Antenna Recommendations for a Jeep

[SublimeHiPpOs]

15 inches would be the length for the lowest designed frequency. At 450MHz, the whip would be 9 5/16th's. Add the length of the coil and the length of the spring, and you're probably pretty close to 15 inches.

The full uncut length is 12 3/4".

This is the one I ordered.

BB4502NS: 450-470 MHz Mobile Base Coil NMO Mount Antenna With Spring-No Metalic Ground Plane Required

The Laird / Antenex BB4502NS is a 12.6 inch long, Black base coil, omnidirectional whip antenna for operation in the 450-470 MHz UHF band, with NMO base and spring. No metal ground plane required. *This Antenna Requires a NMO Mount. Please click here to find all Thru-Hole NMO mounts or Magnetic...

www.arcantenna.com

The bag it came in has the correct model # and the cut chart printed on it matches the one on the product page. So I guess they just run shorter than listed.

 

[mmckenna]

The full uncut length is 12 3/4".

This is the one I ordered.

BB4502NS: 450-470 MHz Mobile Base Coil NMO Mount Antenna With Spring-No Metalic Ground Plane Required

The Laird / Antenex BB4502NS is a 12.6 inch long, Black base coil, omnidirectional whip antenna for operation in the 450-470 MHz UHF band, with NMO base and spring. No metal ground plane required. *This Antenna Requires a NMO Mount. Please click here to find all Thru-Hole NMO mounts or Magnetic...

www.arcantenna.com

The bag it came in has the correct model # and the cut chart printed on it matches the one on the product page. So I guess they just run shorter than listed.

No, that sounds right. 15" is the full length of the assembled antenna:
Whip length + Spring + coil

The cut chart tells you how long JUST THE WHIP needs to be cut to be close to resonate at the desired frequency. You should cut it a 1/2 inch longer, then use your SWR meter to do the final trim/adjustment.

 

[niceguy71]

I've got a Jeep JT pickup and the roof and entire top end is fiberglass with removable roof panels. The only suitable place I can find is top of the hood using a trunk lip mount near the hood hinges. The mounts that go between the hood and fender put the antenna several inches below hood level, not that bad for CB but nearly a 1/4 wavelength below top of the hood on UHF or GMRS.
I have two NMO mounts on the hood and use various antennas for several different radios. Here are pics of the drivers side with a Larsen dual band amateur and a bare NMO on the passenger side.

View attachment 149972

View attachment 149973

On the drivers side there is an easy cable pass through point below the mount but the passenger side is much more difficult to bring an antenna cable in through the firewall. My passenger side cable actually goes into the frame and pops out under the rear seat where I have a couple of radios mounted.

I also have a bracket with NMO mount on the upper bed rail right behind the rear window but I don't recommend that for just any antenna due to the lack of ground plane. It seems ok for UHF or GMRS but it starts to be a problem at VHF and for CB its not recommended.

looking to get a good CB antenna on a Jeep TJ .... the lip mount looks like a good Idea but I always thought the bottom of the CB antenna was base loaded and it would need to be above the windshield frame?

 

[prcguy]

looking to get a good CB antenna on a Jeep TJ .... the lip mount looks like a good Idea but I always thought the bottom of the CB antenna was base loaded and it would need to be above the windshield frame?

The hood hinge area works well and the windshield frame is not a big problem. The loading coil doesn’t radiate much, most signal comes off the lower portion of the whip.

 

[niceguy71]

The hood hinge area works well and the windshield frame is not a big problem. The loading coil doesn’t radiate much, most signal comes off the lower portion of the whip.

what would you suggest for a CB antenna that would work with that mount?

 

[nokones]

As you probably know, Jeeps are a very poor platform for mounting an antenna. It really won't that much difference on where you mount it, you will have a good side and the opposite side will practically a null side to some degree. You will have adequate performance within a group on Trail Runs.

I went with a Larsen Glass-Mount and tuned it accordingly and my VSWRs are about 1.2:1 at 50 watts on 462 MHz freqs and about 1.6:1 with the same power on 467 MHz freqs. I mounted my antenna on the rear window. I was surprised in the performance of this antenna not only hitting repeaters at far distances but also the distance between my Jeep and another mobile on a simplex channel.

 

[prcguy]

what would you suggest for a CB antenna that would work with that mount?

A Larsen or similar base loaded NMO antenna would work fine. I would not recommend a heavy antenna like a 4ft Firestick which would stress the mount. If you can find the now out of production wideband Antenex/Laird CW27 it will cover about 26 to 31MHz without tuning for both CB and 10m use. It’s also got a thin 67” long whip that radiates like a Bastaad.

 

[nokones]

As for my CB antenna, several Jeep suppliers have a mounting bracket that affixes to the two bolts on the rear door hinge or to a couple of mounting bolts of your spare tire carrier mount. The antenna mounting bracket is very stout for a Firestik with or without a spring. I don't remember where I got my cable. I think it may have been Rugged Radios. I'll try to take a couple pictures and paste them to this site.

I'm running with a 5 Ft. Firestik II tuneable antenna and Firestik's strongest spring with a quick disconnect and my mount is affixed to the rear door hinge.

 

[prcguy]

As for my CB antenna, several Jeep suppliers have a mounting bracket that affixes to the two bolts on the rear door hinge or to a couple of mounting bolts of your spare tire carrier mount. The antenna mounting bracket is very stout for a Firestik with or without a spring. I don't remember where I got my cable. I think it may have been Rugged Radios. I'll try to take a couple pictures and paste them to this site.

I'm running with a 5 Ft. Firestik II tuneable antenna and Firestik's strongest spring with a quick disconnect and my mount is affixed to the rear door hinge.

Hanging an antenna out in space like on a spare tire mount does not provide much ground plane and will reduce performance and cause tuning problems. Door hinge is a little better but still not great.

 

[niceguy71]

A Larsen or similar base loaded NMO antenna would work fine. I would not recommend a heavy antenna like a 4ft Firestick which would stress the mount. If you can find the now out of production wideband Antenex/Laird CW27 it will cover about 26 to 31MHz without tuning for both CB and 10m use. It’s also got a thin 67” long whip that radiates like a Bastaad.

wow that does sound good 5 and a half feet tall! that should get above the windshield.... hopefully the antenna bouncing around is not distracting when driving? I have always heard the Larsen is professional grade... if we go that route I"ll call the larsen company and get the antenna ... mount... and coax..
thank you PRCGUY

 

[niceguy71]

As for my CB antenna, several Jeep suppliers have a mounting bracket that affixes to the two bolts on the rear door hinge or to a couple of mounting bolts of your spare tire carrier mount. The antenna mounting bracket is very stout for a Firestik with or without a spring. I don't remember where I got my cable. I think it may have been Rugged Radios. I'll try to take a couple pictures and paste them to this site.

I'm running with a 5 Ft. Firestik II tuneable antenna and Firestik's strongest spring with a quick disconnect and my mount is affixed to the rear door hinge.

I never had any luck with any fiberglass antenna... how does it get out????