Elecraft KPA500 Owner's Manual - Manual (Page 22)

22
Wattmeter Calibration Procedure
If you have a wattmeter that you feel is more accurate than the KPA500 wattmeter, you can adjust the KPA500
wattmeter to match its readings as follows. The calibration is done per-band so you can make adjustments for
individual bands without affecting the others.
In addition to your wattmeter, you will need a good dummy load capable of handling 500 watts.
 Connect your wattmeter to the KPA500 RF Output using short, direct 50 ohm coaxial cable.
 Connect your dummy load to the wattmeter.
 Select the band that you wish to calibrate.
 Tap
P W R on the KPA500 to display the RF power output on the LCD.
 Transmit briefly at 500 watts output into the external wattmeter and dummy load and compare the
reading on the external wattmeter with the KPA500 wattmeter.
 If you wish the adjust the power displayed on the KPA500 LCD and LEDs, hold
M E N U and tap
switches next to the and symbols until PWR ADJ is displayed on the LCD.
 Hold
E D I T . A number between 80 and 120 will be displayed on the LCD.
 If the power displayed on the KPA500 wattmeter needs to be higher, tap the switch. If the power
displayed on the KPA500 needs to be lower, tap the switch. The number displayed indicates the
percentage change in the power reading. For example, changing 100 to 110 will result in a 10% increase
in the power indicated.
 Tap
M E N U twice to exit the menu. The current band will be displayed on the LCD.
 Tap
P W R on the KPA500 to display the RF power output on the LCD.
 Transmit again and compare the readings on the KPA500 and your external wattmeter. Repeat the
procedure as needed until you are satisfied with the readings.