> -----Original Message----- > From: Ron D'Eau Claire [mailto:[EMAIL PROTECTED] > Sent: Sunday, July 16, 2006 9:00 PM > To: 'John A. Ross [Ecraft]'; [email protected] > Subject: RE: [Elecraft] What should the power output of the K2 be?
> Welcome to the K2-club John! I built mine in 2000. It's a FB rig. Ron Thanks, you are right, it is a very nice rig indeed and fantastic fun to build and work on. > The specified output of the K2 is at least 10 watts CW. The > actual output varies with the band. It is a function of the > overall transmitter path gain. > It tends to peak about 40 meters, where most K2's will make > 15 watts output, or very close to it. Up on 10 meters is > where the overall gain is lowest and many K2's just barely > make the specified 10 watts output. > Since you're still getting familiar with your K2, here's a > couple of things to remember: > > 1) The POWER control sets the "requested" power output. The > K2 monitors the actual power output and adjusts the > transmitter gain as needed for what you've requested. The > control allows you to "request" any power up to 15 watts, but > you can't get that much on all bands. OK, that makes sense now. I was not sure if the sample/control loop was doing something wrong. You never know when firmware has a part in it ;-) > 2) Because the POWER control circuitry is monitoring the > power output to determine how much gain the transmitter > circuits should have, the accuracy of the output power > setting depends upon how accurately the K2 measures its > output. A basic QRP K2 uses a simple RF voltmeter to monitor > the output. It is highly-dependent upon an accurate, > non-reactive 50-ohm load for good accuracy. Any significant > SWR at the transmitter output will affect it, and the actual > power output. The (KAT2, etc.) ATU's use a bridge circuit > that is a little more accurate, but can still be thrown off > by reactive terminations. I had not installed the ATU yet, Po was dumped into a DL-600 then checked again on a 2955B so I am pretty sure the loads were OK. > 3) If you change the POWER control setting you have to > transmit before the new power level takes effect, since the > K2 must sense the output RF to tell how to adjust the > circuits. That means that you may notice that the output is > nearly zero when you hit the first dit or dah after turning the K2 on. > It'll immediately jump up to whatever you have the control > set for. The same is in reverse when you turn the power down. > The first time you touch the key the power will still be up > at the old higher level until there's RF for the circuit to sense. OK, clear now. > 3) The K2 is rated at 10 watts PEP on SSB, regardless of how > much it will produce. That's because the distortion > increases above 10 watts PEP in SSB mode. CW doesn't need a > linear amp, so it's not an issue when you're pounding brass, > but don't exceed 10 watts PEP on SSB on any band. > > 4) The Bargraph power display is in peak power, so it'll show > flickers at the PEP peaks instead of the average power like > most inexpensive external meters. That cause confusion > sometimes when the opr notices that his external meter is > wiggling around at 3 or 4 watts while his K2 shows 10 watt > peaks on SSB. That's normal. The external meter is showing > the average output, not the peak. Cheers Ron All best John > > Ron AC7AC > > > > -----Original Message----- > > Hi all > > I have been having great fun with the K2 but I am wondering > what the output should be? > > 10W or 15W? > > The Po control seems to indicate 15W should be possible. > > The PA alignment seems OK, or at least as per the manual, > Po/current seems to match at the levels stated. > > But occasionally the built in detector seems to read a little > higher than the Po is set to and the full scale setting of 15 > only seems to yield 11w or so. > > As this is the only one I have built so far I am curious. > > Any guidance appreciated. > > John > > > _______________________________________________ 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
