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MFJ-994B IntelliTuner Automatic Antenna Tuner 

Instruction Manual 

 

©

 2004-2010 MFJ Enterprises, Inc.

 

16

Meter Needle Bounce Codes 

(Meter needles bounce to the indicated mark until buttons are released.) 

 

Forward 

30 Watts Mark 

100 Watts Mark 

300 Watts Mark 

 Capacitor 

Switches To 

Transmitter Side 

Insufficient Power to 

Tune 

(Forward < 2 Watts) 

Power Too High to Tune 

(Forward > 125 Watts, or 

Forward > 75 Watts and SWR > 3) 

Reflected 

5 Watts Mark 

20 Watts Mark 

60 Watts Mark 

 Capacitor 

Switches To 

Antenna Side 

Bypass Mode 

(L = 0 and C = 0) 

L or C at Its Limit 

During 

Manual Adjustment 

Both Needles 

30/5 Marks 

100/20 Marks 

300/60 Marks 

 

Not Used 

Not Used 

Power Overload 

(Forward > 600 Watts) 

 

Table 3.  Meter Needle Bounce Codes. 

 
 

Transceiver Foldback 

 
Modern transceivers with solid-state finals usually have a foldback circuit to protect the final transistors 
from damage due to high SWR.  A foldback circuit detects the SWR during transmit and reduces the 
output power as the SWR rises above a preset threshold, usually 2:1.  The higher the SWR, the lower the 
power is set to prevent damage. 
 
If your transceiver has a foldback circuit, you can simply key down and tune at any power level from 2 to 
100 watts.  If your transceiver does not have a foldback circuit, you must manually set the power level to 
20 watts or less for tuning.  At higher power levels, the reflected power occurred during tuning can 
damage your transceiver or amplifier and causes component arcing which can damage the relays in the 
tuner. 
 
Check your transceiver owner's manual to see if it has a foldback circuit.  When an amplifier is used, the 
amplifier must be bypassed during tuning. 
 

Note:  MFJ recommends that a transceiver-specific interface cable be used between the MFJ-994B 

and your transceiver to ensure that tuning only occurs at low power. 

 
 

Grounding Hints 

 
To minimize RFI, single wire feedlines (such as used with Windom or longwire antennas) should be kept 
away from other wiring.  Radiation will be minimized if the single wire feeder runs parallel and 
reasonably close to the wire that connects the tuner to the outdoor ground.  The antenna feed wire should 
be adequately insulated to prevent arcing or accidental contact. 
 
 
 
 
 

Summary of Contents for IntelliTuner -994B

Page 1: ...ctions Before Operating Equipment MFJ ENTERPRISES INC 300 Industrial Park Road Starkville MS 39759 USA Tel 662 323 5869 Fax 662 323 6551 COPYRIGHT 2005 2010 MFJ ENTERPRISES INC C Model MFJ 994B VERSION 2A IntelliTuner Automatic Antenna Tuner TM ...

Page 2: ...itional handbooks or other official publications The copy of this manual provided to the customer will not be updated to reflect current data Customers using this manual should report errors or omissions recommendations for improvements or other comments to MFJ Enterprises 300 Industrial Park Road Starkville MS 39759 Phone 662 323 5869 FAX 662 323 6551 Business hours M F 8 4 30 CST ...

Page 3: ...UTO Button 5 TUNE Button 5 StickyTune 5 POWER Button 6 Back Panel 7 Power 7 Remote Port 7 Radio Interface 7 Transmitter 10 Ground 10 Wire 10 Antenna 10 Installation 10 SWR Wattmeter 11 SETUP Target SWR 12 Auto Tune SWR 12 Antenna Memory 12 Meter Range 13 OPERATION Manual Tuning 14 Component Limit 14 Tuner Status Indicators 15 Transceiver Foldback 16 Grounding Hints 16 Antenna System Hints 17 Coaxi...

