For the record, here's a Smith Chart that shows in the coloured areas
those impedances which need the so-called "HighZ" L-match configuration:
http://www.karinya.net/g3txq/temp/hiz_loz.png
In the Green area all impedances have a resistive component higher than
50 Ohms; in the Cream area the resistive component is less than 50 Ohms,
but the impedances still require the "HighZ" configuration. By way of
illustration the chart shows how an impedance of 30.4 Ohms (5+j30) at
Point 1 requires the highZ configuration for matching to 50 Ohms.
Not really relevant to the OP's problem, but it's as well to be aware
that the "HighZ" / "LowZ" labelling should not be treated too literally!
Steve G3TXQ
On 08/07/2013 20:42, Richards wrote:
First thing to do is test the antenna with your antenna analyzer to
see if impedance is hither or lower than 50 ohms at the point where
the tuner is. You use information that to select either a LowZ or
HighZ fixed capacitor setting.
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