Using Tuner to Determine Line Input Impedance
"dykesc" wrote in message
...
On Jun 4, 12:29 pm, "Jerry" wrote:
I may be missing something. But, if the objective it to learn if the
local 105 MHz signal is actually introducing error into your impedance
measurement, only a few Smith Chart Polts are needed. You know the path
(on
the Chart) the shunt reactance will have taken while being adjusted to
make
a "match". You also know the path the series reactance took. Start from
the Chart center and move the impedance along the circles of constant
resistance for the series reactor. Move along the circles of constant
admittance for the shunt reactance. When the Xc and Xl are both known, and
you know which is closest to the "transmitter", it seems that a "program"
is
unnecessary. What am I mising?
Jerry KD6JDJ
Thanks Jerry. No you aren't missing anything other than the fact that
my familiarity with Smith Chart analysis is limited to working through
a few exercises in the last chapter of the ARRL Antenna book. I will
be looking for more Smith Chart tutorial info on the web and am
certain I can get myself up to speed enough to start working with
conductance, suseptance, admittance, etc.
Thanks again. From your post it appears it will be a straight forward
exercise once I get my head around it.
73
Dykes AD5VS
Hi Dykes
As you may already know, the Smith Chart is simply a plot that shows *all*
impedances with a real resistance. Smith displays the impedances so the
user can quickly see how any given impedance can be adjusted by adding any
series or parallel resistances and/or reactances. Series inductance moves
the impedance "upward" along the circles of constant Resistance. Shunt
inductance will move an impedance along the circles of constant conductance.
Jerry KD6JDJ
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