INSTRUCTION MANUAL
C O P YR IG HT 2 010 M FJ EN TE RP RI SE S, INC.
Model MFJ-926B
CAUTION: Read All Instructions Before O perating E quipment
MFJ ENTERPRISES, INC.
VE RS ION 1A
300 Industrial Park Road
S tarkville, M S 39759 USA
Tel: 662-323-5869 Fax: 662-323-6551
C
MFJ-926B HF Automatic Remote Antenna Tuner Instruction Manual
Contents
THE BASICS
Introduction ......................................................................................................................................1
Features ............................................................................................................................................2
Specifications ...................................................................................................................................2
Fast Start...........................................................................................................................................3
Internal Components ........................................................................................................................4
SWR LED ...........................................................................................................................4
TUNE LED .........................................................................................................................4
TUNE Button ......................................................................................................................4
Automatic/Semi-Automatic Tuning Mode.............................................................4
ANT Button.........................................................................................................................5
POWER Button ...................................................................................................................5
Connections......................................................................................................................................5
Transmitter ..........................................................................................................................5
Antenna ...............................................................................................................................5
Ground.................................................................................................................................5
Wire.....................................................................................................................................5
Installation........................................................................................................................................6
MISCELLANEOUS
Antenna Memory..............................................................................................................................7
IntelliTuneTM Algorithm ...................................................................................................................7
LC Limits .........................................................................................................................................7
Morse Code and Flashes...................................................................................................................8
Foldback Circuit...............................................................................................................................8
Grounding Hints...............................................................................................................................9
Antenna System Hints ......................................................................................................................9
Location...............................................................................................................................9
Matching Problems..............................................................................................................9
APPENDICES
Resetting the Tuner ........................................................................................................................11
Factory Defaults ................................................................................................................11
Delete Entire Antenna Memory ........................................................................................12
Delete Antenna Memory Bank..........................................................................................12
Total Reset.........................................................................................................................12
Self Test..........................................................................................................................................13
Power-Down Circuit Test...............................................................................................................14
Relay Test.......................................................................................................................................14
Frequency Counter Calibration ......................................................................................................15
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MFJ-926B HF Automatic Remote Antenna Tuner Instruction Manual
SWR Bridge Calibration.................................................................................................................15
In Case of Difficulty.......................................................................................................................16
Technical Assistance ......................................................................................................................17
List of Accessories .........................................................................................................................17
Limited Warranty ...........................................................................................................................19
FIGURES
Figure 1. Installation Block Diagram ..............................................................................................3
Figure 2. Power-On Operations.....................................................................................................11
TABLES
Table 1. Memory Resolution...........................................................................................................7
Table 2. Tuner Flashes ....................................................................................................................8
Table 3. Failure Messages .............................................................................................................13
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MFJ-926B HF Automatic Remote Antenna Tuner Instruction Manual
The Basics
Introduction
The MFJ-926B HF Automatic Remote Antenna Tuner, the IntelliTunerTM, lets you rapidly tune any
antenna automatically: unbalanced or single-wire. MFJ's exclusive InstantRecallTM, IntelliTuneTM and
AdaptiveSearchTM algorithms give you fast automatic tuning with more than 2500 non-volatile
VirtualAntennaTM memories. .
The tuner includes a highly efficient switching L-network with wide matching capability, 1.8 to 30 MHz
coverage, a radio interface port, and heavy-duty 10 amp/1000 volt relays. It is rated at 200 watts
SSB/CW.
A maximum of 256 values of inductance and 256 values of capacitance are available. With the
capacitance switched between the input and output side, this provides a total of 131,072 L/C tuning
combinations. The nominal tuning ranges are 0 to 24 µH and 0 to 3900 pF.
The MFJ-926B IntelliTuner
minimum SWR and remembers the frequency and tuner settings, safely stored in non-volatile memory.
The next time you operate on that frequency (or close to it), the MFJ-926B tuner settings are instantly
restored and you’re ready to operate in milliseconds.
When you key your transmitter, MFJ’s InstantRecallTM checks its memory to see if you have operated on
that frequency before. If so, tuning is instantaneous and you’re ready to operate. If not, MFJ’s
IntelliTuneTM algorithm (based on MFJ’s famous SWR Analyzer technology) kicks in. It measures the
complex impedance of your antenna. Next, it calculates the components it needs and instantly snaps them
in. Finally, it fine-tunes to minimize SWR, and you’re ready to operate--all in a fraction of a second.
