[Elecraft] KPA500 attenuator rating

[Andy Durbin]

Eric,

I have taken, perhaps obsessive, precautions to ensure that my KPA500 is not damaged by operator error.   I don't expect to ever trip the attenuator in my station.  However, I don't see anything in the documentation that imposes a limit on the amount of time that the KPA500 could be driven with power that trips the attenuator.

As an example - assume 30 W gives 500 W out and the antenna load is well matched.  Now I increase drive to 60 W.  The attenuator trips and the KPA500 is back to 30 W drive and a well matched load.  What causes the firmware to progress to a hard fault to protect the attenuator resistor?

Thanks and 73,
Andy, k3wyc
________________________________
From: Eric Swartz - WA6HHQ, Elecraft <eric at elecraft.com>
Sent: Saturday, August 24, 2019 4:37 PM
To: Andy Durbin <a.durbin at msn.com>
Cc: elecraft at mailman.qth.net <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] KPA-1500 Power Output Variation

The internal attenuator is only rated for short term usage in cases of over drive or high reflected power.  Any hw modification forcing it on will risk damage to the input attenuator components.

73,
Eric
elecraft.com
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