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MFJ-969 DELUXE Versa Tuner II
General Information
The MFJ-969 is a 300 watt RF output power antenna tuner that will match any transmitter
or transceiver to virtually any antenna. Peak or average forward and reflected power and
SWR can be read on the illuminated cross-needle meter.
The MFJ-969 uses a "T" matching network and covers all bands between 160 and 6 meters.
This network will tune dipoles, inverted-vees, verticals, mobile whips, beams, random
wires, and many other antennas. The MFJ-969 has rear panel connectors for coaxial, single
wire or two wire feedlines. A built-in 4:1 balun allows the use of balanced open wire,
twinlead, or twin-axial feedlines.
An internal eight position antenna-selector switch selects a built-in 50 ohm dummy load,
two separate coaxial line outputs, or a single wire line-balanced line output. All of these
functions can be selected in tuned (with tuner's "T" network in line) or bypassed (no tuning
circuit) configurations.
Peak Reading SWR/Wattmeter
The illuminated cross-needle meter measures the peak or average FORWARD power,
REFLECTED power, and SWR. The wattmeter is active in all ANTENNA SELECTOR
positions. To use the wattmeter without using the MFJ-969 tuning circuits select one of
the ANTENNA SELECTOR positions under BYPASS.
NOTE: The meter ON/OFF switch must be ON for the meter circuit to function. The
MFJ-969 wattmeter circuit does not function accurately if the Auto Tuner in
your radio is used. To disable the meter, turn the meter ON/OFF switch to the
OFF position. Set the ANTENNA SELECTOR switch to one of the bypass
positions when using the Auto Tuner in your radio.
Peak envelope power (PEP) is measured when the PEAK or AVERAGE METER push
button (right-hand side) in placed in the PEAK (in) position. Peak power and average
power values are equal with steady unmodulated carriers, FSK, or FM. The PEP power is
twice the average power with SSB two tone test modulation. PEP power may be any
amount larger than the average power with SSB voice signals.
The metering circuit in this unit provides very accurate forward peak power readings
during with any form of modulation.
operation, or an external supply can be used to power the peak detector. Current demand is
very low, and the 9 volt battery will last its' shelf life.
1
MFJ-969 Versa Tuner II
Instruction Manual
Either an internal 9 volt battery for portable
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Table of Contents
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Summary of Contents for MFJ MFJ-969 DELUXE Versa Tuner II
- Page 1 Instruction Manual General Information The MFJ-969 is a 300 watt RF output power antenna tuner that will match any transmitter or transceiver to virtually any antenna. Peak or average forward and reflected power and SWR can be read on the illuminated cross-needle meter.
- Page 2 The lamp circuit requires power from an external 12 Vdc source, such as the optional MFJ-1312B power supply. The external supply will also supply power for the peak power detector.
- Page 3 RF voltages may also damage anything contacting or within a half inch of the terminals. 3. Install the MFJ-969 between the transmitter and antenna. Use a 50 ohm coaxial cable to connect the transmitter or transceiver to the SO-239 (UHF female) labeled TRANSMITTER on the back of the tuner.
- Page 4 The chart in the tuning instructions shows typical capacitor settings that can be used for each amateur band. The ROLLER INDUCTOR in the MFJ-969 has maximum inductance in the full counter- clockwise position (at the highest number, around 117), and minimum inductance in the full clockwise rotation (at the lowest number, 000).
- Page 5 MFJ-969 DELUXE Versa Tuner II Adjustment Procedure When using the MFJ-969 in receive only applications, adjust the MFJ-969 for the highest "S" meter or signal level. The Tuning Chart can be used as a starting reference. To use the MFJ-969 for transmitting, follow the steps below: 1.
- Page 6 MFJ-969 DELUXE Versa Tuner II TRANSMITTER control, but power handling and efficiency are reduced. (It is normal for the TRANSMITTER setting to advance as operating frequency is increased.) 6. Increase the transmitter power until the Forward power level is full scale (30 watts) and observe the reflected power or SWR.
- Page 7 Antenna Hints WARNING: For operator safety a good outside earth ground or water pipe ground should ALWAYS be installed and connected to the case of the MFJ-969. Make certain the safety ground also connects to the transmitter and other station accessories. A wing nut post marked GROUND is provided for ground connection(s).
- Page 8 MFJ-969 DELUXE Versa Tuner II This problem often occurs on 80 meters if an odd quarter-wave (60 to 70 foot) open wire line is used to feed a half-wave (100 to 140 foot) dipole. The odd quarter-wave line transforms the dipole's low impedance to over three thousand ohms at the tuner. This is because the mismatched feedline is an odd multiple of 1/4 wavelength long.
- Page 9 MFJ Technical Service at 662-323-0549 or the MFJ Factory at 662- 323-5869. You will be best helped if you have your unit, manual and all information on your station handy so you can answer any questions the technicians may ask.
- Page 10 MFJ-969 DELUXE Versa Tuner II Schematic...
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