height of ant mount and length of whip on pick up

[N4SNO]

I am mounting stainless whip through an ldg tuner. question, If mounted on my tool box I will gain 4 feet in hieght to the feed point and be closer to the tuner.  Is there any advantage to bumper mount it and gain 2 more feet of height using a longer whip. this places the tuner farther away. also I note k0bg states he has a 16 foot whip, can you by extensions for the standerd 102 inch whip? thanks n4sno

[K0BG]

You have a few more things to worry about except the height.

First, unlike the SGC or AH-4 auto-couplers, the LDG will not tune an 8 foot whip 40 through 6. It's advertised range is up to 10:1 VSWR. It will tune it on 6 and 10, perhaps 12, and if the ground loss is high enough, on 15 as well, but that is about it.

Mounting an antenna atop a in-bed tool box is not ideal as it further increases the ground losses which are already high. You'd be better off mounting the whip to the bed rail by using a stake pocket or similar mount.

Here are a couple of suggestions.

I believe it was in the April 2004 issue of QST that Bob Lewis', AA4PB, article appeared. In his case, he was using an SGC couple. In that article, he explains several important considerations, not the least of which is the high voltage which appears at the base of the antenna in such applications. Bob also has a web site with some additional information worth reading. He also has links to a company which sells the mounts and insulators. http://www.ham-kits.com

You might want to visit my web site too. I cover how to properly bond, wire, and some other often over looked aspects of operating mobile. http://www.k0bg.com

Alan, KØBG
www.k0bg.com

[AC2RC]

Alan ,you must live were there's nothing overhead. The max height permitted on the interstate highways is 13.5 '.My 8 1/2' whip in a stake pocket mount on a F150 clears that , no problem and I like the idea of having the mount away from road salt etc....Your website and postings have been very helpful to me in setting up my mobile system, thanks. Yes there are very important details to deal with.