FYI

[jims-terrano]

Do you think that the allen bolts on the bit that fit on the roof is a good earth?

Just thinking if so, I could make an earth lead from one bolt, run it through the rail to the mount. But I'm still confused as to way when I used a jump lead to earth the mount nothing changed?

Thats my thinking too Paff, think that's what I'll do if I get around to fitting the bars on my 05 plate. They are fitted using a rivnut into the roof skin so unless there's a lot of corrosion between the nut and the skin it should be fine. If you are clever you should be able to do some fancy drilling and hide most of the earth wire too.

 

[supergnome]

Maybe you looking at the wrong thing? When you touch the antenna you don't earth it, you change the capacitance in it. Have you tried any other ant's in the same base to see what they perform like. You could try the antenna on a known ground plane and check its swr or mount it connected to the tow bar( temporary ). Have you shortened the coaxial cable and that its of a good grade. It's going to be a simple solution when you find it, just keep going. David.

 

[Paff]

...It's going to be a simple solution when you find it, just keep going. David.

Hi David,

Yeah I'm sure it is. I will try the CB antenna on the other mount and see. Still not 100% sure if any earthing with help if the jump lead didn't help. I think that you could make up an earth lead from the hidden allen bolt, run it through the elbow and out of a drilled hole in the rail, then to the mount... but that will have to wait until the storm has gone over and I have the time. :naughty

 

[supergnome]

If you have or can borrow a known good antenna to swap, it will confirm the mounting of the base is good or otherwise.

"It was proven when I used a mag mount and the SWR was nearly 1.1:1 " Just read this in your previous post. Mag mounts are not touching the roof or they would scratch!!! So think you may have a duff twig

 

[jims-terrano]

Just a suggestion, check your coax and connections with a multimeter. Could very well be a strand of braid causing a short or perhaps not connected.

 

[Paff]

Been there done that guys, coax checks out OK and is a new length. The halfbreed id superb on the mag mount, but way our on the rail mount.

 

[macabethiel]

Roof rails

My guess is that as a Manufacturer you want to fit rubber gaskets between the roof rails and the bodywork to prevent galvanic corrosion and thereby prevent body rot.

Any two dissimilar metals in contact with one another will cause a very small flow of electrons from the higher state metal to the lower one this shows itseself as oxidation / corrosion.

 

[AlexD333]

My guess is that as a Manufacturer you want to fit rubber gaskets between the roof rails and the bodywork to prevent galvanic corrosion and thereby prevent body rot.

Any two dissimilar metals in contact with one another will cause a very small flow of electrons from the higher state metal to the lower one this shows itseself as oxidation / corrosion.

Good shout, amen on that one :thumb2