SLROC Forum

Just been given (?15) a CB radio & SWR meter with Magnet aerial.
So thats it decided that I should get a CB.

Any tricks to  install -noted about the steel plate. But whatdo I do with an SWR meter?

You'll need a ground plane for the CB or you'll fry it with SW. So if you have a magnetic aerial, you'll need to find a big steel horizontal area to stick it on. On my 110 I couldn't find one so I went for a gutter mount.

The SWR is easy to use: http://www.4x4cb.com/public/page.cfm?CatID=645

A lot easier demonstrated than described!  It's an indicator used to adjust the antenna so that it works at best efficiency with the radio. Your antenna was probably adjusted to wherever it had been fitted in the past, and is probably already close to maximum efficiency.

Once you have decided where you will be using it you can adjust it precisely to your own vehicle. Have a look at this site for how to do it:-
http://www.offroaders.com/info/tech-corner/reading/swr.htm

The roof of the Land Rover makes a great ground plane but unfortunately a magnetic mount won't stick to it.  What many people do is to pop-rivet on a small steel plate where they want the magnetic mount to sit.

Enjoy!

Ruari,

Depends how much use you want to make of it. As said the Aluminium roof does not work with a magmount magnetism only works on ferous based metals as I'm sure you know.

If you are only thinking of using it for GRR and Tyro's then I would stick the mag on the front bumper. Bill (of Buffalo fame) ran all Sunday with his mag mount on the front bumper and its was working fine. Caked in mud but working fine.

One of the biggest issues I had with my 90 was interference from the injectors and heater motor. Thankfully the 110 has none of these issues.

I have attached a 3mm plate to the back of my roof rack and that gives me the ability to mag mount although I do not need to use them. I find that the steel plate electrically attached to the Aluminium roof gives me a very good ground plane.

An SWR meter is as said not rocket science however before you connect the set up try first to make sure the co-ax is not shorted inner to outer. That will knacker the rig if you try to Xmit.

failing that take a run over and we can fix it up, I'm not too far from you

T

Cheers for the answers. Seeing as it's raining, looks like a good day to do the research.
Initially I was going to use the bumper with a long term plan of mounting the aerial higher up. Does the ground plate need to be over a certain size? I was thinking of attaching the plate to the top of the ladder, so about 150mm wide. Just big enough for the mag base but the ladder is bolted to the alu cab, would that be suitable?
Initially it will be GRR and the Driving Day, but if it has the potential for more....

My days of CB radio are far behind me (I used to have an 8m or so antenna on the roof of the house many years ago) but I'll try to answer from memory.

The ground plane is a reflector for your aerial. Its size and shape are important. If it's too small, you'll get high SWR, you might create interference, and you will lose efficiency. If it's too big, you can also suffer from high SWR (although I've never experienced that). 150mm sounds very small to me.

Note that the shape of your ground plane and the location of your aerial on it will also affect the shape of your signal. Typically, if you put your aerial on the edge of the plane, the signal will go across the plane away from the aerial. If you want a nice omnidirectional signal, the best is to put the aerial right in the middle of the plane (e.g. middle of the roof).

From reading the links it looks fairly straight forward.  Got over the first hurdle - broken wire on the power supply
I'm going toget a steel plate te width of the roof and mount it on to the spot light bar. That should do the trick, then I can do the installation & adjust aerial length.
Thanks for the advice.