>AG6K wrote:
>
>> My first experience with the significance of dissipation-factor was when
>> I used a General Radio Co. NYLON double-banana plug at the end of a home
>> made open wire feedline. The nylon melted and began foaming. I changed
>> the plug to one made from phenolic.
The amplifier being used at the time was an SB-220.
>> My second experience was with PVC pipe near the end of a 40m dipole. As
>> I was tuning up a home brew AB1/tetrode amplifier, the telephone rang.
>> My neighbor said: "Rich: your antenna is on fire." My gut feeling was
>> that the presence of flames and smoke indicated that it was quite
>> possibly on fire.
>> - [note: the amplifier was delivering about 1150v peak to the RG9
>> feedline at the time]
>> -Rich-
>
>That's about 8 kW if the line is matched, but of course none of that
>gives us any idea what voltage the delrin or nylon failed at.
>
1150v peak into 50 ohms is not 8kW according to ohm's-law, Mr. Rauch.
>Someone suggested a microwave, but again we would have no idea how
>the material would behave at HF ...snip...
Dissipation-factor in dielectrics increases as frequency increases. I
know of no mateial where the opposite is true. If a plastic does not get
hot at 2400MHz, it is probably going to be ok at 30MHz.
>...snip...
- Rich -
R. L. Measures, 805-386-3734, AG6K
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