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MFJ-9402 Instruction Manual
2 Meter SSB Transceiver
INTRODUCTION
Congratulations on your choice of the MFJ-9402. We think you'll enjoy countless hours
rag-chewing, chasing grids, contesting, and roving as you explore the fascinating world of
VHF weak-signal communication. Please read this manual thoroughly before attempting
to operate your unit. Here are some of the radio's features we think you'll like:
Easy to Operate: Just turn on and tune in! No microprocessor mumbo-jumbo to learn,
and no complex commands to memorize.
Potent Signal: Constant Current syllabic speech processing gives your signal 4-6 dB
added punch to break pileups or climb above the noise.
Energy Efficient: All-analog circuitry uses minimal energy. Mountain top and rove on
portable power, or operate from home with a small 2-Amp regulated supply.
Sensitive Receiver: A low-noise front-end and doubly-balanced mixer fight intermod,
yet dig into band noise for weak signals. If the signal's there, you'll hear it!
Excellent Selectivity: Sharper selectivity does make a difference on VHF. Fight contest
QRM and enjoy reduced passband noise with HF-style 2.3 kHz ladder filter.
Real S-Meter: Full-sized electromechanical meter displays subtle changes. Aim your
beam with pin-point accuracy and give out signal reports that mean something!
Agile Tuning: Reduction-drive analog VFO lets you scan for signals quickly, then zero
in smoothly without sudden rate shifts or stair-stepping. Ideal for fast-paced hunt-and-
pounce operation during contests and band openings!
Amplifier Friendly: Built-in FET switch keys solid-state or tube amps. Output signal is
tailored for most popular multi-mode "brick" amplifiers (call 800-647-1800 for the latest
information on Mirage VHF-amplifier products).
Built to Last: Conservative design, premium FR-4 plate-through PC board, state-of-the-
art SMD layout, handsome brushed-aluminum panel, and tough vinyl-clad case make for
good looks and years of dependable service.
Optional MFJ-416 CW Module: Communicate with CW stations instantly--no need to
switch modes, sidebands, or to fiddle with the RIT. Just grab the key and start sending.
A must for snagging elusive grids, extra contest points, or auroral contacts!
At home or on the road, you'll enjoy superb two-meter performance with your MFJ-9402.
Best of all, it's fully backed by MFJ's exclusive NO MATTER WHAT one-year
guarantee. If it breaks, we'll take care of it.
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Related Manuals for MFJ Enterprises MFJ-9402
Summary of Contents for MFJ Enterprises MFJ-9402
- Page 1 A must for snagging elusive grids, extra contest points, or auroral contacts! At home or on the road, you'll enjoy superb two-meter performance with your MFJ-9402. Best of all, it's fully backed by MFJ's exclusive NO MATTER WHAT one-year...
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Page 2: General Description
2 Meter SSB Transceiver GENERAL DESCRIPTION The MFJ-9402 is a compact and economical SSB transceiver designed especially for fixed or portable communication in the weak-signal segment of the two-meter band. Although normally configured for USB voice communication, the MFJ-9402 will also operate on CW with the addition of the MFJ-416 semi-QSK CW-adapter module. - Page 3 • Power Supply: Use any well-regulated 13.8-V DC supply (1.5-amp or greater) or a suitably-rated 14-V battery pack. The MFJ-9402 will also run on 12-volts at slightly reduced RF output. Use a 5.5mm x 2.1 mm coaxial power plug with the + lead attached to the center pin of the connector (use Radio Shack 274-1569).
- Page 4 PEP on SSB (.66 x 150 = 99). In most cases, this will keep your amp linear. The MFJ-9402 is normally adjusted for 7-watts PEP output. While this is right for some amps, it may overdrive others. If so, you may reduce drive by re-setting ALC trimpot R73 for the desired level (R73 is located near the antenna connection on the left-rear corner of the PC board--see Page-9 for trimpot locations).
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Page 5: Front Panel
2 Meter SSB Transceiver voltage and reduce power output. This is normal. Remember, if you overdrive your VHF amp on SSB, the signal won't get any louder--but it's guaranteed to get a lot broader! MFJ-9402 CONTROL LOCATION AND FUNCTION 144.1 144.2... - Page 6 MFJ-9402 Instruction Manual 2 Meter SSB Transceiver TWO-METER ANTENNA SYSTEMS While serious VHF DXers sometimes construct huge antenna systems, it's quite easy to achieve outstanding results with only a modest installation. Here are some tips for selecting antennas and getting top performance from your new VHF-SSB station: •...
- Page 7 MFJ-9402 Instruction Manual 2 Meter SSB Transceiver OPERATING ON TWO METER SSB Unlike the HF amateur bands, there is relatively little atmospheric background noise on 2-meter SSB to cover up extremely weak signals. Because of this benefit, even modestly- equipped stations can expect to communicate routinely over distances ranging from 75 to 150 miles without using repeaters or relying on band openings.
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Page 8: Theory Of Operation
THEORY OF OPERATION General: The MFJ-9402 is a 7-Watt USB voice transceiver covering 144.0-144.3 MHz. CW operation may be added with the addition of the MFJ-416 plug-in CW adapter. Receiver: Bandpass filter L1/L2 pre-selects incoming 144 MHz signals prior to pre- amplification by Q1. - Page 9 POST TRANS DRIVE MFJ-9402 Internal Adjustments: (see pictorial on page 9) [1] Voltage Regulator: Adjust V-REG trimpot for 10.25V on tab of U9 [15]. [2] RSSI Threshold: Adjust AGC trimpot for 4.3 V at RSSI test point [13]. [3] Meter Zero: Adjust M-ZERO trimpot for zero meter reading w/o signal.
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Page 10: Technical Assistance
You can also send questions by mail to MFJ Enterprises, Inc., 300 Industrial Park Road, Starkville, MS 39759; by Facsimile (FAX) to 601-323-6551; or by email to techinfo@mfjenterprises.com. -
Page 11: Troubleshooting Guide
Poor carrier suppression: Connect radio to a dummy load and turn the Mic Gain trimpot (R52) fully off. Monitor your operating frequency with a two-meter receiver- -a FM-HT or scanner will work for checking unmodulated carrier. Key the MFJ-9402 PTT switch carefully adjust Carrier Balance trimpot (R57) for minimum signal in the monitor. - Page 12 MFJ-9402 Instruction Manual 2 Meter SSB Transceiver power supply transformer or electric motor. Move mic away and see if hum disappears. SCHEMATIC...
- Page 13 MFJ-9402 Instruction Manual 2 Meter SSB Transceiver U.S. GRID-LOCATOR MAP...
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