Ground Plane Whiskers

[K2ZZQ]

I have a pickup truck with an "adventure rack" in the bed of the truck. The top of the rack is sort of like a roll bar 2 or 3 inches behind the cab. I have a 4"x4" tab welded to the bar. My NMO mount for my 2M antenna is mounted to the tab. So I only have a counterpoise toward the roof of the cab.

Question, if I add a few 19" long whiskers, in electrical contact with the tab, and extend them back and to the side, say three or four 10 g copper wires, will that significantly help my TX and receive? Or do I need to do a 19"r plate? I don't want to mount the antenna through the roof even though it would be optimum.
Thanks in advance for any input/ideas.
K2ZZQ
Doug

[WB7X]

If the rack is well grounded to the bed/frame I don't think you will see an appreciable difference. However, it also won't hurt anything to try.

What are you using for an antenna, 1/4, 1/2, or 5/8 wave?

[AC0VH]

It would depend a little on the antenna, I'd guess you /might/ tell a difference with a 1/4w.l. but I doubt it'll make much difference with a 1/2w.l. or 5/8w.l. In fact the 1/2 probably would make zero difference in real performance. Get the mount well grounded to the rack and the rack (and body for that matter) grounded to the frame and it'll be fine. FWIW, if you wanted to do the artificial ground all you'd need is 3 or 4 radials evenly spaced to get the most effect, you wouldn't need a full ~19" circle.

[K2ZZQ]

Thanks for the info. I am running a 5/8 antenna when I am off road. In town I run a 1/4 wave. Not too concerned about in town. Mostly I just "lurk" in town.
This weekend I will work on grounding the truck cab to the frame. Will be in two places. The bed is grounded in two places and it seems that it could be grounded in four. So some work to do. Thanks for all the advice. Great forum! Lots of help all the time.
K2ZZQ
Doug