Page 4: ...for FT 100 28 Connections for FT 450 29 Operation for FT 450 29 Connections for FT 857 or FT 897 30 Operation for FT 857 or FT 897 30 Connections for FT 950 31 Operation for FT 950 31 Yaesu Radio Interface MFJ 5124Y2 32 Connections for FT 847 32 Operation for FT 847 32 Yaesu Radio Interface MFJ 5124Y3 33 Connections for FT 1000MP series of radios 33 Operation for FT 1000MP series of radios 33 Conn...

Page 5: ...ack Panel 7 Figure 5 Alinco Interface Cable 8 Figure 6 Icom Interface Cable 8 Figure 7 Yaesu Interface Cable MP 2000 9000 series 9 Figure 8 Yaesu Interface Cable FT 2000 series 9 Figure 9 SWR Wattmeter 11 Figure 10 Power On Operations 19 Figure 11 MFJ 994B Circuit Block Diagram 37 TABLES Table 1 Antenna Memory Resolution 13 Table 2 Meter Needle Stationary Codes 15 Table 3 Meter Needle Bounce Codes...

Page 6: ...MFJ 994B IntelliTuner Automatic Antenna Tuner Instruction Manual 2004 2010 MFJ Enterprises Inc iv THIS PAGE IS LEFT BLANK INTENTIONALLY ...

Page 7: ...tings are instantly restored and you re ready to operate in milliseconds There are four banks of memory which can learn and remember more than 2500 frequencies and tuner settings per bank 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 algo...

Page 8: ...ng values SO 239 coax fed antenna connector Connector for random wire or single wire antennas Optional remote control Optional radio interface cables for compatible radios Specifications Impedance matching range 12 to 800 ohms SWR matching range Up to 4 1 for 50 ohms and up to 16 1 for 50 ohms Minimum power for tuning 2 watts optimum SWR tuning accuracy occurs at 10 20 watts Maximum power while tu...

Page 9: ...i automatic unless a compatible radio interface cable is connected between the MFJ 994B and your transceiver This ensures that the MFJ 994B does not attempt tuning during high power operation and is particularly important when an HF amplifier is in line Note If an amplifier is in line it should always be bypassed prior to tuning 7 Key your transmitter to output a carrier of 2 20 watts CW FM or AM ...

Page 10: ...00 Watts SSB CW MFJ IntelliTunerTM 0 1 0 3 0 50 100 200 300 0 5 20 40 60 8 5 0 3 0 2 0 1 5 1 2 Hi x1 Lo x 1 400 3083 1 10 BYPASS Z Figure 2 MFJ 994B Front Panel SWR Wattmeter The cross needle meter measures forward power reflected power and SWR It operates whenever the MFJ 994B is powered on The default full scale readings are 3000 watts forward and 600 watts reflected power The meter can be set t...

Page 11: ... is especially important when an HF power amplifier is in line Note If an amplifier is in line it should always be bypassed prior to tuning TUNE Button Has three different functions based on the length of time you press and hold it before releasing Press TUNE quickly less than 0 5 second to bypass the tuner RF from the transmitter goes directly to the antenna with no matching Press and hold TUNE f...

Page 12: ... UP C DN Press to switch the capacitor between the input and output side Press to bypass the antenna tuner Press to cycle the Auto Tune SWR among 0 5 1 0 and 1 5 above the target SWR Press to toggle the Target SWR between 1 5 and 2 0 Press to cycle the Memory among banks A B C and D Press to cycle the Meter Range among 300 watts 3000 watts and auto range Press to increase both capacitance and indu...

Page 13: ... lights to indicate tuning is in progress and the green SWR LED lights when the SWR is below the target SWR Note To use the MFJ 994RC remote control the AUTO button on the MFJ 994B automatic tuner must be locked in otherwise Automatic mode is selected Radio Interface A 3 5 mm stereo phone jack for connecting to the tuner interface connector of compatible radios Most radios provide 13 8 VDC power t...

Page 14: ...tton for two seconds to start the tuning process Push TUNER quickly to bypass the tuner Refer to Icom Radio Interface on page 26 for connections and operation Pin Key connects to Pin Start connects to Pin Ground connects to 2 Pin 3 13 8V connects to 4 1 the Tip of 3 5 mm Stereo Phone Plug the Ring of 3 5 mm Stereo Phone Plug the Center Pin of Power Plug the Sleeves of both 3 5 mm Stereo Phone Plug...

