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.pdf
It'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.pdf
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
