Sask_riot, thanks. If I can share some info in my head, I'll be glad to do so. I spent lots of money of several things that simply do not work, but this method is also how the light bulb was invented.
The lower the whip is mounted, the less distance you're going to reach. This is mainly because of signal interruptions, whether it be natural like a mountain or forest, or man made like a building or tunnel. So the trick is to get the whip as high as you can get without destroying your setup. The tallest stock 18 wheeler sits at 13' 6", or about 4.1 meters, so I would suggest that being the tallest you can go with your setup, but unless you want to talk to someone in China (kidding), it's really just funny looking on a regular car.
I overheard a small conversation one day at a CB shop in a truck stop one day, and I remember hearing about the receiver cable/antenna getting the best signal in 3' (.9m) increments. I'm still quoting, this is why you see a majority of coax cables selling in 3' increments (i.e. 3', 6', 18', etc...), and the glass whips have little copper strands spun around them (hence the spiral pattern under the insulation), that all usually end up in 3' increments as well. The size of the whip is not the biggest of deals, but most truck drivers go with the 3' because it won't catch bridges and other things.
If you mount the whip by the rear right tail light while going with a shorter antenna, your signal forward will be sketchy. Raising the height of the whip over the roof of your Riot will allow for slightly better signal, but still sketchy due to signal interference. In my opinion, you want your best signal facing forward and to the left, or toward opposing traffic to those across the pond, so that you can get traffic alerts more clear and quicker from oncoming traffic. It's best to know what you're driving into, and what better way to find out then to ask the ones who have already come from there. If your height was extremely limited, if you didn't it looking all weird, I'd take the same mount and mount it on the inside lip of your passenger side fender. Your ground plane would extend across the hood of your riot and will head in that forward left trajectory, all while keeping the signal interference at a minimum and decreasing your necessary whip clearance height. But it'll look funny...lol
As far as the rubber piece to slip onto your whip, you can do that. It should work fine. Many use tennis balls because it doesn't leave marks on the contact area like a piece of rubber would do. If you have a spring on your whip, try removing it. That makes a slightly longer whip flop around in the wind like no ones business, and on top of that, after a while, snow, rain, mud, water, etc. will get caught up in and around that spring, which will cause rusting, which will also distort your signal.
Hope this info helps...I may not have a lot of free time to post replies and posts, but feel free to bug me if you have any more questions.
P.S.- I love looking at ideas of others. It shows the creativity in the mind of that particular person. There is always a better way to build a mouse trap in my opinion...the trick is, discovering exactly how to build the mouse trap to catch the mouse.
