Mike,
Trouble with that is you can't predict which of the 8 capacitors will be
connected. It may be the ones from only one side of the output bus. My
original breadboard, now scrapped, used just one relay per capacitor and I
found that the circuit was badly out of balance when *no* capacitors were
connected ... just the capacitance of the wires running to one side of all
the capacitors was causing it.
The other reason I use two capacitors, one on each end of each capacitor, is
that it puts two sets of relay contacts in series and so divides the voltage
that each switch experiences. I worry about voltage breakdown under high
swr conditions when the voltage node occurs near the tuner and the two
switches in series just doubles the ability of the tuner to survive that
stress.
My antenna is a full wave horizontal loop for 160M which is a very forgiving
antenna to match. I feed it with ladder line and find that with all of that
wire out there the voltages and currents do not seem to build up as badly as
can happen with shorter antennas which are much more of a challenge for a
tuner .. especially when operating at higher power. What works for me may
not work for others.
Don K7FJ
< Don,
< Rather that switching both sides of the caps, what about
alternating which side they are connected to and which side is switched.
That
< should keep things fairly well balanced and cut the relay
count in half.
< 73/72 - Mike WA8BXN
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