MFJ-969 DELUXE Versa Tuner II
2
The 9 volt battery has one disadvantage, it limits meter accuracy at power levels over 250
watts. The 9 volt battery is disconnected when an external supply is used. An external
supply of 11 to 18 volts will permit use of the wattmeter above 250 watts.
The meter's full scale forward and reflected power range is controlled by the left-hand
METER switch. If your transmitter runs more than 30 watts of output power, set this
switch to 300W (in position). If your transmitter has less than 30 watts of output, set this
switch to the 30W switch position (out).
Forward power is displayed on the left-hand FORWARD meter scale. This scale is
calibrated from 0 to 300 watts and is read directly in the 300 watt position. Each picket
(scale mark) represents 25 watts between 300 and 100 watts, 10 watts between 100 and 10
watts, and has a single 5 watt picket below 10.
In the 30W position the forward power scale must be divided by 10. Each picket
represents 1/2 watt below 1 watt, 1 watt from 1 to 10 watts, and 2.5 watts from 10 to 30
watts.
Reflected power is read on the right-hand REFLECTED meter scale. This scale indicates
60 watts full scale when the 300W forward power sensitivity is selected, and 6 watts full
scale when the 30W power sensitivity is selected. This scale has a picket every 5 watts
above 10 watts and at each watt below 10 watts.
The reflected scale is also divided by 10 when using the 30W switch position.
When trying to measure power with a less than perfect match, the reflected power should
be
subtracted
from the forward power readings. The SWR is read directly from eleven red
SWR curves that range from 1:1 to infinity. SWR is measured by observing the point
where the forward and reflected power needles cross. The SWR is indicated by the red
curve closest to the needle crossing point. No cumbersome or time consuming SWR
sensitivity adjustments are required with this meter.
The wattmeter has an internal lamp that backlights the meter scale. The meter ON / OFF
switch turns the meter lamp off and on and disables or enables the meter circuit. 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.
The rear panel jack accepts a 2.1 mm coaxial plug with a positive center pin polarity.
Antenna Selector
The ANTENNA SELECTOR switch has eight positions. From counter-clockwise to
clockwise the positions are: DUMMY LOAD, BALANCED or SINGLE WIRE LINE,
COAX 1, and COAX 2 with the tuner matching circuits in line, and the reverse sequence
from COAX 2 back to DUMMY LOAD with the antenna tuning circuits bypassed.
