An odd antenna tuning issue

Lyv Wire · #1 (**permalink**) 01-19-2009, 10:04 AM

I have a wierd issue with ONE tractor in our fleet; I usually run a Francis 4.5' on a vise grip with my XM radio antenna. With ( this ONE being the exception) every tractor in the fleet : the SWR on this rig shows 1.3 without fail . Now there is one tractor that I seem to draw quite often has a wierd effect on my antenna rig . I can't get an SWR lower than 2.5 without retuning or changing to a different antenna ( with a tuneable tip ) . All tractors are the same model , all equipped the same . I always have to either remove the stinger (from fiberglass) or push the stinger down an inch or so . Doesn't matter which mirror or even across the hose tender bar. I just thought that was wierd . I thought maybe a ground problem but, after testing this particular tractor , it is grounding all the way to the frame . STEEL CAB I didn't know if any of the rest of the sliseater gang out there ever had the same results. I wonder why ???

mossbackman · #2 (**permalink**) 01-19-2009, 02:45 PM

It's possibly some sort of weird phenomenon thats never been seen before and will never be seen again(like project bluebooks explination for many UFO sightings)

Lyv Wire · #3 (**permalink**) 01-19-2009, 02:54 PM

Quote:

Originally Posted by mossbackman

It's possibly some sort of weird phenomenon thats never been seen before and will never be seen again(like project bluebooks explination for many UFO sightings)

I all likelyhood .....a conspiracy to sidetrak trucker's communications !

easttnhillbilly · #4 (**permalink**) 01-22-2009, 01:13 PM

i had this happen with some trucks in our fleet same antena setup i solved it by running a ground wire hooked aligator clips to snt. mount the other end to the exhaust u bolt under cab worked fine and was easy to move

Lyv Wire · #5 (**permalink**) 01-22-2009, 03:21 PM

Thanks for the tip HILLBILLY I may end up trying that too !

I went with a FIRESTICK II ( with tuneable tip ) & it worked great w/ LOW SWR !! I'm a simple man I just don't like having to carry two antenna rigs !

fr8rookie · #6 (**permalink**) 01-26-2009, 10:04 PM

Sounds like a shielding with the trucks electronics,something may have been changed or even not hooked up right. A rebuilt alternator or maybe an ECM not installed or rebuilt correctly. I had some problems in a KW when I ran a 350 on the high side. If it was raining or just wet it would be fine but if it was hot and dry forget it, all the warning lights would light up. Tried every hookup known.