[UK-CONTEST] ARRL CW

[G3RAU at aol.com]

In a message dated 23/02/2010 13:13:05 GMT Standard Time,  
g3sjj at btinternet.com writes:

I noted  the following were bad - SO4M, YU2A, LZ5R, HG8L, E73W, YT4W, 
RX3APM and  the worst YT40W.

Also very bad clix frrom LZ9W, ET4A and  RK4FWX.





If you seriously and deliberately overdrive a large
 linear several things happen.  Firstly its PSU 
can't cope and starts to distort the output signal 
causing a big increase in hum / ripple, secondly 
the output device(s) are no longer linear due to 
gross overdrive and so heavily flat top, and thirdly 
the mains voltage drops compounding the problem.
  You then have to consider kilowatts of RF
 flowing round the shack getting into everything 
including the transceiver.  This in itself can cause 
some lovely rough notes.  
I think all of that is probably going on in certain 
cases. The trick seems to be to reach your 
licence power limit in the grid of the PA, never 
mind the anode...HI!
 
Derek G3RAU