GMRS (antenna) mounting idea -- would this work?

[bacon392]

I've toyed with the idea of putting my toll road transponder (EZPASS here in NJ) on top of the A pillar speaker bar yet under my Sky One Touch top.

I think there might actually be enough vertical room for one of the Midland MXTA25 3DB Ghost Antennas under there as well.

Has anyone done this? If it fit, it would be invisible and protected from any external contact. I'm asking because I haven't bought the system yet. Alternatives are hood mounting that antenna or using the bolt hole on top of the Mopar reinforced tire mount with either this antenna or the whip model.

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[ChuckQue]

Paging @CoolTech

 

[Mikester86]

I would not recommend installing a GMRS antenna in the cabin of a vehicle.

 

[Mikester86]

Here is a how to I put together that may be helpful to you in some way. This is for the Midland MXT275 radio and the antenna setup I used.
https://www.jlwranglerforums.com/fo...-2022-jlr-with-automatic-transmission.108333/

 

[TucsonDweller]

I’m tagging in on this as I’d like to hear any expert advice on GMRS antenna mounting. I’m not sure how ground planes do or don’t affect GMRS and these antennas.

I have that antenna as well as the higher gain whip and have it mounted on the cowl. I like the cowl mount, but I’m not sure how it may impact reception. Of note, I also painted the cowl mount, further reducing any potential ground plane gain (if applicable). I’m regretting painting it, but wonder if it would matter anyways.

Op, I know this isn’t the same as your question, but I believe the same principles apply. I would not want to mount the antenna inside, as it would definitely have a negative impact on range because of being inside.

 

[CoolTech]

I think there might actually be enough vertical room for one of the Midland MXTA25 3DB Ghost Antennas under there as well.

Well, "work" is unfortunately kind of subjective. If it will physically fit, it will "work". Much like having a handheld on the inside of your Jeep. If your usage is primarily trail rides and spotting where everyone is in very close proximity of one another, I suppose it will "work" just fine. Now, in terms of range, there a few "rules of thumb" that, as a generalization, will improve your performance. First, getting the antenna as free/clear of obstacles will help. So, moving from the inside of the Jeep to almost anywhere on the outside would be an improvement. Second, as the vehicle permits, locating the antenna near a planar metal surface will help the antenna to form a ground plane. That's why front-mounting often works better in a Jeep where the metal hood can provide a ground plane.... but note that performance direction will be asymmetrical... but, in general still the best location for overall performance. The third rule of thumb is height. GMRS is very strongly line of sight and so the higher your antenna is, the better opportunity you have to receive signals you may not otherwise get. So, this is where mounting a 32" whip higher on the tailgate may also present a viable option.

The good news with the stubby Midland Ghost antenna in conjunction with an NMO mount, it is trivial to swap one antenna for another. On my personal Cherokee, I use the Ghost antenna with a front mount as an "everyday" antenna. When I go 4-wheeling and want maximum performance, I swap on the 6db 32" whip antenna. The swap takes less than 30 seconds.

 

[bacon392]

Thanks for the feedback everyone. Just to be absolutely clear, I am questioning whether it's possible to mount the small antenna on top of the speaker bar, on a metal surface. The rest of the SOT top is fiberglass, with the exception of the motor and the track mechanism, so I do not believe there's material metal obstruction concern there. Additionally, this would be the highest point on the vehicle, save for a whip that extended well above the top of the jeep. Further, I don't quite consider this Inside the Jeep as the only obstruction to clear sky is a fabric top.

What may be problematic is the symmetrical ground plane. The metal upon which I would attempt to mount the stubby antenna is perpendicular to the length of the jeep and is only perhaps 10" wide?

That being said, this solution seems to have less obstruction and more symmetry than mounting an antenna to the tailgate.

It does appear that the GPS antenna and XM antennas are already placed there.

Note: Not my jeep...

