[Amps] Analyzing crossmodulation in PA and antenna system- W8JI suggestions

[Rick Stealey]

This has been an interesting thread, and traditionally a difficult problem 
to isolate but once isolated has straightforward solutions.  Several posters 
have given their experiences and possibilities for correcting the problem.
I am particularly impressed by Tom, W8JI's postings on this problem.  Tom 
outlines a methodical engineering procedure for analyzing the environment in 
which the problem exists and homing in on the problem.  Once isolated the 
fix will be apparent.
>From time to time on other reflectors I will see someone come on and say 
something like, "When I turned on my old TR4 today the fuse blew in the 
power supply. What is the problem."  And he will get a bunch of replies, 
such as "Better change the caps in the PS, replace all the diodes, replace 
the equalizing resistors because they change value, time to replace the 
finals because I had one short out on me once."  Almost never does someone 
suggest a logical method of homing in on the real culprit that caused the 
fuse to blow, to get out the ohmmeter and trace the circuit.  But Tom always 
does, and I REALLY appreciate the advice he gives.  Tom you should write a 
book.  You may not always be 100% right, but 99% is good enough for me.

Rick  K2XT

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