MFJ MFJ-989D - Operating the SWR;Wattmeter; Measuring Power and SWR; Antenna Selector Operation

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.