jj...I know what he's getting at with the Wilson 5000 mag. mount antenna..
The load in the base of that antenna is not that strong, and evedently brittle. I have had two of these antennas. One that was on my burb, the stinger hit a tree limb, and the thing flipped off the back of the Burb, and was hanging by the coax by the rear window's. Stoped the truck, put it back on, but it never worked again! You could shake the thing, and hear the coil rattle around inside it's case.
Second one (which I ran out and bought right after I broke the first one) I was running my 8-pill @ 18v's, and after about a week or two, I lost my ground to the antenna....swr went to hell, thought I had blew a pill, but went to check the swr on the antenna, and it was pegging my MFJ @ around 3.5 (was 1.5)
And found out again....coil had come un-yo-yo'ed inside the base AGAIN! This time, it had never came off....from hitting trees anyway...by the way, if you want that antenna, it's in the bottom of Lake Fork now!
This can not happen to a 10K...and "if" something does get broke on a 10K, It's guaranteed for ever! Is Wilson???