[Elecraft] KPA-1500 failing on 160...AGAIN!

Jim Brown jim at audiosystemsgroup.com
Fri Sep 27 05:18:01 EDT 2019


On 9/26/2019 10:26 PM, Peter Dougherty wrote:
> Any idea where to start looking here?

What is the antenna? The feedline? Is the antenna resonant? Is there a 
serious common mode choke at the feedpoint? (See 
http://k9yc.com/2018Cookbook.pdf ) Is it matched to the feedline at the 
frequency (ies) where you're trying to use it? How is the feedline 
matched to the KPA? Have you used other high power amps with that 
antenna? Remember that SWR is NOT a descriptor of antenna performance. 
High power can expose antenna and feedline problems that are not evident 
at 100W. Are there elements of the antenna that could be breaking down 
with high power?  Look at coax, connectors, how they are soldered, etc. 
What happens at lower power (500W, for example)?

73, Jim K9YC


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