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
[email protected]
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