That's one way to increase the matching range of the Matchbox. Another
is a variable series capacitor on the input coil or link. Those other
things with the feed line are other details that work to shift the
complex impedance needing matched to one within the range of the tuner.
One could also use an L network to change the impedance in a smaller
space than might be required for adding feedline. Sometimes just a shunt
capacitor is enough, sometimes it take a series capacitor or shunt or
series coils to correct most of the reactance of the load. There are
many ways to solve the obnoxious load problem. Depends on what it is.
One solution probably doesn't work on multiple bands, but it would great
when it does.
73, Jerry, K0CQ
On 2/13/2011 9:35 PM, Denton wrote:
I use a horizontal loop..about 235 ft in length.
My current matchbox has an adjustable tap on the input coil. With a
little tinkering with the input tap, feedline length, feedline width, I
have gotten my matchbox to work 80 thru 10 meters, WARC bands and 60
meters (if 2.25 to 1 swr is acceptable on 60 meters)included.
Quite a bit of work....but to me it was all worth it.
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