MFJ-266B HF/VHF/UHF Antenna Analyzer
Instruction Manual
2012 MFJ Enterprises, Inc.
Version 1D
9
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-266B uses a type-N female (or NF) connector to ensure
reliable signal connectivity up to 500 MHz. It also comes with a SO-239-
female to N-male (UHF-NM) adapter for transitioning to popular PL-
259 connectors. When purchasing additional adapters, look for N-male
rather than UHF transitions. Stacking multiple adapters together places
unnecessary stress the analyzer’s N connector and increases the
possibility of measurement error. Avoid using PL-259 connectors above
2 Meters because they may contribute significant mismatch to your
measurements. Finally, when installing N-male connectors on patch
cables and feedlines, pay close attention to pin depth. If the tip of the
connector pin extends more than a few mils above the surrounding
contact fingers, the pin shoulder could damage the analyzer's NF
connector.
6.2 SWR
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-266B 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-266B:
(1.) Turn the unit ON and select the ANT Analyzer function (Section-
3).