Problems stabilizing a fiberglass rod antenna at highway speeds...

rayra

Expedition Leader
#1
... looking for specific product info or helpful suggestions regarding my problematic antenna install locations

Been trying for a while to find something that might stabilize a rear-bumper-mounted CB/HAM antenna. Using Firestik fiberglass rod antennae, my mounts are on the outer top corners of my rear bumper. Apparently I've got a LOT of wake turbulence back there at anything over 60mph (which leads to other observations about drag and fuel economy). I've tried both with mount spring and without. The only difference is the frequency and intensity with which those 48" antennae attempt to shatter by back window. Tried the tennis ball thing for a while, gyrations became more extreme, the hits harder when they finally happened. Tried a hankerchef and well they don't make them like they used to, I guess. Gave up and took down the antennae.

Then recently I spotted a sort of fin attachment, which I searched for in vain. Antenna (on a jeep) seemed to be wagging a bit but not whipping around like mine. This was on a high spare tire / 3rd brake light sort of mount.

Recently I spotted the contraption in a parking lot and turns out it's a mesh / velcroed / zip up flag flying sleeve, company is ForeverWave.com (no connection). Anyone have any experience with this product in terms of antenna stabilization at highway speeds? Or any othe rhelpful suggestions. Roof or higher mountings are unwanted, I have a couple parking structures in my regular routine and my Suburban barely clears things as it is. As it is now I leave the antennae dismounted and stored in my storage platform / drawers. Rigging them only when I'm 'there' and in a slow-speed environment. I'd like to have good use of the radios in my more usual high-speed driving habit.
 
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#2
Reason it is trying to shatter your rear window is because of lower air pressure or vacuum in the window area. Maybe you should look it doing something about the airflow than something for the antenna. Years ago there were roof air deflectors to direct air downwards across the window.
 

BigSwede

The Credible Hulk
#5
I would just get a different antenna. A base-loaded antenna with a thin stainless whip would have much less cross-section than the fiberglass one. I have had both and there is a dramatic difference in wind resistance.
 
#6
You could build an arm from PVC to mount off the roof rack.
You could then have a bungee cord coming through the pipe to the antenna, that way if would still give if a branch came along the roof but would snap back into it's "mount".
I would of course pad the area where the antenna would contact the mount.

Would look something like this.. (not to scale) and that is a Lego man hand. :ROFLMAO:
large.JPG
 
#7
You could also go with a couple Diamond K9000 motorized antenna mounts and put them on the roof with some base loaded stainless whip antennas.

Or you could build one yourself with a linear actuator and still run the fiberglass antennas.
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