Ham radio and antenna install (w/pics). D710G + hard top antenna

[vap]

First, the radio mount bracket. Dirt cheap. Easy to DIY. You get the idea.

My goals were to move it away from elements and moving cargo, while keeping the antenna cable short and radio connectors accessible.

The radio is Kenwood D710G, but you can use any hole pattern to mount any radio available.

The power wires, both +12 and ground, goes directly to the battery, through a driver side clutch cable grommet in the firewall. I used 4 AWG marine tinned battery cable to minimize voltage drop, together with marine battery fuses both for ground and +12. Two post marine terminal (as seen on the picture) is used to go from 4 AWG to 10 AWG to RIGrunner.

Now, to the antenna mount.

It is very hard to find a good place for an antenna on a Wrangler. The only way to get a nice symmetrical ground plane at the base of the antenna is to drill a middle of the hard top and glue metal sheets underneath.

I wasn't sure about drilling a 3/4" hole in the top and then reinforcing it, so my choice was an antenna which doesn't need a ground plane. However, they have a different problem.

A metal mass placed near the side of the coil located at the base of such antenna, reduces its performance. So, all the hood, rear door and spare carrier mount ideas were rejected. Besides, you want an antenna as high as possible.

So, this is what came to my mind:

Closer look:

The antenna mount is a Diamond NMO trunk mount, with a trunk bracket removed. The hinge of the mount allows you to fold the antenna down with a few turns of hex wrench, in case you need to park in a garage or go to automatic car wash.

The antenna mount is attached to a GoRhino Rear Liftgate Window Hinge Light Mount. There are two mounts in the kit, so you can use a second one for another antenna. Or for a light, as intended. Or just throw it out, as GoRhino has failed with measurements for a few mils, and one bracket simply didn't fit the passenger side window hinge recess. In this case, just use two fender washers to space the other hinge the same way as the bracket does.

Antenna cable routing is simple: two T grommets from each side, fixed with silicone.

Overall, everything works fine. APRS is working quite good, sometimes hitting digipeaters more than 120 miles away on a medium (10W) power setting. I'll update the post with SWR measurements later.

My next goal is to finish a cover, to really hide the radio and the rigrunner from elements.

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[prerunner1982]

Nice work, definitely a different install than normally seen.

 

[dgriffin1671]

@vap Any updates? Curious what the SWR was

 

[nostatic]

Good timing on the resurrection. Was prototyping a second ham antenna. First is a through-glass Tram mounted on the hard top side window. Works surprisingly well but my SWR was gone up since I originally mounted/checked (now about 1.6:1 at 146mhz). The second mount is a Comet lip mount with a Comet SBB5 dual band. SWR is about 1.1:1 at 144mhz. The CB antenna is about 1.1:1 at 27.160hz. Easy coax route through the firewall plug on the driver's side (if you have an auto trans). Will take some more pics tomorrow but may swap to a Topsy NMO mount with a tri-band (tri-band mostly because that's what I have lying around in NMO

 

[vap]

@vap Any updates? Curious what the SWR was

This is with the spring installed between the antenna and the base, and a little cutting.

2 meters

1.2 meters

70cm

 

[vap]

Works surprisingly well but my SWR was gone up since I originally mounted/checked (now about 1.6:1 at 146mhz).

SWR = 2 is about 10% power loss, SWR 1.6 is only 5%. So you're totally fine here, you will never notice the difference when mobile.

What you should worry most, is not a loss, but rather a radiation pattern. The more omnidirectional it is in the horizontal plane, the better, obviously. That's why any metal mass proximity is an important factor to consider.

Also, in a Wrangler you may often need to shoot your signal to a much higher or lower elevation than usual =) Depending on where you live, it can even make higher gain antenna less preferable choice.

 

[nostatic]

As far as I can figure, Wranglers have a fairly odd ground plane since there is no metal roof or trunk. I can say empirically that the SBB7 outperforms the SBB5 in the same spot (right front fender), and both outperform the Tram 1191 on the rear side window. Typically trying to hit a repeater so a higher take-off angle isn't a bad thing. Top of the antenna for the through-glass is about the same as the SBB7. Not apples to apples, but there are limited spots to put it, and since I'm running three different radios I try to space them out. I also had an issue with LED flickering when transmitting on 2M but I seem to have cleared that with some chokes and moving the antenna back.

Life is an experiment...

 

[Tiderian]

First, the radio mount bracket. Dirt cheap. Easy to DIY. You get the idea.

My goals were to move it away from elements and moving cargo, while keeping the antenna cable short and radio connectors accessible.

The radio is Kenwood D710G, but you can use any hole pattern to mount any radio available.

The power wires, both +12 and ground, goes directly to the battery, through a driver side clutch cable grommet in the firewall. I used 4 AWG marine tinned battery cable to minimize voltage drop, together with marine battery fuses both for ground and +12. Two post marine terminal (as seen on the picture) is used to go from 4 AWG to 10 AWG to RIGrunner.

Now, to the antenna mount.

It is very hard to find a good place for an antenna on a Wrangler. The only way to get a nice symmetrical ground plane at the base of the antenna is to drill a middle of the hard top and glue metal sheets underneath.

I wasn't sure about drilling a 3/4" hole in the top and then reinforcing it, so my choice was an antenna which doesn't need a ground plane. However, they have a different problem.

A metal mass placed near the side of the coil located at the base of such antenna, reduces its performance. So, all the hood, rear door and spare carrier mount ideas were rejected. Besides, you want an antenna as high as possible.

So, this is what came to my mind:

Closer look:

The antenna mount is a Diamond NMO trunk mount, with a trunk bracket removed. The hinge of the mount allows you to fold the antenna down with a few turns of hex wrench, in case you need to park in a garage or go to automatic car wash.

The antenna mount is attached to a GoRhino Rear Liftgate Window Hinge Light Mount. There are two mounts in the kit, so you can use a second one for another antenna. Or for a light, as intended. Or just throw it out, as GoRhino has failed with measurements for a few mils, and one bracket simply didn't fit the passenger side window hinge recess. In this case, just use two fender washers to space the other hinge the same way as the bracket does.

Antenna cable routing is simple: two T grommets from each side, fixed with silicone.

Overall, everything works fine. APRS is working quite good, sometimes hitting digipeaters more than 120 miles away on a medium (10W) power setting. I'll update the post with SWR measurements later.

My next goal is to finish a cover, to really hide the radio and the rigrunner from elements.

Outstanding. I've had similar thoughts about putting the radio in the back to keep the coax short. Considering ordering a metal gate table and mounting a very tiny radio on there, but I'm not committed to it yet.

Great job on this one. Looks great!

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