Topband: New MFJ 259C available

Paul Christensen w9ac at
Tue Mar 4 10:25:22 EST 2014

I had a look at the matching Rosenberger calibration standards and for the 
money, the kit is a bargain.  At first, I was disappointed to see what 
amounts to only 1% resistive load accuracy.  The displayed image on the 
website shows a calibration standard that reads about 49.5 ohms.  But, the 
software automatically compensates for the disparity.  It's possible to use 
a DMM with 4-wire resistance capabilities to measure the exact DC resistance 
then enter the value in a table to get excellent operating accuracy, 
certainly better than 0.1%.  Depending on the accuracy needed, the VNWA 
software allows for several other important compensating factors.

My only concern with the VNWA is in its ability to measure Topband antenna 
systems where sweeps are required into the AMBC band.  I'm still looking for 
input from anyone who has made such measurements.

Paul, W9AC 

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