If the antenna impedance is not within the tuner’s measurement range, MFJ’s AdaptiveSearchTM
algorithm goes into action. Frequency is measured and relevant components values are determined. Only
those values are searched for fast tuning. If it still cannot find a match, the search is performed again
using a different search pattern.
The tuners enter a “sleep” mode when idle and when no transmit signal is present, turning off the
microprocessor clock to avoid the generation of spurious signals.
TM
learns and remembers. When you transmit, it automatically adjusts for
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MFJ-926B HF Automatic Remote Antenna Tuner Instruction Manual
Features
• Automatically matches antennas from 6 to 1600 ohms impedance (SWR up to 32:1)
• Handles 200 watts SSB/CW
• Tune in less than 15 seconds, usually less than 5 seconds
• Over 2500 non-volatile memories for tuner settings
• Highly efficient switching L-network matching circuit
• 1.8 to 30 MHz continuous frequency coverage
• Powered by DC voltage impressed on coax using built-in bias tee
• SO-239 coax fed antenna connector
• Connector for random wire or single wire antennas
• Included external bias tee for impressing DC voltage on the input coax
Specifications
• Impedance matching range: 6 to 1600 ohms
• SWR matching range: up to 8:1 for < 50 ohms and up to 32:1 for > 50 ohms
• Minimum power for tuning: 2 watts
• Maximum power while tuning: 100 watts with foldback, 20 watts without foldback
• RF power limit: 200 watts SSB/CW
• Frequency range: 1.8 to 30 MHz continuous coverage
• Capacitance range: 0 to 3961 pF nominal (256 values)
• Inductance range: 0 to 24.86 µH nominal (256 values)
• Relay rating: 10 amp 1000 volts
• Relay electrical life: 100,000 operations
• Relay mechanical life: 10 million operations
• Memory endurance: 1 million erase/write cycles
• Memory data retention: > 200 years
• Power requirements: 12 - 15 volts DC
• External bias tee DC interface: 2.1 × 5.5 mm coaxial plug, center pin positive
• Current consumption: 750 milli-amp or less
• Dimensions (approx.): 10.5 × 2.5 × 14.0 in. (width/height/depth)
• Weight (approx.): 1.0lb
† Specifications and design are subject to change without notice.
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MFJ-926B HF Automatic Remote Antenna Tuner Instruction Manual
DC / RF
RANDOM
Fast Start
WARNING
● Never operate the tuner with its cover removed. Contact with the components inside the
tuner while transmitting will result in painful RF burns.
● Locate the tuner so that the terminals are not accessible during operation. The single wire
connection may have high voltage while transmitting.
● Disconnect all antennas from the tuner during lightning storms.
● Always tune with low power (2-10 watts). Apply maximum power only after tuning up.
● Never exceed tuner specifications.
● Do not transmit with a high SWR for extended periods of time.
1. Connect the transmitter to the “RF IN/OUT” coaxial connector on the MFJ-4117 Bias-Tee
using a 50-ohm coaxial cable. (See Figure 1) This is the RF signal input connector.
2. Connect a 12-15 VDC voltage source capable of supplying at least 750 milli-amps to the “DC
IN\OUT” jack on the MFJ-4117 Bias-Tee. This is your DC voltage input connector.
3. Connect the “RF/DC OUT/IN” coaxial connector on the MFJ-4117 Bias-Tee to the
TRANSMITTER connector on the MFJ-926B Intellituner using 50-ohm coaxial cable. The
MFJ-926B Intellituner will recover the RF and DC signals.
4. Connect your coax-fed antenna to the ANTENNA connector using a 50-ohm coaxial cable, or
connect your random wire to the WIRE binding post.
5. Connect your ground connection to the GROUND post.
6. Key your transmitter to output a carrier of 2-10 watts CW, FM or AM. The SWR should be autotuned to less than 1.5:1. This can be verified with an external SWR meter if desired.
7. You are now ready to transmit at full power.
Note: During the automatic tuning process, the tuner will make some noise. These are the relays
switching at a very high rate and is normal. Do not be alarmed.
12-15
VDC
input
1.8-30 MHz
RF
input
MFJ-4117
Bias Tee
Figure 1: MFJ-926B and MFJ-4117 Installation Block Diagram
Note: To use the Random WIRE binding post, make sure to remove the antenna, if any, from
the ANTENNA connector.
MFJ-926B
ANTENNA
OR
Intellituner
WIRE
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