MFJ-269C Instruction Manual LF/HF/VHF/UHF SWR Analyzer
2
ATTENTION: READ SECTION 2.0 BEFORE ATTEMPTING TO USE
THIS PRODUCT. INCORRECT POWER SUPPLY VOLTAGES OR
EXCESSIVE EXTERNAL VOLTAGES APPLIED TO THE ANTENNA
CONNECTOR WILL DAMAGE THIS UNIT.
1.0 INTRODUCTION
The MFJ-269C is a compact battery powered RF impedance analyzer. It combines five basic circuits; a
variable oscillator, frequency counter, frequency multiplier, 50-ohm RF bridge, twelve-bit A-D converter,
and a microcontroller. Together, these circuits perform a wide variety of useful antenna and RF
impedance measurements including coaxial cable loss and electrical distance to an open or short.
Although mainly designed for analyzing 50-ohm antenna and transmission line systems, the MFJ-269C
also measures RF impedance from a few ohms to several hundred ohms. An easy-to-access user-
controlled Zo setting in the
Advanced
function menus facilitates changing SWR and other SWR
functions (i.e. return loss, reflection coefficient, match efficiency, etc) to any normalized impedance value
between 5 and 600 ohms. The MFJ-269C also functions as a non-precision signal source and frequency
counter. Operating frequency extends from 0.53 to 230 MHz in nine overlapping bands with extended
SWR measurement from 415 to 470 MHz. (LF coverage may be adjusted to cover 0.470 kHz).
1.1 Typical
Use
The MFJ-269C may be used to adjust, test, or measure the following
:
Antennas: ...................................SWR, impedance, reactance, resistance, resonant frequency, and
bandwidth
Antenna tuners: ..........................SWR, bandwidth, frequency
Amplifiers: .................................Input and output matching networks, chokes, suppressors, traps, and
components
Coaxial transmission lines: ........SWR, length, velocity factor, approximate Q and loss, resonant
frequency, and impedance
Filters: ........................................SWR, attenuation, and frequency range
Matching or tuning stubs: ..........SWR, approximate Q, resonant frequency, bandwidth, impedance
Traps: .........................................Resonant frequency and approximate Q
Tuned Circuits:...........................Resonant frequency and approximate Q
Small capacitors: ........................Value and self-resonant frequency
RF chokes and inductors:...........Self-resonant frequency, series resonance, and value
Transmitters and oscillators: ......Frequency
The MFJ-269C measures and directly displays the following:
Electrical length (feet or deg)
Impedance phase angle(degrees)
Resonance (MHz)
Feedline Loss (dB)
Inductance (
μ
H)
Return loss (dB)
Capacitance (pF)
Reactance or X (ohms)
Signal Frequency (MHz)
Impedance or Z magnitude (ohms)
Resistance or R (ohms)
SWR (Zo programmable)