MFJ-989D VersaTuner V
Instruction Manual
8
[ ] Select a forward
Power
range (
LO for 300-W or HI for 3-kW
).
[ ] Select
PK
for peak-power readings or
AVG
for average-power readings.
[ ] View the
Forward
scale to read incident power.
[ ] View the
Reflected
scale to read reverse power.
[ ] For SWR, find the red curve closest to where the two meter pointers intersect. The red SWR curves
provide a reliable estimate of SWR without the inconvenience of adjusting a sensitivity control to
calibrate the meter. Each red line on the meter is marked with a SWR value.
1.) Power Readings:
For continuous carrier (CW or FM) modes,
Peak
and
Average
power readings
should measure virtually the same. For SSB voice,
Peak
readings may measure 3 to 5 times higher than
the
Average
power, depending on speech characteristics and the amount of speech processing being
used. Two-tone-test
Peak
readings should measure twice the
Average
power readings. Readings taken
along the upper two-thirds of the meter scale are typically more accurate than those made along the
lower third.
2.) Measuring Power with SWR:
When measuring transmitter power into a mismatched load
indicating reflected power, remember to subtract the
Reflected Power
reading from the
Forward Power
reading:
(Po = FP - RP)
.
3.) Precision SWR Readings:
To obtain
precise
SWR data using the split meters, write down the
Forward
and
Reflected
power measurements (in Watts) and plug them into the formula shown below:
SWR =
1 +
Pr
Pf
1 -
Pr
Pf
Pr = Reflected Power
Pf = Forward Power
Antenna Selector
The
Antenna Selector
is a heavy-duty six-position RF switch that routes the tuner's
Transmitter
input
line as described below:
Coax-1 Direct:
Transmit line passes directly to
Coax-1
output.
Coax-2 Direct:
Transmit line passes directly to
Coax-2
output.
Dummy Load:
Transmit line passes directly to the internal
50-Ohm load.
Coax-1:
Transmit line goes through the T-network to
Coax-1
output.
Coax-2:
Transmit line goes through the T-network to
Coax-2
output.
Wire/Bal. Line:
Transmit line goes through the T-network to the
Wire
terminal post.