Page 15: ...ne process when an amplifier is not used For best accuracy when an amplifier is used MFJ recommends that the Yaesu CW tune setting be set to 50 watts for 100 watt transceivers and 75 watts for 200 watt MKV transceivers during the tune process If a FH 1 or FH 2 keypad is also used both the FH 1 FH 2 and the radio control cable may be plugged in parallel using a 3 5 mm headphone splitter mono or ste...

Page 16: ...hile transmitting Disconnect all antennas from the tuner during lightning storms Always tune with low power 2 20 watts and any in line amplifier must be bypassed Apply maximum power only after tuning up Never exceed tuner specifications 1 Place the tuner in a convenient location at the operating position When using a random wire antenna the feed through insulator can have high RF voltage This volt...

Page 17: ...0 watts and reflected power less than 40 watts automatically set the meter to the low power range To cycle the meter range among low high and auto range press the TUNE and L DN buttons simultaneously The forward needle will read 300 for high range 30 for low range and 100 for auto range until the buttons are released SWR is calculated from the forward and reflected power measurements as shown by t...

Page 18: ...ge Auto Tune SWR You can set the SWR threshold to 0 5 1 0 or 1 5 The default is 0 5 In the automatic mode the tuning process will automatically start when the SWR is above the target SWR by this amount of SWR threshold For example for target SWR of 1 5 and auto tune SWR of 0 5 the tuning process will start whenever the SWR rises above 2 0 1 5 0 5 and there is at least two watts of RF power applied...

Page 19: ...riangle asking you to confirm the deletion Press C UP to confirm delete both meter needles will read full scale or press L UP to cancel the antenna memory delete both meter needles will read zero Total Reset erases the antenna memory and returns all tuner settings to their factory default states To achieve this turn power off press and hold TUNE L DN and C DN while turning on the power Both meter ...

Page 20: ...eedle will bounce to 5 watt mark Press C UP and C DN simultaneously again to return the capacitance to the transmitter side and the forward needle will bounce to 30 watt mark to indicate the change A general rule of thumb is that loads with impedance higher than 50 ohms call for the capacitance on the antenna side loads lower than 50 ohms call for the capacitance on the transmitter side Pressing C...

Page 21: ...eedle will bounce to full scale This occurs when the forward power exceeds 75 watts and the SWR is greater than 3 0 or when the forward power exceeds 125 watts regardless of the SWR If more than 600 watts is applied to the tuner the tuner will go into bypass mode and both Forward and Reflected meter needles will bounce to full scale If the tuner cannot achieve the target SWR the Reflected Power ne...

Page 22: ...sually 2 1 The higher the SWR the lower the power is set to prevent damage If your transceiver has a foldback circuit you can simply key down and tune at any power level from 2 to 100 watts If your transceiver does not have a foldback circuit you must manually set the power level to 20 watts or less for tuning At higher power levels the reflected power occurred during tuning can damage your transc...

Page 23: ...nd leads for RF and lightning should have wide smooth surfaces Avoid the use of woven or braided conductors in RF and lightning grounds unless the lead needs to be flexible Antenna System Hints Coaxial Cable Selection The proper selection of coax cable will minimize antenna system losses especially in the presence of high SWR And the coax cable selection is particularly important in high power ama...

Page 24: ...several thousand volts This can cause component arcing and heating The following suggestions will reduce the difficulty in matching an antenna with a tuner Never center feed a half wave multi band antenna with a high impedance feedline that is close to an odd multiple of a quarter wave long Never center feed a full wave antenna with a feedline close to a multiple of a half wave long If this tuner ...

Page 25: ...is off before performing any of the following power on operations Firmware Version Number Make sure the meter is calibrated To obtain the firmware version number press and hold the C UP button while turning the power on The version number X YY is represented by the meter forward needle for X forward reading 10 and the reflected needle for YY reflected reading For example forward needle on 20 watt ...

