Ham Radio Antenna Location

P_D

P_D

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Oct 28, 2019
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Location
Texas
I’m installing a 2m/70cm set up in my TJ with a soft top.

I know this has been covered, and I have read through tons of posts about this subject. There isn’t much consensus on NGP vs ground-plane or the effectiveness of antennas on the bumper etc. I have noticed that there seem to be two types of people who weigh in on these questions: Hams who drive Jeeps, or Jeep guys with their ham license. I’m not sure which category I fall into yet. I hold a General, but I’ve only been a Ham since May. And I am just getting started with trail riding

Here is what I’m trying to accomplish:

I’d like an antenna that will help me hit repeaters in areas where I go off-roading, and maybe some simplex comms with people on the trail, but also one won’t get bent in half or peeled off my Jeep by the tree limbs in East Texas. Oh yeah, I forgot to mention I’m cheap and I don’t want to drill any extra holes in the body. I am running an HT thru a 30W VHF amplifier. The UHF will pass thru the amp when it’s off, but it will only be 5W so I’m thinking UHF will be more receive than transmit...

One option is a lip mount on the tire carrier swing pictured below. Pros: centered on the vehicle, more of the antenna is above the roof, looks cool. Cons: grounding is an issue (I’m not sure if this is true, but I’ve read statements to that effect), whatever length of antenna is sticking up above the roof is liable to come into contact with tree limbs etc
1594360172818.jpeg

Another option is the tail-light bracket mount. Pros: protected from trees etc, the bracket contacts bare metal, so the ground is good, also looks cool. Cons: body shields antenna reception and transmit.


1594361358003.png

Next option is windshield frame. Pros: less shielding of RF signal, more of a traditional ground plane. Cons: Less shielded from branches, I don’t see a tidy way to run the wire back into the tub, lots of leftover coax (I don’t have the tools to trim and attach connectors to coax)
1594361914223.png

I know all mobile antennas are compromises. Any suggestions?
 
Mounting the antenna any place other than on the top of the vehicle is a compromise for RX/TX.
I have seen people mount antennas to the front fender and hood which to me are a visual annoyance while driving.
I removed my 3rd brake light mount and installed a circular 3rd brake light; then used the hole that the brake light wiring passed thru to mount a PL239 with fender washers. This location uses the mounting strength of the tire carrier, the mount is centered in the rear and has a decent ground. The antenna I use is a Diamond SG7900 that sticks up about 2.5' above the soft top and has decent RX/TX, but this is the only location that made sense for me.
Mounting on the rear corners would also be directional and prone to be torn off while on the trail.
My present problem is where I am going to mount the radio...
IMG_8085.jpg
 
Last edited:
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I run the terraflex tail light bracket and a half wave 2/70 antenna. I do not have any complaints and it goes in my garage without hitting. Have a 3’ fire stick on the other side for the chicken band. I don’t like the antennas up front.

-edited. I think the antenna I run is the diamond NR770HB
 
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I use Teraflex tail light antenna mount brackets - CB on drivers side, ham on passenger side. The NMO antenna mount, 3/8" stud mount, and CB quick disconnect are from Breedlovemounts.com.

The two dual band antennas that have given me the best results are the Larsen NMO 2/70B and the shorter Larsen 2/70SH (shown in the photo).

Ham Radio Antenna Mount 07 04 19.jpg
CB Antenna Mount 07 04 19.jpg
 
Hokahay said:
Stu Olson has write-ups galore on his website.

If it doesn't answer this question for you maybe it will at least provide some interesting reading on a variety of subjects.

https://www.stu-offroad.com//misc.asp
KX4WQ

73
Click to expand...
Stu's website is a treasure trove of useful information, he's a really good guy I had the pleasure of wheeling Death Valley with many years ago.
 
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I use a magnetic mount on the center of my hood, run the wire through the gap between the hood and the body on the drivers side. I enter the firewall down there as well. The hood offers a pretty good ground plane. With a black antenna, I don’t really notice it. It’s also a little right of the road in my field of view.
 
I think I’m going to use an NMO lip mount on my tire carrier swing gate. Thanks for all the input.

I’ll post up my rig install when I’m done.
 
Mr. Bills said:
I use Teraflex tail light antenna mount brackets - CB on drivers side, ham on passenger side. The NMO antenna mount, 3/8" stud mount, and CB quick disconnect are from Breedlovemounts.com.

The two dual band antennas that have given me the best results are the Larsen NMO 2/70B and the shorter Larsen 2/70SH (shown in the photo).

View attachment 175773View attachment 175774
Click to expand...
Do you know what size hole that bracket needs to have to install an NMO cable? I bought this bracket https://www.amazon.com/gp/product/B07HJ314L2/?tag=wranglerorg-20

to use with this NMO connector https://www.amazon.com/gp/product/B0842B1WFS/?tag=wranglerorg-20

but I'm not sure it will fit or if I need to ground it in any way. It is for a 6db GMRS antenna.
https://www.amazon.com/gp/product/B084BPXNC5/?tag=wranglerorg-20
 
namunyoska said:
Do you know what size hole that bracket needs to have to install an NMO cable? I bought this bracket https://www.amazon.com/gp/product/B07HJ314L2/?tag=wranglerorg-20

to use with this NMO connector https://www.amazon.com/gp/product/B0842B1WFS/?tag=wranglerorg-20

but I'm not sure it will fit or if I need to ground it in any way. It is for a 6db GMRS antenna.
https://www.amazon.com/gp/product/B084BPXNC5/?tag=wranglerorg-20
Click to expand...
You're not going to find many brackets that are made for NMO connectors. I usually buy a CB antenna bracket and then just drill the hole out for NMO using a step-up bit. Every bracket I've done this with has had plenty of material to drill out.

As for ground plane, that's a little more tricky. I can't tell for sure but that looks like a full wavelength antenna (full wavelength at 462 Mhz would be 25.5 inches) and that antenna shows to be 32 but that includes the spring, base, etc. I'm a little perplexed by the coil in the center because I see that usually used with dual band antennas as a separator for the different bands (VHF/UHF), so maybe it's achieving a dipole effect with that choke?

Regardless it's always a good idea to check your installation with an SWR meter or an antenna analyzer before you start trying to transmit just to make sure that you're antenna is going to play nicely in the location that you've put it. Objects next to the antenna can very easily attenuate your signal and change its tuning characteristics.
 
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samobius said:
You're not going to find many brackets that are made for NMO connectors. I usually buy a CB antenna bracket and then just drill the hole out for NMO using a step-up bit. Every bracket I've done this with has had plenty of material to drill out.

As for ground plane, that's a little more tricky. I can't tell for sure but that looks like a full wavelength antenna (full wavelength at 462 Mhz would be 25.5 inches) and that antenna shows to be 32 but that includes the spring, base, etc. I'm a little perplexed by the coil in the center because I see that usually used with dual band antennas as a separator for the different bands (VHF/UHF), so maybe it's achieving a dipole effect with that choke?

Regardless it's always a good idea to check your installation with an SWR meter or an antenna analyzer before you start trying to transmit just to make sure that you're antenna is going to play nicely in the location that you've put it. Objects next to the antenna can very easily attenuate your signal and change its tuning characteristics.
Click to expand...
Thanks, I'll see how much I need to drill out when I get it in the mail tomorrow.
 
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