[Elecraft] KPA1500 Power Level

[Bob McGraw]

I've said this for years, even with tube type amplifiers.  One 
exception, to which I'm aware,  is the Johnson Thunderbolt which uses a 
variable L along with variable C for the input components to the Pi L 
network.   Otherwise, the Pi network input circuit is using a fixed 
value of L  and a variable C for the frequency. Thus it is designed to 
match the output device Z only at rated power.

I've performed power measurements on my KPA500 on all bands at 100 
watts, 200, watts, 300 watts, 400 watts, and 500 watts output.  
Measuring input power and output power and calculating efficiency, 
dissipation, and gain on all bands, 160M - 6M.

73

Bob, K4TAX


Message: 5
Date: Thu, 16 Sep 2021 20:26:44 -0400
From: Steve Hall<99sunset at gmail.com>
To:elecraft at mailman.qth.net
Subject: [Elecraft] Subject:  KPA1500 Power Level
Message-ID:
	<CALdUqNPgSbB7ipLRZL8gOYe7FXc1HQWAk-jekiPkKzU1Zrnxew at mail.gmail.com>
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I looked at the link given in part of this discussion regarding efficiency
and dissipated power data at various output levels.  Very revealing.
During a recent virtual hamfest I spoke to the Elecraft designer of the
KPA1500 and he confirmed that the heat dissipated remains nearly unchanged
whether you are running 500 out or 1500 Watts out.  If owners of the
KPA1500 reduce power output to "go easy" on their amp by reducing power,
they are not.