Earthing points at the rear?

I must be lucky then, my mount is on the spare wheel bracket.
My SWR reading, 1-1.

There seems to be some confusion here between a ground - ie: an earth to the battery and a GROUND PLANE.

Obviously the electrical supply to the CB needs a good earth, ideally straight to the battery, but I've run one off a cigarette lighter with good swr reading.

The antenna's ground plane is just a large area of steel that need not be linked to the battery. I'll not pretend to know how it works but that's what it needs. The spare wheel carrier can do it, I have used this also.

I now use my cage. I have used bodywork also on my SJ.

Gutter mounts need a thick cable to a large area of steel.

Aluminium is not a good GROUND PLANE despite being a good conductor of electrickery. This causes issues for the LR boys!

Have a read about it on Thunderpole's website.

Kirkynut

Vaxxi - not now. At first I was picking up some interference which I eventually decided was the fuel pump. When I installed the aerial mount I thought it would be a good idea to run a separate earth to the bottom of the aerial and to the battery earthing point. However after a bit of experimenting I found that this actually made the 'white noise' worse. So I removed the earth wire and reception improved, and now it works fine. For some reason I don't understand I get even better reception on am rather than fm. I am a member of a couple of French off road clubs and one uses am and the other fm to keep in touch on their outings. The CB I use is a Midland Alan 78 Plus Multi which works on a range of frequencies for various European countries. The swr changes between say channel 1 and 40, and also between different country frequencies, but is generally low.
More confusion!

kirkynut wrote: Aluminium is not a good GROUND PLANE despite being a good conductor of electrickery. This causes issues for the LR boys!

It's not that Aluminium doesn't make a good ground plane - it does - it's that you get electrolytic corrosion around the junction between the steel and Aluminium which increases the impedance of the connection and leads to poor SWR.

An option which works reasonably well is to buy a sheet of Galvanised steel sheet (or Zintek) - perhaps 50cm square (or as big as you are prepared to go) and mount the antenna to that and that to your roof rack.

Si

Would something like this work as an RF Ground?
you'd just have to be careful you didn't loose it in the woods!!

So long as it's made of metal (not body filler) - it looks ideal. Nice and high up too!

Si