[Elecraft] K3, Elecraft Transverter K144XV-K

[Edward R Cole]

David and Lexa,

My observations on most RF power amplifiers is that gain is higher at 
lower drive levels so proportionally there is more output.  e.g. full 
drive =10w, half drive = 7w, quarter drive = 5w.  So one finds that 
an amplifier hits a minimum output with lowered drive that is not 
linear with change in drive level.  Yet these amplifiers sound fine 
in SSB so must have good linearity.

My 50w 2m transverter actually will produce nearly 60w with 1.5mw 
drive and 35w with 0.73 mw, but minimum output with 0.1mw is about 
15w.  I insert a 3-dB attenuator to get down to 7w output to drive my 
150w amp to 55w which is the drive required for 1400w with my 
2m-8877.  I prefer this arrangement vs running the transverter near 
max at 55w when running digital modes (less heat stress on the 
transverter amp which also translates as less thermal frequency 
drift).  My 25w 1296 transverter runs 20w at full output and about 8w 
with minimum drive.  I've seen this consistently with RF power 
amplifiers (my HF amps operate similarly)

73, Ed - KL7UW
http://www.kl7uw.com
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