MFJ-224 Instruction Manual
2-Meter FM Analyzer
1
Introduction
Congratulations on purchasing the MFJ-224 2-Meter FM Analyzer. With this versatile
handheld instrument, you can tune in any signal between 143.5 and 148.5 MHz to
monitor field strength in dBm and FM-deviation in kHz. Accurate tuning is made simple,
thanks to the built-in discriminator-meter
function. Battery status
is also displayed. In
addition to metered functions, the MFJ-224 lets you visually analyze modulation
waveforms and measure instantaneous-peak deviation by plugging into an oscilloscope.
Finally, a headphone monitor circuit helps you tune in and identify signals easily. Before
exploring the MFJ-224's many uses, please take a few minutes to read this manual. A
special orientation section is provided to help you get started.
Technical Specifications
Frequency Coverage.................... 143.5 - 148.5 MHz
Selectivity.................................... -6 dB @ 20 kHz
Receiver Type.............................. Dual Conversion, 10.7 MHz 1st IF, 455 kHz 2nd IF
Oscilloscope Output .................... 1 V p-p for 1-kHz tone at 5-kHz deviation
Phone Jack Output....................... Lo-Z, preset volume level
RSSI Range ................................. -100 dBm to -40 dBm (60-dB range)
Deviation Range......................... 0-7 kHz on Meter, 0-20 kHz on scope (1-kHz tone).
Discriminator Meter Range......... +/- 3 kHz, Zero-centered
Operating Voltage ....................... 6.5 - 9.0 Volts DC
Power Source............................... 9-Volt rectangular alkaline battery
+
-
Frequency
Meter
Power
Monitor
MFJ-224
1
2
3
5
6
7
8
9
1. Power Off/On Switch
2. Power "On" LED
3. Oscilloscope Output (RCA)
4. Headphone Jack (3.5mm)
5. Headphone Monitor "on" switch
6. Meter Function Switch
7. Tuning Knob--Frequency
8. Meter, 3" Precision Movement
9. Antenna Connector (SO-238)
Controls and Jacks
.
Signal
Discriminator
Deviation
Battery
4