On 11/4/14, 5:38 AM, john@kk9a.com wrote:
Array Solutions mounts their choke in a small plastic Nema junction box.
They use small Teflon coax and I believe it is around a single core in
some of their models. DX Engineering mounts their chokes in a small
aluminum enclosure. Cal-Av mounts theirs in PVC tubing. Is heat a big
concern?
It depends..
I suspect that in most cases there isn't a big problem, because the
antenna and coax layout is reasonably well balanced, so the choke works
effectively and doesn't dissipate much heat.
The vast majority of use by the customers is very low transmit duty
cycle, so the average power is low.
For the 5% (or 1%) of users who run a kilowatt (or more) in a RTTY
contest with the yagi twisted sideways on the tower because of the winds
which are also blowing the coax around, so it's parallel with the driven
element. The choke overheats and fails, and the user goes out and buys
another one and posts a 1/5 review on eham.
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