Topband: Checking antenna analyzer calibration
w8ji at contesting.com
Fri Sep 29 14:01:56 EDT 2006
Sorry for the delay. After having an operation my up time is
> Putting known values of capacitors, inductors and
> resistors in series or
> parallel combinations across the input would give one a
> specific impedances
> that could be calculated and compared with the MFJ
> measurement. When I
> started this thread I was hoping that the very clever W8JI
> had some really
> elegant [read simple & accurate] method for finding out if
> the instrument is
> reading correctly or needs repair. So far he has been
> silent which I take to
> mean he is busy on other things or he doesn't have my
> desired "quick fix".
To rough check the 259 or 269 you can use a capacitor with
very short leads as well as some resistive loads.
Resistors are actually good enough if you have something as
low as 12.5 ohms and as high as 200 ohms. I use surface
mount resistors soldered right across from the center pin to
the shell of a connector.
Your advice on short leads and known capacitors is good
advice. I would limit lead length to one inch or less. I use
1% tolerance silver mica caps. The analyzer has a mode where
it reads capacitance directly. If that reading is on, any
reactance reading will be on. So save yourself some work and
just directly read the capacitance. The capacitance is
already calculated from the "X " detection.
There is a section on my website
Step six tells you how to get into the calibration mode. It
might take a little practice to rock into the calibrate
(test) mode. You can look directly at the compensated
detector voltage in that mode.
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