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MFJ-1775 Rotatable Mini-Dipole 

                                                 Instruction Manual 

 

 

3

 
Mast Size: 

 

1- to 1-1/2” diameter 

Overall Length: 

14 feet 

Turning Radius: 

7 feet 

Weight:   15 

pounds 

Wind Load: 

 

2 square feet 

 

CHOOSING A LOCATION FOR THE ANTENNA 

 

For best performance on receiving and transmitting, mount the antenna in a clear location above or away 
from buildings, towers, feedlines, utility wires, and other antennas.  While your own ingenuity and 
particular circumstances will determine the final mounting method, we'll pass along a few ideas for both 
permanent installation and portable operation. 

 

• 

Never

 mount this antenna in a location that will permit unsuspecting people to come in contact with 

the loading spokes or any other part of the antenna. 

• 

Never

 mount this antenna where a mechanical failure might allow the antenna to contact power lines 

or other utility wires. 

• 

Always

 ground the feedline at the point where it enters a building to a good earth ground for 

lightning protection.

 

 
WARNING: Always mount this antenna so that it is out of the reach of adults and children.  
The capacitance elements can cause injury and/or severe RF burns. 

 

Permanent Installation 

The ideal installation is a rigid pole or roof mount that puts the antenna completely in the clear.  If the 
ideal installation is not possible, choose the best compromise.  TV mast, heavy-duty rigid electrical 
conduit, and steel water pipes are suitable mast materials.  This antenna will mount on masts between 1 
and 1-1/2" OD.  The use of soft or thin wall masts is not recommended 

 

Portable Operation 

The MFJ-1775 may be disassembled as necessary for transporting to a temporary location.  Ideally, just 
remove the two HF loading coil assemblies leaving the two main elements and 2- & 6-meter stub 
assemblies intact. 

Some retuning may be required after moving the antenna.

 

 
Even for temporary or portable operation, do not be casual about selecting a suitable mast.  If the antenna 
falls, it will be damaged and may cause serious injury.  Whatever type of installation you choose, 
remember that the antenna should be installed where it can 

never

 be contacted by people or animals or 

come in contact with power lines. 

 
 

 
 
 

 
 

Summary of Contents for MFJ-1775

Page 1: ...6 6 Aluminum Stub Channel Bracket 4 808 1796 5 1 x 12 Fiberglass Rod 1 808 1775 12 1 1 8 x 60 AL Tube 2 810 1796 2 30 LONG Spokes 4 810 1796 3C 26 MEDIUM Spokes 8 810 1796 5C 12 SHORT Spokes 24 810 17...

Page 2: ...rsatile rotatable dipole Each HF band uses separate efficient end loading coils wound on fiberglass forms with TeflonTM wire and capacitance hats no lossy traps 6 and 2 meters are full length half wav...

Page 3: ...s mount this antenna so that it is out of the reach of adults and children The capacitance elements can cause injury and or severe RF burns Permanent Installation The ideal installation is a rigid pol...

Page 4: ...e you to lose your balance if it is handled too casually or if the capacitance spokes are snagged on a gutter ladder tree limbs etc 2 Mount the antenna high enough so that it is out of reach The ends...

Page 5: ...bolts Heavy wire cutters for trimming capacitance spokes Pliers for holding the spoke ends as they are trimmed Safety glasses 5 Assemble the four small L brackets to the four long fiberglass insulato...

Page 6: ...n Figure 4 9 Using eight hose clamps four on each radiator clamp the fiberglass insulators so as to support the 16 and 55 threaded rods Position the insulators as shown in Figure 4 10 Mount the four s...

Page 7: ...ng 12 Install four short spokes in the 20 meter rings of both loading coil assemblies With a 5 16 nut driver tighten the nuts until the spokes are snug 13 Install four short spokes in the 15 meter rin...

Page 8: ...ed on a tall support will make adjustments difficult and time consuming It is best to install the antenna on a short temporary mast or pipe that is located in a reasonably clear location for tuning Th...

Page 9: ...as to keep the cut piece from flying off and causing injury The following tips will help you obtain a better SWR on 40 meters than the tuning method used on other bands On 40 meters the lowest SWR is...

Page 10: ...e stub fully extended and 148 MHz with the stub fully contracted NOTE The 2 meter resonance is affected by other resonances in the overall antenna structure You may find a fixed resonance close to the...

Page 11: ...owing hazardous voltages that could create a shock hazard Adequate protection can be accomplished by grounding the shield of the coax to a good earth ground where it enters the building or directly bu...

Page 12: ...SSISTANCE If you have any problem with this unit first check the appropriate section of this manual If the manual does not reference your problem or your problem is not solved by reading the manual yo...

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