MFJ MFJ-1750, MFJ-1752 User Manual

MFJ-1750/1752
Instruction Manual

MFJ-1750/1752

Instruction Manual

Thank you for purchasing the MFJ-1750/1752. The 1750 is a 5/8
wave antenna designed for operation on 144-148 MHz. The 1752 is
designed to operate on the 220 MHz band.

The MFJ-1750/1752 is shipped partially assembled; you should have
received the following parts:
Item Quan. Desription

A 4 Radials
B 1 Chassis and radiator

assembly
C 1 Chassis cover
D 4 #6-32 x 1/2 screw &

nut
E 4 #6 self tapping screw
F 1 Clamp assembly

Assembly Instructions

1- Refer to Figures 1 and 2. Insert one of the 6-32 x 1/2 screws into
hole 1 and place a 6-32 nut on the screw. The screw should be
installed so that the nut is on the inside.

2- The four remaining screws and nuts can be installed in the same
manner, with one screw through hole 2, one through hole 3, and one
through hole 4.

3- You are now ready to install three of the radials. First posistion
the chassis as shown in Figures 1 and 2. Next insert a radial,
straight end first, into hole A. All radials must be inserted through
the hole from the inside of the chassis. The hooked end can now be
secured with the screw in hole 1.

4- Two more radials can be installed in the same way as the above
process. One radial should be inserted through hole B and secured
using the screw in hole 2. Another can be inserted through hole C and
secured by the screw in hole 3.

5- The remaining radial will emerge from the chassis through the
chassis through hole D located in the cover. To achieve this, loosely

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MFJ-1750/1752
Instruction Manual

fasten the screw in hole 4. The hook in the radial shoulb be turned
to match the others. The screw should be tight enough to hold the
radial, but should allow vertical movement, so that the cover might
be properly aligned.

6- Insert the radial through hole D, in the cover. Fasten the cover
to the chassis using the four #6 self tapping screws. Now the screw
in hole 4 should be tightened.

7- The clamp assembly should be assembled as shown in Figure 2.

SAFETY PRECAUTIONS

WARNING:

This antenna is an electrical conductor contact with power lines

-

can result in

death, or serious injuries.

- Do not install this antenna where there is any possibility of

contact

with power cables or service drop to buildings.

- The antenna supporting mast and/or tower should not be close to

any

power lines during installation or removal in the event the

system

should accidentally fall.

- Follow the guidelines for antenna installation recommended by

the

U.S. consumer product safety commission.

- Keep this antenna out of reach of adults, children, and animals.

Any contact

with this antenna while transmitting will cause severe RF

burns, and

voltages that KILL. The ends of the elements can cause eye

injuries, serious

RF burns or both.

- Keep the antenna away from you to prevent exposure to high

levels of

electromagnetic field radiation. Especially if you are using

more than 20

Watts of RF power.

- Never operate this antenna near RF sensitive medical devices

such as

pacemakers.

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MFJ-1750/1752
Instruction Manual

- Be careful while climbing and carrying the antenna. It is heavy

enough to

cause you to lose your balance if it is handled too casually.

Installation Instructions

The MFJ-1750/1752 can be mounted on any 1" to 1-1/2" tubular mast.
The mast may be a conductive (metal) or a non-conductive (pvc)
material.

WARNING:

For optimum performance the antenna should be mounted as high as
possible. However, if the mast itself is located on a high elevation,
such as a hill or mountain, the need for a tall mast will not be as
critical.

To mount the antenna on the mast, insert the mast into the clamp as
shown in figure 2. Make sure that the mast is mounted on the front of
the chassis, as shown in figure 2.

The coax from your radio may now be connected to the antenna. the
connector is an SO-239, so the connection should be fast and easy
using a standard PL-259 connector on you coax.

DO NOT MOUNT THIS ANTENNA NEAR POWER LINES!

Death or serious injury can result.

GROUNDING CONSIDERATIONS

Although this antenna is designed to operate efficiently without
equiring an earth ground, SAFETY GROUNDING must still be provided to
protect equipment, property, and people from the hazards of lighting
strikes and other weather related electrical discharges. The coaxial
cable feeding the antenna should have the shield grounded to
eliminate the risk of any indoor equipment failure and not allow
hazardous voltages to appear indoors and create a shock hazard.

Adequate protection can be accomplished by grounding the shield of
the coax where it enters the building to a good earth ground or
burying the cable in the earth for several feet before it enters the
building. For maximum lightning protection, during threatening
weather conditions, the coaxial cable should be totally disconnected
from the station.

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