MFJ MFJ-213 - Antenna Measurement; Antenna Connector; Swr; Measuring SWR

MFJ-213 HF/VHF/UHF Antenna Analyzer Instruction Manual
6.0 ANTENNA MEASUREMENTS
Excellent tutorials are available in ARRL Handbooks and other League
antenna publications to help you master the art and science of constructing
and adjusting effective antenna systems. Informative introductory material
may also be found on line, but choose carefully. Not all web material is well
edited or accurate (especially items discussed in chat rooms and forums).
Here are some general guidelines to help you get started.
6.1 Antenna Connectors
The MFJ-213 uses a SO-239-female (or UHF) connector. Stacking multiple
adapters together places unnecessary stress the analyzer’s connector and
increases the possibility of measurement error.
6.2SWR
Standing Wave Ratio (SWR), sometimes referred to as VSWR, is the most
widely used format for checking tuning error and impedance mismatch
between antennas and radios. The MFJ-213 is calibrated to work on the 50-
ohm impedance standard used by amateur and commercial two-way
equipment (Zo=50). Unless a different cable impedance is specified by the
antenna designer for matching purposes, always use 50-Ohm cable of known
quality when making up transmission lines and patch cables.
WARNING: Never apply external dc voltages or strong RF signals to the
analyzer’s antenna connector or permanent damage will result. Also,
never connect the output of a transmitter to your analyzer.
6.3 Measuring SWR
Here is the recommended procedure for the checking antenna SWR with the
MFJ-213:
(1.) Turn the unit ON and select the Antenna function (Section-3).
(2.) Select the desired Frequency (Section-4).
(3.) Connect the antenna to the analyzer (Antenna connector)*.
(4.) Rotate the Tune knob to find the lowest SWR reading and write it
down.
(5.) Rotate Tune to either side of minimum SWR and note the 2:1 SWR
points.
*When testing large ungrounded antenna systems such as HF dipoles,
momentarily short the feedline center pin to ground to bleed off static
buildup before connecting to the analyzer.
Version 1 8 © 2012 MFJ Enterprises, Inc