Need Antenna Ground Plane ideas

[Happy]

I have been using the Comet 2x4SR dual band for many years. Comet designed it for 2 meters thru GMRS.
Comet says it needs a ground plane which is fine for most vehicles. I'm a Little confused as the antenna is 40 inches long and a 1/2 wave 2 meter should be 39 inchs. Anyway, I am trying to have a ground plane.

My question is this: I am wanting to mount this antenna on the spare tire carrier and need ideas about a ground plane. What do you recommend? My mount will be metal with a horizintal top plate for the NMO mount. This plate will be 3 inchs by 3 inchs max. It is bolted to the tailgate.

Any ideas? PS this is a stiff and fairly heavy antenna. This makes me leery of mounting it to the hood. Bronce hood lip seems very flexible and weak for this antenna. The mirror mount position is rated for very low weigh items. The wind drag and wobble of the antenna prevents me from mounting there.

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[chtucker]

I have been using the Comet 2x4SR dual band for many years. Comet designed it for 2 meters thru GMRS.
Comet says it needs a ground plane which is fine for most vehicles. I'm a Little confused as the antenna is 40 inches long and a 1/2 wave 2 meter should be 39 inchs. Anyway, I am trying to have a ground plane.

My question is this: I am wanting to mount this antenna on the spare tire carrier and need ideas about a ground plane. What do you recommend? My mount will be metal with a horizintal top plate for the NMO mount. This plate will be 3 inchs by 3 inchs max. It is bolted to the tailgate.

Any ideas? PS this is a stiff and fairly heavy antenna. This makes me leery of mounting it to the hood. Bronce hood lip seems very flexible and weak for this antenna. The mirror mount position is rated for very low weigh items. The wind drag and wobble of the antenna prevents me from mounting there.

That is a super stiff antenna even with the spring that the SR version has. Have you looked into something shorter/more flexible? Maybe a diplexer and use 1/2 waves on VHF and a second one on UHF

 

[Happy]

Bought the spring as an option about 3 years ago when I first went into a parking garage with my pickup.

Your idea could end up being the solution. With 1/2 wave on 2 meters being 39 inchs I would need something with more flex. The 2X4SR is 40 inches. 1/2 wave UHF is a lot easier.

 

[JakeC]

My mount will be metal with a horizintal top plate for the NMO mount. This plate will be 3 inchs by 3 inchs max. It is bolted to the tailgate.

Is this a DIY solution or something you found? Any pictures?

Just got my MTX275 w/3dB stubby, but also wary of hood damage.

 

[Happy]

My idea is DIY stolen without shame from Mtap.
https://www.bronco6g.com/forum/thre...ve-vhf-gmrs-frs-etc.34238/page-4#post-1146312

Mine is going to be steel 12ga or perhaps 14ga sheeting.
I am going taller to clear the spare tire and using a slightly larger horizontal top platform.
Also planning to use rubber bumpers on the back side and a small piece of paint protection film.

That is a nice radio you have.

 

[Happy]

The Bronco hood and surrounding lip seems too flexible to trust mounting an antenna there. Also the mirror mount location is "maybe" due to the antennas we would want to use. I read that location can hold 7 pounds. But since that location will also be pretty open to tree limbs. I'd hate to rip out a screw mount.

Our radio antenna is mounted to the spare tire carrier. We have decided to try the Larsen NMO2/70B. This is a 1/2 wave antenna so does not require a ground plane. It is reported to have very good SWR across a wide band including 2 meter, 70 cm and GMRS.

The NMO 2/70B antenna will be mounted to the spare tire carrier and since all antennas do better with grounding we ran a wire from the bolts that hold the tire carrier to the tailgate up through the tailgate to a ground on a bolt that holds the hardtop to the body. Our testing shows a solid ground from the NMO mount to the Bronco body. A ground plane is not required but getting as much grounding as you can never hurts. I do not know if this will help with the signal being radiated better or not. I read reports of the antenna being mounted to a UTV roll bar and working well.

Another no-ground plane antenna is the Browning BR-136. Some say it is cheaply made.??
Also the Larsen NMO2/70 SH is reported to work OK with little to no ground plane....but always better with one.

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