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MFJ-1740 

INSTRUCTION MANUAL 

Thank you for purchasing the MFJ-1740 1/4 wave antenna. The MFJ-

1740 is designed for use on 144 to 148 MHz. However, simple trimming 
of the radiator and radials will yield a 1/4 wave antenna for 220 MHz 
band, or a 1/4 wave antenna for 440 MHz band. 

 

The MFJ-1740 is shipped partially assembled; you should have re-

ceived the following: 

Item 

Quan. 

Description 

Radials 

Chassis 

6-32x1/2 

screw, lockwasher & nut 

D  

I  

Clamp assembly 

 

ASSEMBLY 

INSTRUCTIONS 

Step 1: 

f

-

 

Refer to figure-1. Insert the lockwashers over the 6-32 

screws. Insert one of the three 

6-32 x 

1/2 screws through hole 1 

and 

start a 

6-32 

nut on the screw. The screw should be installed so that 

the nut is on the inside. The three remaining screws and nuts 
should be installed in the chassis in a like manner, with one screw 
through hole 2, and the other screw through hole 

3. 

Step 2: 

Now you are ready to install the three radials. First 

position the chassis as shown in figure-2. Then insert a radial, 
straight end first, into hole A. All radials must be inserted 
through from the inside of the chassis. The hooked end of the 
radial can then be fastened using the screw in hole 1. 

 

NOTE: When installed, the radials should emerge  from 

the chassis at a downward angle away  from the 
radiator. NO BENDING IS NECESSARY. 

 

The two remaining radials can be installed similarly. 

One radial should be inserted through hole B and secured with 
the screw in hole 2, and the other radial should be inserted 
through hole C and secured with the screw in hole 

3. 

STEP 

3: 

Assemble the clamp in the chassis as shown in figure-2. 

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