2m antenna on a Wrangler with a soft top?

Started by raybiker73, October 28, 2014, 03:33:15 PM

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raybiker73

Just traded in the ol' Jeep Liberty on a new Jeep (2015 Wrangler Willys Wheeler), and I'm faced with a dilemna. Currently, it has a soft top installed. I'll eventually buy a hard top for it, but for now, I'm wondering where to mount a 2m antenna. I really don't want to drill any holes in it, and a rooftop mag-mount is out for obvious reasons. Anybody here have a Wrangler with an antenna mounted? I figured I'd seek some advice before doing anything, so I'm open to suggestions. Thanks!

New baby pic...


gil

#1
Nice Ray  :)

I would weld a 3ft steel tube on the back bumber, and put the antenna at the tip of it, with the coax going down inside the tube to the inside of the bumper... Nice, clean, no visible wire, and the antenna base is at roof level. You would probably have to weld small braces at the bottom, but after painting, it would look neat. That way you also don't have to drill a hole anywhere on a new car.. Well, except the bumper..

Gil.

Photo attached: Real Willys I had, about 27 years ago.. Sold it to finance a trip to Australia..


KK0G

2015 Wrangler Willys?! That's not a Willys, it's blasphemy! Karl Probst is spinning in his grave right now! 8)

Just kidding, nice ride. As you can probably tell though I'm sort of a Jeep geek, although I haven't actually owned one in over 10 years now.

As to where to mount an antenna; heavy duty ball mount on the right rear quarter. Yeah, yeah, I read that you didn't want to drill holes...... too bad, get over it, punch the holes and mount it right. You can thank me later. ;D
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

Jim Boswell

Hello,
     Gil had a good idea. Gill's idea would be the most perm. fix. How about this: make a 2meter J-pole using 300 ohn twinlead and house it in 1/2 gray PVC pipe. Make the antenna and slide it into the PVC. Then clamp the PVC using hose clamps off the back of the jeep. The J-pole does not require a ground plane and you could try different lengths to obtain the best coverage vs height limitations. Another way to go would be to use a marine antenna because they function without a ground plane.
Keep us posted on what you do, neat ride, looks like too much fun.
73'S  KA5SIW

Quietguy

#5
Quote from: Jim Boswell on October 29, 2014, 11:29:51 AMmake a 2meter J-pole using 300 ohn twinlead and house it in 1/2 gray PVC pipe.

I did that some years ago and had a lot of trouble getting a good SWR on the antenna.  I chose gray electrical conduit because it would be harder to see against the sky than white water pipe.  Unfortunately, I failed to take into consideration that the gray color in my electrical conduit had come from carbon additives - so it detuned the antenna.  By the time I figured that out, I had finally gotten a reasonable match but it took a lot of trial and error with the antenna analyzer to get it - measure SWR, take the antenna out of the conduit, trim, reinstall in conduit, measure SWR, remove from conduit, trim, reinstall in conduit... ad nauseum.  I could have saved a lot of time and frustration if I had used white water pipe and painted it.

I don't know if all gray PVC pipe contains carbon, but I would choose something different if I did it again.  If there's enough in there to detune the antenna then there is enough to absorb some of the power.

Wally

kc0rzw

One of the guys around here has a screwdriver antenna mounted on one corner of the front bumper, and I believe his 2 meter is on the other corner


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cockpitbob

The twinlead J-pole in PVC is a good idea.  J-poles work very well and don't need a ground plane.  The PVC's high dielectric constant does throw off the resonant frequency (and possibly the impedance) if it isn't designed for it though.

I have this 2M/70cm one in my attic.  It works great.  It's designed by a college professor and made by students (he's a great guy and not making any $ on it).  To save shipping you provide the PVC.  The only down side to this antenna is he designed it for SCH-200 PVC which can be hard to find.  If you use the more common SCH-400 or 100 your SWR will be off a bit.  I would sand it and paint it with Krylon Fuse spray paint.