Does the "Ground Plane" size matter for a VHF Antenna?

[goathearder]

I got my Icom radio all mounted up and I plan to mount the Antenna on a bed rail rack I am making. The rack has a cab high crossbar at the front of the bed so I was going to put a tab on that crossbar for the antenna so I don't have to mess with drilling the roof.

The question is, does the tab need to be a certain size to get the best transmission from the antenna?

Thanks,
John

 

[JJ f150harley]

It shouldn't just make sure to ground the bar and you should be fine.

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[goathearder]

So run some 8 ga from the frame to the bar you think?

 

[Huck]

Depends on the antenna you use. If you use a ground plane antenna it'll suck cause you need 3 sq feet for a proper plane. Use a 1/2 wave or quarter wave. Pm Kanakry he works with that stuff for a living


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[All The Way]

As a Ham I can help ya out too.

If you put the tab at roof height it will work good. 1/4 or 5/8 will work. Don't run a ground wire, its not the same as a ground plane. Grounds, RF & DC Just make the tab big enough so it doesn't break.

In a perfect situation you would want it directly in the center of the roof. Talking with other hams and my own personal experience I've found that some mounting locations you would think should suck actually work really well.

 

[onesickpuppy]

ATW is correct, go with tab large enough for strength and go 5/8 wave and tune for center frequency and you should effectivly double your output due to 3 Db gain.

Lou

 

[goathearder]

Thanks guys. I bought this kit from Outlaw with the permanent mount option:

ICOM F5021 VHF Mobile Radio Chase Pack

So I guess I need to do some research to see what kind of antenna it is. And just to be clear, I don't have to actually ground the rack?

 

[Huck]

Ground plane is not the same as grounding for electronics.

It uses the plane as the surface to broad-cast / receive as a limit. (not the best explanation)

Has nothing to do with a electrical ground per say as you are thinking.

 

[Stepside]

Also, the angle of the ground plane will affect the angle of the transmitted signal.

But, that would be getting a little '****' for practical mobile use.

And, that's from a guy who uses a dual band "thru the windshield" antenna .. but I do have a ground plane on it.

 

[goathearder]

Ok, this is making a lot more sense now.

I come from the world of Rock Crawlers and those guys use CBs so this whole VHF thing is new to me.