laird b4503 gmrs antenna

[wpwx694]

I'm thinking about installing it on the hood of my gmc pick up truck, will it be good on swr and will it get good reception for repeaters at that location?
I don't want to drill a hole on the top of the roof.

Or on the back of the cab like this




Something like this I found on the internet.

See pictures below

 

[JamesWest]

i have had antennas in all of those locations. worked fine. but the best location is in the center of the roof of the vehicle, drilling a hole or using a mag mount. but hardly anyone does that unless they are not married. back of the cab photo looks best of these examples.

 

[mmckenna]

That is a 5/8th's wave antenna, and it will want a ground plane under it if you want it to work well. Mounting it off the back of the cab might make tuning for low SWR difficult. It'll also be directional towards the rear of the truck, which may not work in your favor.

Mounting it on the front fender is going to have the same challenge, and it'll put it below the cab, which will likely make the directivity of it even worse.

Using the 90º bracket on the back of the truck is going to require drilling holes, so might as well just do it right. I know it's a hard decision, but it really is worth it. Putting a good antenna like that on the center of the roof is going to make it a good performer.

If you are really dead set against drilling a hole in the roof, there are companies that make mounts that go in the center brake light that can be a better option in some cases. They do have some issues with leakage, so use accordingly.

 

[wpwx694]

That is a 5/8th's wave antenna, and it will want a ground plane under it if you want it to work well. Mounting it off the back of the cab might make tuning for low SWR difficult. It'll also be directional towards the rear of the truck, which may not work in your favor.

Mounting it on the front fender is going to have the same challenge, and it'll put it below the cab, which will likely make the directivity of it even worse.

Using the 90º bracket on the back of the truck is going to require drilling holes, so might as well just do it right. I know it's a hard decision, but it really is worth it. Putting a good antenna like that on the center of the roof is going to make it a good performer.

If you are really dead set against drilling a hole in the roof, there are companies that make mounts that go in the center brake light that can be a better option in some cases. They do have some issues with leakage, so use accordingly.

Would just using nmo mag mount work if it's in the middle of the roof with b4503

 

[mmckenna]

Would just using nmo mag mount work if it's in the middle of the roof with b4503

Of your options, the magnetic mount center of the roof is going to work better.

Long term, magnet mounts can cause paint damage. And you have to consider how you get the coaxial cable into the cab. Running coax through a window/door is going to damage the cable over time.

 

[speedway_navigator]

It'll also be directional towards the rear of the truck,

It would be interesting to see the radiation pattern since the roof ground plane is at the antenna base vs the larger bed about 2 wavelengths below.
I expect it would be a figure 8 with one lobe larger than the other, but which one?

 

[speedway_navigator]

ps I wonder how much attenuation wpwx694 gets from hairy forearms...

 

[AK9R]

ps I wonder how much attenuation wpwx694 gets from hairy forearms...

Looks like they are below the likely radiation pattern of the antenna.

 

[steve9570]

I have the one in your 2nd picture the Tram it works great. its on a drunk lip mount.
No problems going thru car washes etc.

 

[KOK5CY]

I'm using a tram nmo magnet mount with a nmo 450.5/8 wave over 5/8 wave dead center of the roof .

 

[madrabbitt]

I have a fender mount, vehicle specific on my 2016. Its on a CB, and ground plane on that is a completely different issue.

I also have a 3rd brake light mount on the truck. Thats my "i'm going to use this for a bunch of crap" antenna mount and not permanently on any equipment.

Stupidly expensive but good quality. Zero issues with leakage from the brand i bought, it comes with appropreate gasket material on the cab side, and the 3rd brake light seals to it well.

 

[madrabbitt]

photos of both the 3rd brake mount and the fender mount in this thread