On the Elecraft mailling list, there was a thread recently discussing portable antenna insulators. One guy noted that he scrounges Lexan scraps and makes insulators out of them, to which Mike VP8NO replied,
Seems like overkill to me. By using synthetic “string” to tie off the ends you have all the insulator you need. OTOH I use plastic “corks” from wine bottles on the end of the elevated radials of my 30 metre GP, microwave oven tested naturally. Much more fun to collect than Lexan scraps.
I e-mailed Mike and asked what he meant by “microwave tested.” He answered:
The idea is to test insulators/dielectric material by putting them in the microwave oven along with a mug of water to provide a load. The water should boil but the dielectric under test should stay cool indicating a good low loss rf material. I have noticed a growing take up of plastic “corks” in mid price range wines from VK, ZL, CE and ZS. Never had a bad bottle failure with one. Cork “corks” on the other hand, depending upon quality, have anything up to 5-8% failure rate. I guess not all natural cork is created equal and poor quality just lets air through. Contrary to expectation the UV doesn’t seem to kill them too quickly either.
Makes sense to me. I’ll have to start some of my own, errrrp, research.
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