Re: KPA-1500 on digital modes

Posted by Roger D Johnson on Aug 29, 2019; 1:03pm
URL: http://elecraft.85.s1.nabble.com/KPA-1500-on-digital-modes-tp7654828p7654833.html

It's interesting that the heat that has to be dissipated is pretty close
to 1000 watts in all these scenarios! Running the amp at less than full
power buys you nothing.

73, Roger


On 8/29/2019 8:38 AM, Larry (K8UT) wrote:

> Pete,
>
> I don't run my amp at full legal limit on digital modes, but typically set the
> input power for about 1000 watts output. One of the interesting characteristics
> of the amp is increased efficiency as power increases. At 600 watts efficiency
> is only 38%, whereas at 1000 efficiency increases to 50% and at 1500 watts to 60%.
>
> (see screenshots)
>
>   -larry (K8UT)
>
> ------ Original Message ------
> From: "N4ZR" <[hidden email]>
> To: "Elecraft List" <[hidden email]>
> Sent: 2019-08-29 07:59:23
> Subject: [Elecraft] KPA-1500 on digital modes
>
>> Elecraft's published specs rate the KPA-1500 for 1500 watts output on all
>> modes.  In prepping for this weekend's contest, I've been running it at closer
>> to 700 watts, because I've found that even just running on CW, with its much
>> lower duty cycle, my amp reaches 70C quickly.  I don't do that much digital
>> contesting, though, so I'm wondering whether 1500 watts output is on digital
>> modes is realistic or a recipe for trouble.
>>
>> --
>> 73, Pete N4ZR
>> Check out the Reverse Beacon Network
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>>
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