

For DC ground, I already have the radio grounded to the battery. But do I need to DC ground the antenna cable at the base of the antenna? I don't think that I do. Meaning the fiberglass cap would be an acceptable place for the antenna to be mounted. Or am I interpreting this wrong?

 

[All The Way]

That is tough to follow even for an engineer!

One item really sticks out in that dissertation for my application. It says to put as much metal mass under the antenna. If I mount it to the fiberglass cap, there won't be any metal there.

The other two items to address are DC ground and RF ground. I think for RF ground, the cap would be OK, cause it is a large flat surface.

For DC ground, I already have the radio grounded to the battery. But do I need to DC ground the antenna cable at the base of the antenna? I don't think that I do. Meaning the fiberglass cap would be an acceptable place for the antenna to be mounted. Or am I interpreting this wrong?

You definitely don't want to dc ground an antenna. grounding the radio is a separate entity. You would have to use a thin steel plate on the under side of the cap and use ground strap from the plate to the body of the vehicle.