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Old June 3rd 09, 09:15 PM posted to rec.radio.amateur.antenna
[email protected] jimp@specsol.spam.sux.com is offline
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First recorded activity by RadioBanter: Jun 2006
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Default Using Tuner to Determine Line Input Impedance

dykesc wrote:
On Jun 3, 1:15Â*pm, wrote:
dykesc wrote:
I am trying to validate impedance values I am measuring with my
MFJ-259B. I want to do this by using my MFJ-993B auto tuner. The tuner
uses a simple L network to create the conjugate match. I want to take
the final inductance, capacitance and swr values from the auto tuner
digital display after matching is completed and back calculate the
impedance that the tuner is seeing. Is there an online calculator that
will do this?


Many thanks for replys.


Wouldn't it be easier and much more accurate to make a known load out of
components close to what the MFJ-259B reads?

It also will be a frequency indepedant "calibration" if you keep the
component leads short.

--
Jim Pennino

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Jim,

I am concerned about an RF field from a local broadcast that may be
causing issues with using the low power MFJ 259B. When I use the auto
tuner I am tuning at 10 watts so plenty to counteract any local rf on
the antenna. I really need to back calculate an impedance from the
inductor, capacitor, and final swr from the auto tuner.


OK, that's a different problem.

Have you concidered this if it is a general problem for you:

http://www.mfjenterprises.com/Produc...ductid=MFJ-731


--
Jim Pennino

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