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MFJ-1775 Rotatable Mini-Dipole 

                                                 Instruction Manual 

 

 

6

7) Slide the 1-1/8 x 60” aluminum radiator tubes over the center insulator/balun assembly with the 

slot on each aluminum tube on the topside of the fiberglass rod/balun assembly.  Insert the ¼-20 
bolts through the aluminum tube/fiberglass assembly and through the balun lugs.  Add the ¼-20 
split lock-washers and nuts and tighten securely.  See Figure 3. 

 
 

 
 
 
 
 
 
 
 
 
 
 
 
 

8) Slide four hose clamps over each aluminum tube. Slide two hose clamps (one on each aluminum 

radiator tube) up against the ¼-20 hardware and clamp the four aluminum stub channel brackets 
(two on each radiator) on opposite sides of the aluminum radiator tubes as shown in 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 stubs by threading a 10-32 x 3/8" nut 1/2" near the end of the threads.  Add a 

second nut and lock-washer to sandwich the bracket between the two nuts, leaving no more than 
¼” of threaded rod exposed beyond the aluminum bracket. See Figure 4.   

 

IMPORTANT:  Use a 5/16” nut driver to tighten the capacitance spokes in place.  Tighten 

by hand only.  A high torque electric screwdriver will shear the screws.

  

Figure 3:  Radiator Tube Assembly – Top View

Fiberglass Rod 

Balun wire 
(2 plcs) 

Slot 

¼-20 hdwr 
(2 plcs) 

AL Radiator (2 pcs) 

Balun 

¼-20 hdwr
(end view) 

~3”

~20” 

Balun 

Figure 4:  6 and 2-meter stub assembly and mounting 

~35” 

~11” 

AL brkt 

Fiberglass brkt 

Fiberglass brkt 

AL brkt 

#10 nuts (2), 
LW (1) – 4 plcs 

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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