Mating a Little Tarheel II antenna with an IC-7100

[WU7X]

I just picked up a Little Tarheel II screwdriver antenna. I am planning on mounting it on the upper light mount on my ARB bumper. The bumper is on my 5th gen 4Runner. Reasoning for that location is that I don't want to drill a hole in the sheetmetal primarily, but also want to have that location as a visual reminder if I'm getting into thick vegetation, etc., and need to dismount it temporarily. I already have a 2m/70 cm antenna mounted on the side of the hood but will probably move it to the driver's side light mount on the bumper. My new radio for working all bands will be an IC-7100. The radio body will be mounted under the passenger front seat and the head on a stalk in front of the dash and beside the passenger's front seat. Hope that wasn't too confusing. I realize that this isn't the best location for the antenna but then most things overlanding end up being compromises.

I'm looking for input on how to ground the engine, doors, hood, exhaust, etc., to minimize RFI. Does anyone have any experience mounting an HF/VHF/UHF radio in a 4Runner or similar vehicle?

 

[Frdmskr]

I just picked up a Little Tarheel II screwdriver antenna. I am planning on mounting it on the upper light mount on my ARB bumper. The bumper is on my 5th gen 4Runner. Reasoning for that location is that I don't want to drill a hole in the sheetmetal primarily, but also want to have that location as a visual reminder if I'm getting into thick vegetation, etc., and need to dismount it temporarily. I already have a 2m/70 cm antenna mounted on the side of the hood but will probably move it to the driver's side light mount on the bumper. My new radio for working all bands will be an IC-7100. The radio body will be mounted under the passenger front seat and the head on a stalk in front of the dash and beside the passenger's front seat. Hope that wasn't too confusing. I realize that this isn't the best location for the antenna but then most things overlanding end up being compromises.

I'm looking for input on how to ground the engine, doors, hood, exhaust, etc., to minimize RFI. Does anyone have any experience mounting an HF/VHF/UHF radio in a 4Runner or similar vehicle?

K0bg.com is your best resource.

I’d rethink the mount. I used to have a Tarheel Model 75 on a bracket mount that was welded and riveted to a Ford Escape. Did it work, yes. Was it structurally stable, absolutely not. I know the Little Tarheel II is lighter but you can’t argue against physics. As you drive the wind pushes the antenna and stinger backwards. That creates pressure against that light mount.

If you really don’t want to do a quarter panel mount (unquestionably the best option) consider either a bull bar mount if you have one (ARB integrates antenna mounting tabs into theirs) or a bigger antenna mounted to a mount off the trailer hitch bars under the rear of the vehicle.


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[PhulesAU]

Check that site. lotsa pics of different mounting set-ups.

 

[WU7X]

Dan,
I think we are on the same page here. This is a pic of my 2000 Tacoma with a Model 100 (?) Tarheel bracket mounted to the steel rear bumper. (I should never have sold that truck!)



Here is how I plan to mount the Little Tarheel II to the front ARB bumper on my 5th gen 4Runner.

 

[Frdmskr]

Dan,
I think we are on the same page here. This is a pic of my 2000 Tacoma with a Model 100 (?) Tarheel bracket mounted to the steel rear bumper. (I should never have sold that truck!)

View attachment 441929

Here is how I plan to mount the Little Tarheel II to the front ARB bumper on my 5th gen 4Runner.

View attachment 441931

View attachment 441932

Ok makes it clearer. I was thinking a rear bumper for some reason.


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[WU7X]

Dan (cont.)

The PO had this Tarheel mounted to the center of his rear hatch using a Diamond K44/3/8C deluxe trunk/hatch mount. I'm taking the guts from that setup and using it on the ARB. The only downside is that the mount insulates the antenna base from being grounded directly to the bumper. I will have to run a heavy duty grounding strap to the point where the bumper bolts directly to the frame of the vehicle. Yes, I know this is not the strongest of mounting systems, but it is the best compromise I can come up with. I was thinking about installing a ball mount on the passenger side at the rear quarter panel up near the roofline, but wonder how well a future owner would appreciate that. This position on the bumper lets me see if the antenna is in any danger of vegetation, etc.

The biggest issue to me is grounding the antenna properly, then bonding the fenders, hood, tailgate, exhaust, etc., to insure minimizing RFI while the engine is running.

Dale

 

[Frdmskr]

Dan (cont.)

The PO had this Tarheel mounted to the center of his rear hatch using a Diamond K44/3/8C deluxe trunk/hatch mount. I'm taking the guts from that setup and using it on the ARB. The only downside is that the mount insulates the antenna base from being grounded directly to the bumper. I will have to run a heavy duty grounding strap to the point where the bumper bolts directly to the frame of the vehicle. Yes, I know this is not the strongest of mounting systems, but it is the best compromise I can come up with. I was thinking about installing a ball mount on the passenger side at the rear quarter panel up near the roofline, but wonder how well a future owner would appreciate that. This position on the bumper lets me see if the antenna is in any danger of vegetation, etc.

The biggest issue to me is grounding the antenna properly, then bonding the fenders, hood, tailgate, exhaust, etc., to insure minimizing RFI while the engine is running.

Dale

If the tab is welded to the bumper no need to run anything to ground the antenna. Just use an insulator to avoid shorting the antenna to the car. Then focus on tying the bumper, frame, muffler and engine into a single circuit. That web page talks a lot about grounding and noise mitigation.


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[WU7X]

If I do go with this installation method, I'll used the driver's side mount on the ARB bumper to install my Diamond NR770HB 2m/70 cm antenna. I will use a new Diamond C101 UHF base connecotr and c110 extension to get the cabling to below the front passenger's seat. I should get a shot of the IC-7100 mounted to show you what that will look like too. Nothing is wired in yet....

Dale

 

[WU7X]

Thanks for your input you guys. I've got that K0BG.com website bookmarked.

Dale

 

[DaveInDenver]

I had an ATAS-120 mounted like that on a bull bar. The brush and vibration were pretty tough on it. Now I know the ATAS is delicate compared to a Tarheel but I'd suggest anything you mount on ARB antenna tab have some flexibility or a shock spring. The bumper and mount won't give and there's a lot of inflexible length in the screwdriver part. If you're lucky just the SO239 shears. It just felt so exposed out there to me but in fairness I never did actually break it. But I ended up taking it off, mobile HF just never really caught on for me. I'm not coordinated enough and, frankly, not a good enough driver to have that much distraction...