Am I crazy for wanting to NMO an antenna on the front lip/bulkhead of my truck bed?

[OhSixTJ]

Getting better SWR testing with a mag mount in this location as opposed to my current fender mount so I’m thinking of just drilling it.

I’m getting better SWR readings on the drivers side versus the center.


For reference the vehicle is a jeep gladiator so roof mounts won’t work.

 

[mmckenna]

Probably lots of weird reflections off the steel.

Why would you want to mount it there? For VHF/UHF, that's a pretty poor location with most of the antenna blocked by steel, tinted glass, and if transmitting, way too close to occupants.

 

[OhSixTJ]

Well the top is fiberglass and there’s no roll bar going across the top. As for the tint I don’t think it’s ceramic but I’ll need to check.

Just thought it would be better for radiation pattern with it being in the middle of the vehicle versus the front corner.

 

[mmckenna]

If it was me, I'd take a page of prcguy's book about how to mount antennas on Jeeps. He seems to have it figured out.

I would not, personally, put a transmitting antenna that close to occupants.

 

[OhSixTJ]

If it was me, I'd take a page of prcguy's book about how to mount antennas on Jeeps. He seems to have it figured out.

I would not, personally, put a transmitting antenna that close to occupants.

I tried mounting one just like he has and the SWR was really high on almost all of my antennas including my LarsenNMO270 and comet 2x4SR. Antennas that he had good results with. His hood is steel and mine is aluminum though I don’t think that matters. Maybe it does.

 

[prcguy]

If it was me, I'd take a page of prcguy's book about how to mount antennas on Jeeps. He seems to have it figured out.

I would not, personally, put a transmitting antenna that close to occupants.

I have an NMO mount in the proposed location and it’s working ok for VHF/UHF. Not so great for CB due to the minimal ground plane. I think it’s far enough away from the roll cage and there is not much other metal nearby to mess things up. Driver has to choose what is more important, good radio or good passengers. You probably know my opinion.

 

[OhSixTJ]

I have an NMO mount in the proposed location and it’s working ok for VHF/UHF. Not so great for CB due to the minimal ground plane. I think it’s far enough away from the roll cage and there is not much other metal nearby to mess things up. Driver has to choose what is more important, good radio or good passengers. You probably know my opinion.

Good radio! The kid’s got a thick skull that should shield his brain pretty well.

Joking aside, it’s rare that I have someone in the backseat. I could always forego transmitting when someone is back there.

 

[prcguy]

Good radio! The kid’s got a thick skull that should shield his brain pretty well.

Joking aside, it’s rare that I have someone in the backseat. I could always forego transmitting when someone is back there.

Just keep some aluminum foil handy for passengers.

 

[mmckenna]

Well the top is fiberglass and there’s no roll bar going across the top. As for the tint I don’t think it’s ceramic but I’ll need to check.

Just thought it would be better for radiation pattern with it being in the middle of the vehicle versus the front corner.

OK, I'd trust prcguy on this as he's done the hard work for you.

I'm sure there is some interaction with that C pillar on the drivers side that plays into this, but if it works, it works.

 

[K6GBW]

I believe the Jeep Gladiator uses a lot of aluminum in the body. With something like that a hood mount/NMO combo might be better and easier. The hood mount also has the advantage of being where you can see it when off roading. That reduces the chance of hitting things that will damage it. Just food for thought.

 

[OhSixTJ]

I believe the Jeep Gladiator uses a lot of aluminum in the body. With something like that a hood mount/NMO combo might be better and easier. The hood mount also has the advantage of being where you can see it when off roading. That reduces the chance of hitting things that will damage it. Just food for thought.

I tried it. SWR was not very good. I have a thread on it here: Jeep Gladiator: Trunk lip NMO mount on hood, wonky VNA readings. Can anyone help me understand what I’m seeing?

 

[merlin]

I would not, personally, put a transmitting antenna that close to occupants.

I don't think we are talking 500 watts here, even the 19 inch @100 watt is overkill in my observation.

 

[OhSixTJ]

I don't think we are talking 500 watts here, even the 19 inch @100 watt is overkill in my observation.

It’s 50 watts max at the radio. TX time is seconds at a time, no long-winded QSOs.

 

[K6GBW]

Do you run with the hard top? If so, there is a way to mount an NMO on it, but it's a bit of work. You essentially make a ground plane on the inside of the top and secure it with some sort of adhesive. Then you drill the hole through the ground plane and fiberglass top. They make extra long NMO mounts for such applications. It can be done really professionally, but it does require planning and being very careful.

If this is for a VHF/UHF ham radio I'm wondering why you're SWR was so bad. I've installed a lot of smaller dual band antennas on Jeeps with hood mounts and never had a problem. Perhaps it was a problem with the particular antenna you used. I've used a small Comet B10NMO very successfully on Jeeps. Also, there are two types of "hood" mounts. One slips over the edge of the hood/trunk and tightens dows with Allen screws, the other mounts under the hood. I've used both, but the under hood mount is really easy and when used on the drivers side, about a foot forward of the hinge, it is fine as far as exposure. I had one on my Jeep and ran my radio at 5 watts most of the time. On a few occasions I cranked it up to 15 watts and that was all I ever needed.

 

[OhSixTJ]

Do you run with the hard top? If so, there is a way to mount an NMO on it, but it's a bit of work. You essentially make a ground plane on the inside of the top and secure it with some sort of adhesive. Then you drill the hole through the ground plane and fiberglass top. They make extra long NMO mounts for such applications. It can be done really professionally, but it does require planning and being very careful.

If this is for a VHF/UHF ham radio I'm wondering why you're SWR was so bad. I've installed a lot of smaller dual band antennas on Jeeps with hood mounts and never had a problem. Perhaps it was a problem with the particular antenna you used. I've used a small Comet B10NMO very successfully on Jeeps. Also, there are two types of "hood" mounts. One slips over the edge of the hood/trunk and tightens dows with Allen screws, the other mounts under the hood. I've used both, but the under hood mount is really easy and when used on the drivers side, about a foot forward of the hinge, it is fine as far as exposure. I had one on my Jeep and ran my radio at 5 watts most of the time. On a few occasions I cranked it up to 15 watts and that was all I ever needed.

I bought another one to try in case the first one was bad. It is the lip mount variant. It is odd that my SWR was bad considering prcguy has a similar mount and similar antennas with very good SWR.

I’m curious about the one you mentioned that is a foot forward of the hinge, can you link it?

 

[K6GBW]

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I've run this antenna on four different cars. It's a good antenna that balances convenience with performance.

 

[JustinWHT]

So you have a pickup truck or Jeep?
Is the cab roof metal as most pickup are? What is fiberglass?

 

[prcguy]

I believe the Jeep Gladiator uses a lot of aluminum in the body. With something like that a hood mount/NMO combo might be better and easier. The hood mount also has the advantage of being where you can see it when off roading. That reduces the chance of hitting things that will damage it. Just food for thought.

My Gladiator Mojave is all steel body and hood. Another version might have an aluminum hood, otherwise the rest is steel.

 

[prcguy]

So you have a pickup truck or Jeep?
Is the cab roof metal as most pickup are? What is fiberglass?

The entire top cab on a Gladiator is fiberglass and removable in sections. There is a steel frame around the front window and a steel roll bar above and between the front and rear seats.

 

[JustinWHT]

Friend had a 4 door Jeep with fiberglass shell.
Used a Scotch spray adhesive and aluminum foil, with NMO mount