The Toasted Trap

No it’s not the name of a local breakfast restaurant. It’s the source of quite some antenna work here.

I discovered the problem when chasing 9Q50ON on 17m last December. I narrowed the problem down to either water in the coax or a blown trap. But the antenna worked on 12m and was more or less OK on 30m so I figured it was a trap since a soaked coax would be a problem on all bands. It made sense: 12m = before trap = OK, 17m = trap = bananas, 30m = trap as electrical extension = more or less OK.

A Belgian reader sent me some pictures of his own blown Fritzel traps so I knew what to expect. Two weeks ago I disconnected the antenna and attached a dummy load. The coax tested fine so took the antenna out of the tower. I immediately saw a black powder mark on one of the traps’ weep holes. I sniffed it and my nose got filled with the typical stench of molten plastic. One of the trap’s sealing caps had an extra hole. I took the trap apart and since a picture says more than a thousand words…

This is exactly what the picture of the other ham showed. I wonder what caused the arc. The antenna has been in use since end 2004, and I used it QRO at 500W to 600W since 2005. I still blame the crazy WX the weekend before the toasting. We went from freezing and snow to thaw with rain, and wind in both cases, all within 24 hours. Maybe some moist in the trap? Who knows.

At OptiBeam they try to sell me a 30/40 dual band rotary dipole and a 5 band yagi. That’ll cost me around 2000 Euro. I think this is a fair price for such a setup from a quality brand but will I ever be able to sell the triband yagi? We’ll see how we solve this. I am currently without WARC antenna. Since I don’t have time to play DX anyhow I will limit myself to operating the contests the coming months.

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