On 2/1/11 11:40 AM, Jim Brown wrote:
> On 2/1/2011 10:36 AM, Rick Karlquist wrote:
>> Alternately, you can make these out of "monster" speaker cable
>> or 12 gauge low voltage sprinkler zip cord
>
> One advantage of THHN is that the insulation is rated for 650 volts RMS.
> That yields 1300V between conductors, so the choke will tolerate
> significant SWR. A second advantage is cost -- THHN is really cheap,
> while those exotic speaker cables are wildly overpriced. A third
> advantage is the really nice impedance curve (measured) of the THHN
> chokes (nicer than enameled bifilar, and much nicer than coax). I
> haven't measured a choke wound with exotic speaker cable.
>
And, THHN is good to 90C. I don't know what the speaker wire is good to.
I note that some SPT-2 zipcord is rated to 105C (others are rated to
60C... gotta read the specsheet or markings)
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