antenna placement question

Attaching the antenna to fiberglass is a real bad idea! First, you wont get a ground off fiberglass...Second, your asking for problems with the fiberglass developing stress-cracks.

If the body of the truck is fiberglass, then you can have the antenna right up next to it, and it's not going to affect your SWR in anyway-shape- or form....The radio waves wont see fiberglass, it would be like it's not even there.

If you have a high SWR you have other issues besides the antenna being to close to a fiberglass body...

Could be if the antennas are mounted on the mirror brackets, it could be the brackets are not grounded very good. Or, could be just the antenna needs tuning....Could also be bad coax or connectors shorted.

 

A "No Ground Plane" antenna might work in that location. They are made for boats and other fiberglass applications. I've never used or know anyone that has used one so I can't personally vouch for them.

Ted

 

You can do that sure! What I would do tho is run a ground strap off each end of the bar, right down to the frame of the truck...May even want to run a ground strap off the antenna mount itself to the frame while your at it...

As for the "No Ground" type antenna's, thats another option, I personally have never used one, and from things I have read from others that have, was not very good...That would have to be the last thing I would try...

 

Ok I asked this in my other thread and never really got an answer but I have my wilson fgt-4 mounted on the bar just above the back window of an 05 columbia. I'm not sure how good of a ground that is, being that bar is just bolted on using 2 little bolts through the back panel of the cab. The best that I can figure is those 2 bolts hit some kind of metal framing behind the rear panel skin?
In any case my swr, checked today with a new external meter, is 1.9:1 on 1 and 40 and 1.7:1 on 19. Not as good as I would like but certainly good enough especially given the questionable location of the mount which I like for a couple reasons. It's in the center of the vehicle which is supposedly good reception wise and given the places I go hauling mulch with a walking floor it is a lot less likely to get broke off by low branches and such compared to a mirror mount. Also it gets me high enough that the majority of the antenna is above the roof line and the top foot of this top loaded antenna is above the wind fairing and the top of the trailer which is shorter than a typical dry van.
My conclusion is this works quite well for me at least with this particular antenna, I get out quite well with it (at times a good 10 miles with a stock 29) and my swr is definitely acceptable as well. I'm just not sure how it's being done and I really would like to know. lol

My co-worker has a wilson 2000 trucker mounted in the very same location and can't get his swr below 3. My only guess is the fgt-4 is much more forgiving when it comes to swr and ground plane than the 2000 trucker. I also think the top loaded antenna is best for this type of install. We're both using super mini 8 coax.
One other difference that I'm not sure matters at all is my radio is mounted to the dash with the bracket giving the radio itself somewhat of a chassis ground while his is just sitting loose in that little overhead compartment?

Any thoughts on all of this? Cuz I sure would like to know why mine seems to work better than his and with a much better swr reading. I know he would too and might help the original poster out here as well.
My co-worker is running a 300 dollar galaxy with a supposedly much better antenna and I know it just chaps his hide! He's all but given up and said it she blows she blows.

 

Could be several reasons why your set-up is working, and his is not...

Could be anything from that bar not having a very good ground on his truck, to bad coax, antenna not tuned, bad connector, shorted antenna...etc.....

I would start however with running ground straps off that bar to the frame...and be sure to use flat-ground braid, and scrape off any dirt, rust, or paint before installing your ground strap...(Old coax makes good ground strap...strip off the outer plastic shield, then pull out the center conductor wire, and just flatten out the ground braid, and you have some excellent ground strap!