Does anyone have any practical experience with an output network for a
transistor KW amp covering 1.8-54 Mhz?
The amp is designed with a 50 ohm drain impedance and I am seeking to
match that to say 10-250 ohms antenna impedance or thereabouts.
I would rather avoid the modern day "traditional" octave low pass
filters plus separate antenna tuner structure commonly employed by
amateur manufacturers as that would take way too many big parts at the KW
level.
My first thought was to use a simple Pi-Net which provides both
matching & harmonic rejection but, the part values turn out to be
cumbersome at a number of points.
My second thought is to use either a Pi-L or a dual Pi-net with the
first section doing a fixed transformation from 50 ohms to the
neighborhood of 500 ohms and the second section transforming down to the
antenna impedance. This will also likely be less confusing to the
autotune algorithm!
A side observation: Did Al Gore invent the Algorithm!? :-)
Anyone care to offer a third thought?
73,
Marv WC6W
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