Page 26: ...ly try resetting the tuner to factory defaults Delete Antenna Memory To delete the antenna memory turn off power to the tuner and then press and hold both the TUNE and C DN buttons while turning the power back on Both meter needles will read half scale Press the C UP button to delete the antenna memory both meter needles go to full scale or press the L UP button to cancel both meter needles go to ...

Page 27: ...le and then drops to zero followed by the reflected needle going up slowly to full scale and then dropping to zero This tests the meter Release the L UP button before the reflected needle goes to zero 6 The reflected needle goes to the 3 watt mark Now press each of the front panel buttons in this sequence C UP C DN L UP L DN AUTO and then TUNE The forward needle should bounce once for each press a...

Page 28: ...needle will read 40 per Table 3 above 8 Turn the power off Relay Test WARNING Turn off the transmitter power or disconnect the transmitter before performing this test otherwise damage to the tuner can result To test the relays and their control circuitry press and hold the C DN button while turning the power on Both meter needles will bounce Release the button The relays are tested in groups of fo...

Page 29: ...resume normal operation 8 Turn off the tuner power and secure the cover back onto the tuner Frequency Counter Calibration To calibrate the frequency counter you will need a transmitter a 50 ohm dummy load two 50 ohm SO 239 coax cables a Phillips screwdriver and a tuning tool or small flat blade screwdriver WARNING Do not touch anything inside the tuner during operation Serious painful RF burns can...

Page 30: ... middle of an HF band such as 7 253 MHz for calibration 5 Press and hold both the C UP and L UP buttons while turning the tuner power on Both meter needles will bounce Release the buttons 6 Key the transmitter to output 100 watts and adjust the trimmer capacitor C91 for minimum reflected power Notice the reflected meter movement is exaggerated for easier calibration 7 Key the transmitter to 100 wa...

Page 31: ...ned off The radio does not fuse the DC power to the tuner and damage to the radio can occur if the interface s power connection comes in contact with ground 4 Connect the 5 pin molex connector to the mating 5 pin molex connector marked as ACC on the back of the Alinco radio 5 Push the POWER button on the tuner to the in position and then power on the radio Operation The operation of the MFJ 5124A ...

Page 32: ...NER on the back of the Icom radio 5 Push the POWER button on the tuner to the in position and then power on the radio 6 Some Icom radios such as the IC 706 automatically check to see if an external antenna tuner is connected during power on For other Icom radios such as the IC 718 the Tuner Type menu in the radio menu system must be enabled Refer to your radio s operating manual for accessing the ...

Page 33: ...or ACC on the back of the Kenwood radio 6 Push the POWER button on the tuner to the in position and then power on the radio 7 Some Kenwood radios automatically check to see if an external antenna tuner is connected during power on For other Kenwood radios such as the TS 450S and the TS 690S the External Antenna Tuner menu in the radio menu system must be enabled Refer to your radio s operating man...

Page 34: ...r s RADIO INTERFACE jack 4 Insert the 2 1 x 5 5 mm coaxial power plug into the tuner s POWER jack 5 Insert the 8 pin modular plug into the MFJ 5124 s TO RADIO jack 6 Important Make sure the DC power to the radio has been turned off The radio does not fuse the DC power to the tuner and damage to the radio can occur if the interface s power connection comes in contact with ground 7 Connect the 8 pin...

Page 35: ...mage to the radio can occur if the interface s power connection comes in contact with ground 7 Connect the 8 pin mini DIN connector to the mating 8 pin mini DIN connector marked as TUNER on the back of the radio 8 Push the POWER button on the tuner to the in position and then power on the radio Operation for FT 450 The operation of the MFJ 5124Y radio interface is similar to the operation of the F...

Page 36: ...eration 2 Turn the radio off Insert the 3 5 mm stereo phone plug into the tuner s RADIO INTERFACE jack 3 Insert the 2 1 x 5 5 mm coaxial power plug into the tuner s POWER jack 4 Insert the 8 pin modular plug into the MFJ 5124 s TO RADIO jack 5 Important Make sure the DC power to the radio has been turned off The radio does not fuse the DC power to the tuner and damage to the radio can occur if the...

