[ARC5] TCS 50-Ohm Matching Configurations.

[David Stinson]

Yesterday, I took a few minutes to test three of 
the suggested capacitive matching methods which 
adapt a 50-Ohm non-reactive load to the output 
of TCS and similar transmitters.  The ARC-2 is 
on the bench and it has an output circuit similar
to the TCS, so used that for the test.  
Can get some time to do this on the TCS 
if anyone is interested.  This wattmeter has not
been calibrated in some time, so take these 
Power readings as relative.

ARC-2 Primary 27V. Dynamotor B+ 
All tests at 3890 KC, tuned for max out.

100 pFd capacitor in series to load.
40 W out.
130 mA PA current.
ARC-2 Ant Tuning 472

1000 pFd ANT to ground.
40 W out.
145 mA PA current.
ARC-2 Ant Tuning 652

Capacitive Divider (TCS tuning box)
270 pFd ANT to Load,
1370 pFd, Load to Ground.
44 W out.
190 mA PA Current.
ARC-2 Ant Tuning 576

"Each to their own," of course.
My preference is to trade 10% of power out
for a 30% reduction in PA current, which is
not only easier on the PA, but makes fully
modulating the rig that much easier as well.

GL OM ES 73 DE Dave AB5S