[AMPS] Big Amps and Antennas

[Bruce Plantin]

Hello,
Since starting to use my "big boy" amp, I have had more antenna problems than in all my 40 years + of ham radio.
Examples:
1. Those cheap black plastic insulators commonly sold at hamfests melt. The result is the antenna falls.
2. A small tree branch (1/4" dia.) fell from a tree and was hanging from the end of the antenna (I just happened to notice this). The first time I put power to the antenna, the 12ga stranded copper wire melted at that point and the antenna fell down. I found the small branch on the ground and it showed signs of having been  on fire.
3. The latest happening is the strangest (I swear it is true). After tuning up the amp into a dummy load, I switched to the antenna to fine tune the amp settings. While fine tuning, everything looked normal then all of a sudden, all the amp meters went wild. My first thought was "damn, one of those paracites, how will I ever get rid of it". Then I went back to the dummy load, and every thing was back to normal. I immediately went out into the yard and found the antenna on the ground. The 12" by 1" ceramic end insulator was broken at the antenna end. I could not visually find any defects in the insulator at the failure point.

Is all this being caused by corona effects? What could be the max voltage at the antenna ends? Copperweld appears to be the only way to go for wire, but what should I be using for end insulators?
Any insight would be greatly appreciated.

Bruce,
W3BP



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