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MFJ-1625 Instruction Manual
MFJ-1625 Window/Balcony Mount Antenna
Introduction
The MFJ-1625 Window/Balcony Mount Antenna was designed to provide portable or permanent HF
communications on 80 through 10 meters and VHF on 6 meters. The universal mount design allows the
user to install the antenna in many ways. The mount will easily attach to window frames, balconies, and
railings. The MFJ-1625 works well indoors mounted to a desk or table as well.
The antenna consists of a whip tuner designed for tuning short whips as well as virtually any random
length wire antenna, collapsible whip, universal mount, and counterpoise wire. The operating frequency
is found by turning the knobs on the whip tuner and setting them for maximum RF current. The
counterpoise wire length can also be adjusted for maximum RF current. The MFJ-1625
Window/Balcony Mount Antenna will allow the operator to get on the air from locations where antenna
size is limited.
The whip tuner section uses a reversible "L" network. The advantage of the "L" network is that it has
only two tuning controls, and only one tuning solution for given impedance match. The MFJ-1625 has
rear panel connectors for coaxial input and a "Hi-Z/Lo-Z" switch for reversing the "L" network. An
internal input-isolating current balun provides isolation of DC and RF grounds for optimum tuning of the
RF counterpoise.
An RF Current Meter indicates the summed antenna and counterpoise antenna currents, making tuning
particularly easy. Simply tune for maximum RF current.
MFJ-1625 Supplied Components (80-10 meter operation)
• MFJ-1956 12 ft. telescopic whip antenna
• Counterpoise assembly (6, 14, and 26 ft. long wires)
• MFJ-63 Loading Coil Assembly for 40-80 meter operation with the MFJ-1956 12 ft.
telescopic whip antenna
Choosing a Mounting Position
WARNING: ALWAYS ATTACH THE SAFETY ROPE TO A STABLE SUPPORT
BEFORE ATTEMPTING TO ATTACH THE UNIVERSAL MOUNT TO A
WINDOW FRAME OR RAIL. INJURY AND DAMAGE COULD OCCUR
IF THE ANTENNA WERE TO FALL.
1. Locate the MFJ-1625 in a convenient location. The best performance will be obtained by
placing the antenna outside, however the antenna may be used indoors if necessary. Avoid
placing the tuner near microphones, speech processors, computers, TNC's or other RF
sensitive devices.
Window/Balcony Mount Antenna
1
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Related Manuals for MFJ MFJ-1625
Summary of Contents for MFJ MFJ-1625
- Page 1 The whip tuner section uses a reversible "L" network. The advantage of the “L” network is that it has only two tuning controls, and only one tuning solution for given impedance match. The MFJ-1625 has rear panel connectors for coaxial input and a “Hi-Z/Lo-Z” switch for reversing the “L” network. An internal input-isolating current balun provides isolation of DC and RF grounds for optimum tuning of the RF counterpoise.
- Page 2 MFJ-1625 Instruction Manual Window/Balcony Mount Antenna 2. The design of the antenna allows it to be installed in many ways. It can be easily attached to a window frame, window box or balcony railing. A Wooden fence is another common mounting location.
- Page 3 9. Decide which mount hole will be used on the mounting bracket according to your situation. There are five holes available. 10. Connect the MFJ-63 Loading Coil Assembly and the MFJ-1956 12 ft. telescopic whip antenna to the 3/8x24 stud on the top of the mounting bracket and extend to its full length.
- Page 4 RF SENSITIVITY control as necessary to keep from pinning the RF Current meter. Note: The MFJ-1625 will reduce the SWR of most antenna systems to below 1.5:1. Maximum RF current also corresponds to minimum SWR. This can be verified with an external SWR meter if desired.
- Page 5 MFJ-1625 Artificial Ground The MFJ-1625 contains a series L-circuit that is used to tune the RF ground system (either a counterpoise or a ground wire). Maximum ground current will flow through the MFJ-1625 RF current meter when the COUNTERPOISE switch is properly set.
- Page 6 If the station ground has a long lead, you can connect it to the COUNTERPOISE binding post of the MFJ-1625. Connect the station ground bus and accessories to the GROUND post. Do not reverse these wires. Follow the same procedure for maximizing RF Current described in the tuning procedure.
- Page 7 MFJ-1625 Instruction Manual Window/Balcony Mount Antenna Schematic...
- Page 8 MFJ-1625 Instruction Manual Window/Balcony Mount Antenna Tuning Chart You may wish to remove or make a copy of this page and place it near the tuner. Insert your own values for each frequency according to your station. Freq MHz Counterpoise...
- Page 9 MFJ-1625 Instruction Manual Window/Balcony Mount Antenna...