MFJ MFJ-249 - Page 4

MFJ-249 SWR Analyzer Instruction Manual
INTRODUCTION
The MFJ-249 SWR Analyzer is an easy to operate, versatile test instrument for analyzing
nearly any 50 ohm RF system on frequencies between |.8 and 170 MHz. In addition the MFJ-
249 can be used as signal source and as an accurate frequency counter.
The MFJ-249 combines four basic circuits; a wide range oscillator, a frequency counter, a 50
ohm RF bridge, and a calibrated bridge unbalance indicator. This combination of circuits».
allows measurement of the SWR (referenced to 50 ohms) c* any load connected to the
ANTENNA connector. The MFJ-249 FREQUENCY switch selects the following frequency
ranges: :
18 - 4 MHz
4 - 10 MHz
10 - 26.2 MHz
26.2 - 62.5 MHz
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113 - 170 MHz
The MFJ-249 can be used to adjust or measure the following:
Antennas: SWR, resonant frequency, bandwidth, efficiency
Antenna tuners: SWR, frequency:
Amplifiers: Input and output networks
Coaxial transmission lines: SWR, velocity factor, losses, resonance
Balanced transmission lines: Impedance, velocity factor, resonance
Matching or tuning stubs: SWR, resonant frequency, bandwidth
Traps: Resonant frequency
Tuned Circuits: Resonant frequency
Small capacitors: Value
RF chokes and inductors: Self resonance, series resonance, value
Transmitters and oscillators: Frequency
The MFJ-249 is also portable. It can be used with either an external low voltage supply, such
the MFJ-1312B AC adapter or with internal AA battery packs.
Warning: Please read this manual thoroughly before using t! s instrument. Failure to follow
the operating instructions may cause false readings or even damage this unit.
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