[Elecraft] KPA500 High Reflected Power Fault

[Mike WA8BXN]

If a tuner gets you to a good match at low power where there is a balun
involved, but you run into problems at high power, I would first suspect
that the balun is getting saturated. Using a balun between an antenna and
the tuner many times is not a good thing to do. Using a balanced line tuner
is really the best thing to do. Changing the length of feedline from antenna
to balun does change the impedance that the balun or tuner has to deal with.
And that chance can help at a specific frequency that has problems. 
 
Using a single antenna on multiple bands is very attractive. Unfortunately
it is sometimes not an easy thing to do efficiently. In most cases antennas
are always a tradeoff. There are so many constraints we deal with. Lot sizes
 deed restrictions, supports available, how much we can spend. You want a
great antenna system and unlimited budget? I'm sure someone can sell you the
land needed, someone can clear it, someone can put up multiple support
structures and good antennas for the bands of interest. 
 
Most often what we wind up with is a compromise in one way or another. In
many cases that compromise, with careful study and understanding, can result
in a quite respectable antenna. The other trade off to consider is the time
spent in getting the best antenna versus getting on the air a lot with a
variety of antennas (or maybe just one). 
 
I must confess that I probably spend more time brooding over what could be a
better antenna than getting on the air and making contacts with the fairly
decent antennas that I do have here. 
 
73 - Mike WA8BXN