MFJ-1784
Giant Box Fan Portable Loop Antenna
Instruction & Technical Manual
above ground.
Since ground-wave signals only propagate well along the earth when they are vertically polarized, a
horizontally-polarized loop may not respond to some local noise sources. Like all other antennas, a
small loop is generally a quieter receiving antenna when horizontally polarized. This also means
that a horizontally polarized loop is not a good choice for local ground wave communications. It is
an excellent choice for medium to long distance sky wave communications, however.
2.3
FEATURES
•
Air-variable Butterfly Capacitor:
The 213 pF capacitor can handle 15 kV
•
Welded Aluminum Construction:
Aluminum segments are welded to maximize
conductivity
•
Single-cable Control:
RF and DC sent along a single piece of coax
•
Foldable Fiberglass Feet:
Feet are designed to rotate out of the way for mounting
•
Convenient Carry Handle:
An ergonomic aluminum handle makes carrying the
MFJ-1784 a breeze
3
SYSTEM SETUP & OPERATION
Figure 5 shows a simple layout for a portable station using the MFJ-1784. Connect the controller,
either the standard one or the Deluxe Loop Controller, between the radio and the MFJ-1784. Key
the radio at low power (
<
10W) and adjust the antenna to match using the either radio’s SWR
meter or a simple one such as the MFJ-818.
WARNING
Do not install any devices between the controller box and the loop antenna. If anything causes a
low DC resistance or short between the center conductor of the coax and ground, the control box or
power supply will be damaged.
Figure 5: Typical Station Setup
∗
Do not expect the best results if you mount this loop antenna horizontally less than 15 feet above ground.
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Summary of Contents for MFJ-1784
Page 13: ...USER NOTES ...
