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MFJ-1775 Rotatable Mini-Dipole 

                                                 Instruction Manual 

 

 

2

MFJ-1775 6-Band Rotatable Mini-Dipole 

 

Introduction 

 

The MFJ-1775 is a mini 14-foot rotatable dipole that is almost invisible from across the street. With its 
tiny 7-foot turning radius, it fits on the smallest roof and is perfect for town houses, apartments and 
condos.  If necessary, it can even be mounted inside an attic! 

The MFJ-1775 is inconspicuous and low profile -- not much bigger than a TV antenna, and can easily be 
turned by a lightweight TV rotator such as the Hy-Gain AR-35. 

And this antenna is no wimp! Its bi-directional pattern can help reduce QRM/noise while maximizing 
your signal in the directions that you want -- so you can work some real DX. You can operate 6 bands -- 
40, 20, 15, 10, 6 and 2 meters -- and run up to a full 1500 Watts SSB on all HF bands. 

The MFJ-1775 features automatic band switching, and uses highly efficient end-loading with its entire 
length always radiating. With 6 and 2 Meters thrown-in, you have ham radio’s most versatile rotatable 
dipole! 

Each HF band uses separate, efficient end-loading coils wound on fiberglass forms with Teflon

TM

 wire, 

and capacitance hats (no lossy traps). 6 and 2 meters are full-length half-wave dipoles. 

The MFJ-1775 is built-to-last – using an incredibly strong, solid fiberglass rod center insulator and 6063 
T-6 aircraft strength aluminum tubing for the radiator. And it assembles in an afternoon.  

 

WARNING: Improper installation and assembly can be hazardous!  Read these instructions 
thoroughly before attempting to assemble, install or operate this product!  High power transmitting 
devices produce voltages that can cause severe burns or other injuries. 

 

SPECIFICATIONS 

 

The small size of the MFJ-1775 is accomplished by adding separate loading coils and capacitance hats at 
each end of the antenna for the HF bands.  The efficient end-loading coils are wound on fiberglass forms.  
The six and two meter amateur bands are covered with the addition of four quarter-wave decoupling 
stubs.   

 
Electrical Specifications 
 
 

 

 

Power   

 

Band  

CW SSB 

2:1 SWR BW 

40m 

 

1500  1500     40 KHZ 

20m 

 

1500  1500     60 KHZ 

15m   

1500 1500  

400 

KHZ 

10m 

 

1500  1500    1.2 MHZ 

6m   

300 750  

600 

KHZ 

2m 

 

200 

300 

  4.0 MHZ 

 
Mechanical Specifications 

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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