Odd SWR Issue With Jeep Wrangler

[JayMojave]

Hello ELV: Looks like a good install there. You don't want the antenna next to metal if avoidable.

The MNO mounts are a little on the Mickey Mouse mode even for the stock designed antennas as the connection between the antenna and mount those using a spring loaded arm to make contact. I have used the Comtelco Antennas that use a coil spring with good results, for CB, VHF, and UHF bands.

I have made brackets for the modern Jeeps, removing the RH Brake Light assembly and making a bracket that fit in between the light assembly and Jeep body with a L bracket made a good antenna mount. The Jeep owners wanted a antenna mount some what low but wouldn't get whipped off with trees or brush being mounted on the side.

Sounds like you have the problem handled good going.

Jay in the Mojave

 

[comoman]

I have a little bit different issue with my 2012 Jeep Wrangler in addition to high SWR.

I'm installing a 10 meter radio and Sirio 10 meter antenna in my 2012 Jeep Wrangler. I've run into an SWR issue and not sure how to deal with it. I'm using an MFJ- 259B antenna analyzer and can't get below 2.7 SWR at 50 ohms. The Jeep antenna mount is on the tailgate and doesn't have a decent ground so I installed a braided ground strap between the body and the tailgate. Something I find strange is that with the radio off I get 0 ohms through the ground wire from the radio to the vehicle chassis ground. When I turn the radio (Stryker ST 89MC 10 meter) on, the ohms reading on the ground is 0.16k to 0.20k ohms. The coax is new and check out ok.

I've got a suspicion the resistance on the ground wire is contributing to the SWR issue. No matter what I do the SWR is high. The resistance reading I'm getting with the radio on is what has me also confused.

 

[prcguy]

I commented on this problem on another thread but now that I see a pic my opinion is you will never achieve a good match with the setup as shown. That antenna needs some flat sheet metal under it for a ground plane. What you have done by mounting its feedpoint waaaaay above any flat sheet metal is made something like a dipole where the whip is one half of the antenna and the coax, elevated bracket and ground lead are the other half of the antenna and none of that is resonant at 27MHz. The braided ground lead is not really doing anything in this install.

I would take it all apart and mount it so the base of the antenna is up against some major sheet metal for starters and then apply the capacitor trick in my other post if needed. You can run a temporary test by adding a couple of wires 3ft to 6ft long off the grounded base of the antenna and out to the sides like ground radials. The antenna should tune fine or at least much better and that will tell you its actually working but just needs more ground plane under it.
prcguy

 

[invader729]

leep wrangler swr problems

i own a 2008 wrangler that i used an " arizona" off road antenna out to the spare tire and recently swapped it out with the Terraflex SS mount because my long time perfect match went south to a flat 2.1-1 across the entire 11 meter band including the outbound frequencies . i found out that the reason for this problem, that would go away if i opened the tail gate, was due to the rear window defroster. one of the connections to the defroster had broken loose causing the defroster wires to reek havoc on my swr. once i repaired the connection to the
defroster grid, my swr went back to normal when the gate was closed. completely opposite from what the norm would be. i used a Rig Experts AA-54 antenna analyzer for tuning the antenna. K-40 Power Whip four foot. hope this might be of some help to the 2013 wrangler owners post.