KPA500 Faulting on high SWR on power rise

Your 5KW example is RMS voltage and peak would be 707v. I am not sure how
much moderate SWR effect this value but clearly the 1000v Alpha Delta
discharge tube should be adequate for an Elecraft KPA-500 unless the SWR is
horrible.

John KK9A


From: K4TAX
Date: Sat Feb 24 19:46:55 EST 2018

Based on the specification of 500 volts peak,    5KW at 50 ohms = 500
volts.  It would seem the PL-259 is adequate for ham radio applications
per specification to 0.3 GHZ or 300 MHz without issues.     Of course
one is dealing with 50 ohms, which implies essentially a 1:1 SWR.

73

Bob, K4TAX

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[Don Wilhelm]

While all the "facts" about the voltage ratings of the gas discharge
protectors are correct - that is only true if those devices are new and
have not 'squashed' a number of events.

Please consider that this ham's problem with the Alpha-Delta protector
may be simply that the gas-discharge device in the protector has
absorbed enough energy (both from lightning and from RF) that its rating
is no longer the same as a new one.

Those devices do degrade after a number of "events"-
That is the reason why Alpha-Delta gas discharge devices are replaceable
- they do not last forever.  Some other protection devices do not have
parts that are as easily replaceable, and you have to replace the entire
protector.

73,
Don W3FPR

On 2/25/2018 6:42 PM, [hidden email] wrote:
> Your 5KW example is RMS voltage and peak would be 707v. I am not sure how
> much moderate SWR effect this value but clearly the 1000v Alpha Delta
> discharge tube should be adequate for an Elecraft KPA-500 unless the SWR is
> horrible.
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