[Elecraft] Amplifier Thoughts

[K9MA]

On 4/1/2017 09:22, John Perlick wrote:
> In the case of a solid state amp, the output is matched to 50 Ohms or so.  Period.  So any mismatch means that RF is reflected back into the amp....where it is converted into heat.   Depending on your SWR, that could be substantial!  So let's say 3:1. Then 25% of the power is reflected.   Note: at 10:1 you reflect 67% of the power so that means 500 W reaches your antenna and 1000W is dissipated in the Drain-Source junctions of your expensive RF transistors!
Clearly, a practical solid state amplifier capable of tolerating, say, a 
3:1 SWR needs an autotuner.  (Very few of us have the luxury of 
perfectly matched antennas across all bands.)  That said, the autotuner 
should permit maximum flexibility, including multiple settings for the 
same band.  There should also be an easy way to change settings, so the 
amplifier can be easily integrated into the station control system.

73,

Scott  K9MA


-- 
Scott  K9MA

k9ma at sdellington.us