GMRS antenna question

[FKN Slayer]

I have an nmo mount, magnetic base, low profile antenna. When it was mounted on my Ram roof, reception was perfect. Which mounting location on my Gladiator would most likely be better - on drivers side fender mount or on my Tuwa Pro Moab rack? I might just get another antenna that would work better with the rack if this magnetic mount is crap. I know it needs surface area for optimum performance.

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[Radio Guy]

The top of a bed rack would be higher and better but the antenna needs an adequate ground plane and the top rails on the bed rack don't look large enough. Fortunately a 1/4 wavelength ground plane in all directions around a GMRS antenna is only about 6in, so a 12" dia round disc or square plate would be ideal.

Why not use a permanent NMO mount on a sheet metal ground plane on top of the bed rack and route the coax nice into the cab so you don't have to deal with a mag mount?

 

[JTR178]

This is where mine ended up. Closest thing to a ground plane I could find.

 

[Panthers65]

I've got a trunk lip mount being delivered today. IMO the best looking ones are on the side of the Jeep on the cowl, but those offer the lowest reception. My trunk lip mount will get mounted on the hood near the hinges similar to @JTR178's mount above.

 

[Frank...]

Roof rack works well also.

 

[Radio Guy]

Roof rack works well also.

Not enough ground plane here, plus when you raise the base of the antenna above the sheet metal with that type of mount it changes impedance usually for the worse and further degrades performance. Put just a little sheet metal right under the antenna base like a 6" dia disc and it will be much happier.

 

[FKN Slayer]

The top of a bed rack would be higher and better but the antenna needs an adequate ground plane and the top rails on the bed rack don't look large enough. Fortunately a 1/4 wavelength ground plane in all directions around a GMRS antenna is only about 6in, so a 12" dia round disc or square plate would be ideal.

Why not use a permanent NMO mount on a sheet metal ground plane on top of the bed rack and route the coax nice into the cab so you don't have to deal with a mag mount?

That's probably the route I am going to go. I wasn't sure if the rack rails would provide enough ground plane on their own. Wishful thinking on my part. lol

 

[Kiko]

This is where mine ended up. Closest thing to a ground plane I could find.

This looks real clean. Can you provide a link to the bracke you used? Thanks!

 

[xman1564]

i spent 10 yrs working on radios and installing them off the fender or on the hood is the best option on a gladiator

on the hood for cb nmo mounts as they are longer and hood mounting them is a less likley place to get any tree damage to the antena and still privides a groundplain

 

[xman1564]

This looks real clean. Can you provide a link to the bracke you used? Thanks!

hood is always good place to protect from tree damage and good groundplain?

 

[kb5zcr]

Not enough ground plane here, plus when you raise the base of the antenna above the sheet metal with that type of mount it changes impedance usually for the worse and further degrades performance. Put just a little sheet metal right under the antenna base like a 6" dia disc and it will be much happier.

Radio Guy, I have a question regarding how much ground plane is best VS how much is fine and wouldn't make much of a difference.
The photo of the antenna above on the red crossbar has plenty of counterpoise (as long as its grounded to the crossbar) for a 1/4 wave gmrs antenna.
There are many 1/4 wave whips where the operator attaches a 1/4 wave counterpoise and it works fine. I think in the mobile environment it can't make much difference.
What do you think?

Thanks and 73, Tim

 

[Alpine Warthog]

I've got my midland ghost antenna mounted on the light bar to get it up high. I get good reception, I'm still trying to get a handle on how great transmission is. I got a mile from home through the city (6 and 7 story brick buildings, nothing HUGE, but not houses either) and out to the point the little frs hand held my helper was using got really weak. They said I was still coming in great with just a little static. On the other hand I rarely get responses when on the trail. in, town, I hear random people playing on FRS freqs and nobody responds to radio checks. So I'm not 100% confident I've got good transmission.

 

[Dickster]

I've got my midland ghost antenna mounted on the light bar to get it up high. I get good reception, I'm still trying to get a handle on how great transmission is. I got a mile from home through the city (6 and 7 story brick buildings, nothing HUGE, but not houses either) and out to the point the little frs hand held my helper was using got really weak. They said I was still coming in great with just a little static. On the other hand I rarely get responses when on the trail. in, town, I hear random people playing on FRS freqs and nobody responds to radio checks. So I'm not 100% confident I've got good transmission.

USCG found that LED lights are messing up the frequency of radio. Not saying it is causing your issue because your light isn't on, but if turned on you could lose performance that close.

https://www.windcheckmagazine.com/article/u_s_coast_guard_marine_safety_alert_on_led_lights/

 

[Alpine Warthog]

USCG found that LED lights are messing up the frequency of radio. Not saying it is causing your issue because your light isn't on, but if turned on you could lose performance that close.

https://www.windcheckmagazine.com/article/u_s_coast_guard_marine_safety_alert_on_led_lights/

That's interesting.... I wonder how I can shield it?

I live in PA where you have to keep your lights covered, so I rarely if ever run the darn light bar. (at this point it's a decoration, stupid PA vehicle laws
but I would like to know how to mitigate the interference

 

[tobyw]

Interested in whether or not this passes muster? I made this for the little magnetic mount antenna that came with my Midland radio.

How bad is it?? ?

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