MFJ-266C HF/VHF/UHF Antenna Analyzer
Instruction Manual
Version 2A
9
2012 MFJ Enterprises, Inc
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-266C 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-266C 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-266C:
(1.)
Turn the unit
ON
and select the
ANT Analyzer
function (
Section-3
).
(2.) Select the desired
Range
,
Band
, and
Frequency
(
Section-4
).
(3.) Connect the antenna to the analyzer (
Antenna
connector)*.
