MFJ 1789, Instruction Manual

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MFJ-1789 Rotatable Mini-Dipole Instruction Manual
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MFJ-1789 9-Band Rotatable Mini-Dipole
Introduction
The MFJ-1789 is a mini 18-foot rotatable dipole that is almost invisible from across the street. With its
tiny 9-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-1789 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 9 bands --
40,30, 20,17, 15,12,10, 6 and 2 meters -- and run up to a full 1500 Watts SSB on all HF bands.
The MFJ-1789 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-1789 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-1789 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
30M 1500 1500 50 KHZ
20m 1500 1500 60 KHZ
17m 1500 1500 200KHZ
15m 1500 1500 400 KHZ
12M 1500 1500 800 KHZ
10m 1500 1500 1.2 MHZ