Fred, Yes, the KPA100 (and the KAT2 and the KAT100) contain a directional coupler type wattmeter to indicate the forward power and the SWR. These wattmeters remove the necessity for operating the K2 into a 50 ohm non-reactive load in order to obtain power accuracy. The forward power output of these wattmeters is used to control the K2 power output as well as display it on the LED (and on the LCD during TUNE).
These internal wattmeters need to be calibrated with some external reference power metering if they are expected to be accurate. I measure the RF Voltage across a 1% precision 50 ohm non-reactive dummy load for the calibration, and I feel I can calibrate the wattmeter to within 5% using that method. Many wattmeters available to hams are simply not that accurate. Even the Bird specs its accuracy at 5% of full scale ONLY after proper calibration - and with a 100 watt slug, that means the power reading can be up to 5 watts off at any power level. Know your instruments and know just how much to trust what they tell you. 73, Don W3FPR > -----Original Message----- > > I saw a reference to a "wattmeter in the KPA100"? > > Does the K2's "KPA100" option, include a wattmeter, > beyond what metering is now present in my K2's > relative reading LED multi-segment indicator? > > What comes with the KPA100, in this area? If I > bought the KPA100 option, for my K2 - could I get > a accurate indication if I'm putting out 10watts, > 38 watts or 100 watts? Or if the SWR presented to > the KPA100 is 1:1 or 11.6:1? > > I'm really trying to decide whether to bite on > the KPA100 higher-power K2 option. > > Thanks, > Fred N3CSY _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
