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MFJ-1756 Instruction Manual 

6 Meter Ground Plane Antenna 

MFJ-1756  6 METER GROUND PLANE ANTENNA 

 

INTRODUCTION 

 

The MFJ-1756 Ground Plane Antenna features a DC grounded element and a ground 
isolated radial system for improved performance. 
  
The ground isolated radial system, unique to the MFJ-1756 antenna, reduces undesirable 
feedline and supporting structure radiation by eliminating common mode current paths.  
This unique system improves transmission by producing a much cleaner pattern with 
more signal at desired angles, and also reduces conducted noise reaching the antenna over 
the outside of the feedline or antenna support.  It also insures that the length of the 
feedline or support does not change the antenna's resonant frequency or SWR. 
 
The MFJ-1756 is easily cut for the desired area of the six meter band.   A rugged low 
impedance air insulated matching stub provides convenient adjustment of base impedance 
(a normal ground plane is much less than 50 ohms) allowing adjustment to a perfect 1:1 
SWR.  Power capability is 1000 watts RF continuous.  

 

CHOOSING A LOCATION FOR THE ANTENNA 

 

WARNING: 

Improper installation and assembly can be 
hazardous! Read these instructions thoroughly 
before attempting to assemble, install or operate 
this product!   Always mount this antenna so that 
it is out of the reach of adults as well as 
children. High power transmitting devices produce 
voltages that can cause severe burns or other 
injuries. 

 

For the best performance on receiving and transmitting, mount this antenna in a clear 
location at least a few feet above or 20 feet away from buildings, towers, feedlines, utility 
wires, and other antennas. While your own ingenuity and particular circumstances will 
determine the final mounting method, we will pass along some rules that can not be 
neglected. 
 

Never

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

contact with the radials 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 feed line at the point where it enters a building to a good earth ground 

for lightning protection. 
 

Summary of Contents for MFJ-1756

Page 1: ...to a perfect 1 1 SWR Power capability is 1000 watts RF continuous CHOOSING A LOCATION FOR THE ANTENNA WARNING Improper installation and assembly can be hazardous Read these instructions thoroughly be...

Page 2: ...find the following items Before attempting to install this antenna check the parts bag to insure that all hardware is accounted for In the event anything is missing please contact MFJ Enterprises Inc...

Page 3: ...ds through the ceramic insulating post on top of the antenna base Thread the 10 32 nut on the 10 32 screw and tighten with a 3 8 open end wrench Do not over tighten B Locate the hole on the top of the...

Page 4: ...directions Refer to Figure 4 for an illustration of the radial assembly Step 3 Insert a radial through the two left holes located on the front and rear of the base Refer to Figure 3 and the holes lab...

Page 5: ...the radials in place stack the two stainless steel plates together and place them over the radials in the bottom of the antenna base See Figure 5 Place one lock washer on each of the 10 32 Phillips h...

Page 6: ...e U bolt See Figure 6 Figure 6 U bolt assembly B Place the U bolt around the mast not included and install the saddle on the U bolt Be sure the saddle is in the correct position to bite into the mast...

Page 7: ...he other fiberglass plate through the U bolt from the front of the antenna base Place the lock washers over the U bolt and hand thread the nuts on the bolt Tighten the nuts securely with the 7 16 open...

Page 8: ...Cutting measurements for tuning between 50 and 54 Mhz FREQUENCY RADIATOR LENGTH CUT LENGTH 50 Mhz 54 3 4 INCHES 0 INCHES 51 Mhz 52 7 8 INCHES 1 7 8 INCHES 52 Mhz 51 INCHES 3 3 4 INCHES 53 Mhz 49 1 8 I...

Page 9: ...the coax 3 to 4 from the mast for 50 Use an insulator PVC pipe if necessary Below the 50 air spaced length tape the coax to the mast and keep the coax taped against the mast for at least three feet TE...

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