Page 37: ...radio can occur if the interface s power connection comes in contact with ground 7 Connect the 8 pin mini DIN connector to the mating 8 pin mini DIN connector marked as TUNER on the back of the radio 8 Push the POWER button on the tuner to the in position and then power on the radio Operation for FT 950 The operation of the MFJ 5124Y radio interface is similar to the operation of the FC 40 describ...

Page 38: ... plug into the tuner s RADIO INTERFACE jack 4 Insert the 2 1 x 5 5 mm coaxial power plug into the tuner s POWER jack 5 Insert the 8 pin modular plug into the MFJ 5124 s TO RADIO jack 6 Important Make sure the DC power to the radio has been turned off 7 Connect the DB 9 connector to the mating DB 9 connector marked as CAT on the back of the radio 8 The FT 847 does not have a DC power connection on ...

Page 39: ...ess ENT to exit the Menu mode 2 Insert the 3 5 mm stereo phone plug into the MFJ 994B RADIO INTERFACE jack 3 Connect the 3 5 mm mono plug on the MFJ 5124Y3 to the REMOTE jack on the rear panel of the transceiver 4 Connect a 12V 1000 mA DC source to the MFJ 994B 5 Push the POWER button on the MFJ 994B to the in position The radio may be powered on either before or after the tuner is powered on Oper...

Page 40: ...he tuning process When tuning is completed the radio will stop transmitting and you will be ready for operation on this frequency Connections for FTDX 9000 series of radios 1 Before connecting the MFJ 5124Y3 to your radio set the maximum TUNE power of the radio as follows a On your transceiver enter the Menu mode by pressing the MNU key momentarily b Rotate the Main Tuning Dial knob until you see ...

Page 41: ...ial knob until you see menu item 145 tGEn TUN PWR on the transceiver s display c Rotate the SUB VFO B knob to select 20 watts for best SWR accuracy For the FT 2000D we recommend that this be set to 50 watts if the user normally operates at 100 watts output power when power is turned down to 100 watts the TUNE power will reduce to 25 watts If the operator normally has his FT 2000D set for the full ...

Page 42: ...by reading the manual you may call MFJ Technical Service at 662 323 0549 or the MFJ Factory at 662 323 5869 You will be best helped if you have your unit manual and all information on your station handy so you can answer any questions the technicians may ask You can also send questions by mail to MFJ Enterprises Inc 300 Industrial Park Road Starkville MS 39759 by facsimile FAX to 662 323 6551 or b...

Page 43: ...ises Inc 37 Figure 11 MFJ 994B Circuit Block Diagram Transmitter Antenna Remote Port Radio Interface Wire Impedance Sensor SWR Sensor Frequency Counter Memory Microcontroller Relay Drivers Ground Inductors 0 17 uH Capacitors 0 2950 pF SWR Wattmeter Push Buttons User Interface Z L Network ...

Page 44: ...MFJ 994B IntelliTuner Automatic Antenna Tuner Instruction Manual 2004 2010 MFJ Enterprises Inc 38 Note ...

Page 45: ...MFJ 994B IntelliTuner Automatic Antenna Tuner Instruction Manual 2004 2010 MFJ Enterprises Inc 39 Note ...

Page 46: ...MFJ 994B IntelliTuner Automatic Antenna Tuner Instruction Manual 2004 2010 MFJ Enterprises Inc 40 Note ...

Page 47: ...ervice Department at 662 323 0549 or the MFJ Factory at 662 323 5869 4 This warranty does not apply to kits sold by or manufactured by MFJ Enterprises Inc 5 Wired and tested PC board products are covered by this warranty provided only the wired and tested PC board product is returned Wired and tested PC boards installed in the owner s cabinet or connected to switches jacks or cables etc sent to MF...

Page 48: ...MFJ 994B Manual Version 2A Printed In U S A 02 2010 300 Industrial Park Road Starkville MS 39759 MFJ ENTERPRISES INC ...

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