Re: SWR - does it matter?
Posted by
Elecraft mailing list on
Apr 10, 2019; 2:32pm
URL: http://elecraft.85.s1.nabble.com/SWR-does-it-matter-tp7650791p7650792.html
If you want your antenna match to be correct use aScopeMatch as I describe on my 630M web-site.
Thanks 73 Ken K5DNL
www.k5dnl.com
On Wednesday, April 10, 2019, 9:03:48 AM CDT, Andy Durbin <
[hidden email]> wrote:
As a counter to those who are asserting that SWR 1.5:1 is a good enough match for an antenna system I offer measured data for the KPA500.
At 14.005 MHz my KPA500, when connected to a 1.44:1 SWR load (R37, X9), had a PA dissipation of over 500 watts when producing 400 watts RF output. When the load was changed to 1.30:1 (R39, X3) the PA dissipation was about 410 watts. When the load was changed to SWR 1.07:1 (R49, X3) the PA dissipation was reduced to under 400 watts. (The plots are far more informative than a text description but I can't post them here).
If you don't mind your KPA500 running hot, and are prepared to accept it shutting down with PA DISS fault, then 1.5:1 SWR may be good enough for you. I'd rather know the complex impedance of the antenna system load and avoid loads that result in high PA dissipation.
73,
Andy, k3wyc
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