[AMRadio] Gates BC250L efficiency

[K9AF at aol.com]

Hello to all
I have  a Gates BC250L AM broadcast transmitter that was recently taken out 
of service.  Before converting it, I fired it up into a dummy load, and 
measured all parameters.  It made a solid 250 watts, as it was intended, and was 
capable of  300 watts or more.   It had approximately 73% efficiency, which 
according to the Gates owner's manual was correct (72 to 75%)    After converting it 
to 160 meters, scaling the components, reneutralizing the finals, and 
retuning it, I can still get 250 watts out with little difficulty, BUT my efficiency 
has dropped to 61%.  I cannot change lead lengths, due to its construction.  
Does anyone have any ideas?  While 61% isn't bad, it's not what I had on the 
broadcast band.   Many thanks.

73

Jerry K9AF