Posted by
Jim Brown-10 on
May 25, 2018; 3:17am
URL: http://elecraft.85.s1.nabble.com/Does-KPA1500-have-these-KPA500-characteristics-tp7641171p7641176.html
On 5/24/2018 7:30 PM, Wes Stewart wrote:
> I haven't measured IMD on my KPA500 either since I don't own two
> generators that are clean enough with the necessary power to do so.
I evaluate IMD by looking at keying sidebands of a long series of dits,
as I posted hear yesterday. Details of the measurement setup and
method, and lots of results, are here.
http://k9yc.com/P3_Spectrum_Measurements.pdfIt's well known that IMD in the K3/K3S increases at rated output, and is
a lot lower at the levels needed to drive a power amp. It takes 25-30W
to drive the KPA500 to full power, and about twice that to drive my Ten
Tec Titans. The K3/K3S is pretty clean at these levels. The plots for
the two amps look almost exactly the same, and have the same shape as
the K3 at those drive levels.In other words, neither amp is increasing
bandwidth. Note that these measurements are of the envelope of peaks, so
they are, in essence, capturing clicks.
IMD also increases with low DC supply voltage. I've not done any
disciplined measurements to put numbers to it, but K6XX has. His data is
in this pdf slide show.
http://k9yc.com/K6XXAmpTalk.pdf73, Jim K9YC
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