 

[TucsonDweller]

Thanks for the feedback everyone. Just to be absolutely clear, I am questioning whether it's possible to mount the small antenna on top of the speaker bar, on a metal surface. The rest of the SOT top is fiberglass, with the exception of the motor and the track mechanism, so I do not believe there's material metal obstruction concern there. Additionally, this would be the highest point on the vehicle, save for a whip that extended well above the top of the jeep. Further, I don't quite consider this Inside the Jeep as the only obstruction to clear sky is a fabric top.

What may be problematic is the symmetrical ground plane. The metal upon which I would attempt to mount the stubby antenna is perpendicular to the length of the jeep and is only perhaps 10" wide?

That being said, this solution seems to have less obstruction and more symmetry than mounting an antenna to the tailgate.

It does appear that the GPS antenna and XM antennas are already placed there.

Note: Not my jeep...

Admittedly, I’m not familiar with the SOT. Though your picture is what I would expect. It there roughly 6” in clearance between the top of the roll bar and the bottom of the top? You definitely don’t want to mount the antenna horizontally.

 

[CoolTech]

’m tagging in on this as I’d like to hear any expert advice on GMRS antenna mounting. I’m not sure how ground planes do or don’t affect GMRS and these antennas.

I have that antenna as well as the higher gain whip and have it mounted on the cowl. I like the cowl mount, but I’m not sure how it may impact reception. Of note, I also painted the cowl mount, further reducing any potential ground plane gain (if applicable). I’m regretting painting it, but wonder if it would matter anyways.

You are correct that ground planes are not AS important in GMRS as they are, for example for the CB frequencies. But, they are still beneficial.

Grounding for an antenna is always achieved at the mount location. The antenna and coax need to achieve a good ground at the point they attach to the mount. As such, the mount itself should be grounded. Antenna mounts that are painted or powdercoated may not achieve the best ground. If you have one of these, it is best that you remove this coating where the antenna attaches to the mount AND where the mount attaches to the vehicle.

 

[TucsonDweller]

You are correct that ground planes are not AS important in GMRS as they are, for example for the CB frequencies. But, they are still beneficial.

Grounding for an antenna is always achieved at the mount location. The antenna and coax need to achieve a good ground at the point they attach to the mount. As such, the mount itself should be grounded. Antenna mounts that are painted or powdercoated may not achieve the best ground. If you have one of these, it is best that you remove this coating where the antenna attaches to the mount AND where the mount attaches to the vehicle.

I was afraid of that. Lol. Thanks for the confirmation about it.

 

[verapx]

Yes I have tried that with a magnetic mount but the reception and transmitting wasn't very good with the top closed. I actually stuck the magnetic ghost antenna on my passenger RSE step between the doors and it worked great. I read somewhere about someone doing that by drilling and mounting the ghost antenna and he said it worked great open or closed but not partially open.

 

[davewald]

The good news with the stubby Midland Ghost antenna in conjunction with an NMO mount, it is trivial to swap one antenna for another. On my personal Cherokee, I use the Ghost antenna with a front mount as an "everyday" antenna. When I go 4-wheeling and want maximum performance, I swap on the 6db 32" whip antenna. The swap takes less than 30 seconds.

That's exactly what I do. Works great. The short antenna is there mostly for looks when I'm just driving around, and I install the whip when offroading.

 

[TucsonDweller]

That's exactly what I do. Works great. The short antenna is there mostly for looks when I'm just driving around, and I install the whip when offroading.

Same. I can still use the radio for most applications, even if it wasn’t planned. But when I’m heading out and know I will be using the radio, I switch to the better whip and it only takes a few seconds.

 

[missionale]

here's how I did mine - wouldn't recommend the antenna within the vehicle structure
https://www.jlwranglerforums.com/forum/threads/mxt275-radio-base-unit-and-a-few-other-things.79181/

 

[nU7OuxIx]

I wouldn't recommend it. Not because it wouldn't physically fit, but because it's possibly unsafe. Not a ham, not a radio person....so interpret the results as you will. With the numbers being thrown, I would be hestitant on mounting something 2 feet away from my head.

https://forums.mygmrs.com/topic/2019-safe-transmission-distance-from-gms-interior-antenna/

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