MFJ MFJ-867, Manual

MFJ-868B Giant True Peak Reading SWR/Wattmeter 1.8-60 MHz 

Instruction M

3 

Power Measurement Scales

1.  The MFJ-868B Giant SWR/Wattmeter has three power scales.  Refer to Figure 2 

below for scale location and scale mark representation. 

2.  The meter’s full-scale forward and reflected power range is controlled by the 

20W / 200W / 2kW

 slide switch.  Select between 20, 200 or 2000 Watts. If your 

transmitter/amplifier runs less than 20 Watts of output power, push the slide 
switch all the way to the 

left

 for the 20-Watt scale.  If your transmitter/amplifier 

runs more than 20 Watts but less than 200 Watts of output power, push the slide 
switch to the 

middle

 position for the 200-Watt scale.

If your transmitter/amplifier 

runs more than 200 Watts of output power, push the slide switch all the way to the 

right

 for the 2000-Watt scale. 

3. On 

the 

2kW

 scale, each tall picket (scale mark) represents 100-Watts below the 

500 Watt picket and 500 Watts above the 500 Watt picket. The short pickets 
represent 50 Watts below the 500 Watt picket and 100 Watts above the 500 Watt 
picket 

4. On 

the 

200W

 scale, each tall picket represents 10-Watts below the 50 Watt picket 

and 50 Watts above the 50 Watt picket. The short pickets represent 5 Watts below 
the 50 Watt picket and 10 Watts above the 50 Watt picket 

5. On 

the 

20W

 scale, each picket represents 1-Watt. 

 
6.  The most accurate power readings occur in the upper half of the meter scales.  

When trying to measure power with a less than perfect match, the reflected power 
should be subtracted from the forward power reading in order to find the true 
power 
 

Figure 2: Power and Standing Wave Ratio Scales for MFJ-868B Giant SWR/Wattmeter