>
>>
>>The opposite example is that I once used Delrin for the PA tuning shaft in
>>a little 6522 2m transmitter. The capacitor rotor was *supposed* to be at
>>RF ground, and that TX couldn't have been putting out more than 25W, tops
>>- but the Delrin melted in seconds. Wrong place, I guess.
>
>Hi, Ian--
>
>Are you SURE that the material was Delrin? Sure sounds like NYLON
>to me. I have been using Delrin as the form for the plate RF choke on
>my 3CPX5000A7 amps at 49 MHz. These run 50-100 KW pulse and
>2 or 3 KW average and often transmit for WEEKS at a time--in some
>cases for YEARS. I have NEVER had a failure of a Delrin RF choke
>or ANY hint of any heating. I have been building these amps--at
>least 100 in the field--for the past 20 years and not one single problem
>with Delrin as the RF choke form.
>
>So I am quite surprised with your results--to the point of believing
>that it was probably NOT Delrin.
>
? Sure, Delrin® has a lower D-factor than Nylon, but it is still
substantial. The styrenes and polyethylenes are way better around RF.
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