Controller Box Installation; Controller Box Operation - MFJ Box Fan -1780 Instruction Manual

MFJ-1780 Box Fan    Loop Antenna
In order to be on the safe side and minimize exposure to RF radiation, for example; place the
antenna in a different room than the one you are operating from. To keep it out of reach of
children or other adults it is advisable to have the antenna located in a locked room.

CONTROLLER BOX INSTALLATION

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.
The controller box of the MFJ Box Fan Loop can be installed at any position that allows easy access to
the controls of the unit and the transceiver. The coax lines should be good quality 50 ohm lines and be
kept reasonably short to reduce losses. If you use quality low-loss cable the exact lengths used are not
important and will not effect the operation or SWR of the system.
If you are using a lossy cable between your antenna and controller and have problem tuning, the easiest
way to correct the problem is to get better quality cable.
You must only use the MFJ-1312B supply or batteries to operate this unit. If you chose to use an other
power supply to power this unit, the power supply must not have a common ground with anything else
in your radio system.
CAUTION!: THE POWER SUPPLY OF THIS UNIT MUST NOT BE GROUNDED! IF
EITHER THE POSITIVE OR NEGATIVE LEADS ARE GROUNDED THE CONTROL UNIT
WILL BE DAMAGED! USE ONLY THE MFJ-1312B power SUPPLY WITH THIS UNIT!

CONTROLLER BOX OPERATION

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.
NOTE
In order to operate this antenna and be able to tune it, a wattmeter (capable of reading forward
and reflected power), or an SWR meter is
the transmitter and the controller box of the system. (see figure 7)
The controller box supplies control voltages to the loop antenna through the coaxial feedline. These
voltages are low voltage and low current so that the length of the coaxial line does not affect the
operation of the motor. It is important that the feedline remain water-free and that there are no short
circuits between the center conductor and the shield of the feedline.
Figure 5
required.
This extra meter should be placed in between
7
Instruction Manual