MFJ-1890
2 Element Moxon Beam for 10 meters
INSTRUCTION MANUAL
CAUTION: Read All Instructions Before Operating Equipment
300 Industrial Park Road
Starkville, MS 39759 USA
Tel: 662-323-9715 Fax: 662-323-6551
COPYRIGHT 2 01 2 MFJ Enterprises Inc. R ev 1A
C
GENERAL DESCRIPTION
The Moxon Rectangle is a close-spaced 2-element Yagi consisting of a driven element
and a reflector with the element tips folded toward each other to reduce turning radius.
The Moxon features a broad cardioid pattern with roughly 3.3 dBd of foward gain and
front to back ratio measuring -30 dB or more. Spanning just over 12 feet and weighing
only a few pounds, it is well suited for rooftop installations using lightweight TV hardware.
Choosing a location
For best performance on receiving and transmitting, mount the antenna in a clear location
above or away from buildings, towers, feedlines, utility wires, and other antennas. While
your own ingenuity and particular circumstances will determine the final mounting method,
we’ll pass along a few ideas for both permanent installation and portable operation.
Never mount this antenna in a location that will permit unsuspecting people to come in
contact with the antenna elements.
Never mount this antenna where a mechanical failure might allow the antenna to contact
power lines or other utility wires.
Always ground the feedline at the point where it enters a building to a good earth ground
for lightning protection.
WARNING Always mount this antenna so that it is out of reach of adults and children.
The elements can cause injury and/or severe RF burns.
WARNING
WHEN INSTALLING YOUR SYSTEM, TAKE EXTREME
CARE TO AVOID ANY ACCIDENTAL CONTACT WITH
POWER LINES OR OVERHEAD OBSTRUCTIONS.
FAILURE TO EXERCISE THIS CARE COULD RESULT
IN SERIOUS OR FATAL INJURY
2
Permanent Installation
The ideal installation is a rigid pole or roof mount that puts the antenna completely
in the clear. If the ideal installation is not possible, choose the best compromise.
TV mast, heavy-duty rigid electrical conduit, and steel water pipes are suitable
mast materials. The use of soft or thin wall mast is not recommended.
Portable Operation
The MFJ-1890 may be easily transported to temporary locations for portable,
emergency, and contest operation. Even for temporary or portable operation, do not
be casual about selecting a suitable mast. If the antenna falls, it can be damaged and
may cause serious injury. Whatever type of installation you choose, remember that
the antenna should be installed where it cannot be contacted by people or animals or
come in contact with power lines.
Antenna Assembly
Assemble the antenna on a flat level surface. Avoid assembly over grass as you may
drop some of the parts and never find them again. You may use a couple of saw horses
or other means of support to aid assembly. Loosely assemble the #1 and #11 brackets
using the 1/4-20 nuts, bolts and washers as shown in figure 1. Don't forget the square
nuts that go inside the brackets. The square nuts are different for each bracket and also
take different bolts.
24
14
This hole should be 3 inches
from the end of the boom
19
24
22
25
16
Figure 1
3
Install the 5/8 elements into the bracket while it is loose on the boom. Tighten them
enough to hold the element but allow for the bracket to rotate on the boom as you
will have to align the elements with the mast when the antenna is fully assembled.
15
20
21
15
14
10
1
9
25
16
Figure 2
Secure the driven element insulator to the other end of the boom also allowing 3 inches
from the center of the bracket to the end of the boom. Install the remaining two main
elements to the insulator as shown in figure 2. Leave the bracket loose enough to align
the elements when the antenna is finished.
28-1/2”
6-1/4”
20-1/2”
Short end
#4 hose clamp
7/16 x .028 x 26
3/8 x 9 insulator
7/16 x .028 x 18
Short end
7/16 x .028 x 26
Assemble the end elements as shown in figure 3.
Use the #4 hose clamps to secure the tubing
together. The corner tubes have one side longer
than the other. The short end should insert into the
7/16 x 20 elements. Repeat this assembly again
to make the other side of the antenna.
7/16 x .028 x 26
Figure 3
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