Things You'll Need
Instructions
Turn on the wattmeter by pressing the on/off button. The screen will flash for 30 seconds the first time it is turned on.
Press the "light" button to turn on the screen's backlight if you are having trouble seeing the numbers.
Press the "auto" button to have the wattmeter automatically detect the power scale to be measured. If you already know the scale, you can override this by using the "up" and "down" buttons. To get an accurate reading, it is important to select the correct scale.
Press "FWD" or "RFL" to select whether forward or reflective power is to be measured.
Press "SWR" to measure the standing wave ratio. With the 4421 there is no need to calculate the standing wave ratio yourself.
Press "dBm" to see the forward or reflected power measured in decibels.