Many people object to the use of high power with PSK modes because many people operate within a small section of the band and a strong signal can make life difficult for other users. But the difference between 40W and 100W is only about 4dB, less than an S point, less than the difference between a good antenna and a so-so one and less than the typical variation in signal strength caused by QSB. If you are close (geographically) to someone else using PSK31 they are going to be strong whatever the power they are running.
The most important thing when using PSK modes is not how much power you are using, but that the signal is *clean*, with the minimum of IMD products. And that is why with a barefoot K3 or any other 100W radio you should not exceed about 40W output. The K3 will certainly handle running 100W output without overheating. But you will not be a good neighbour to other users because the IMD will deteriorate substantiually as the power increases. If you had a KPA100 then I dare say you could run 100W output and be a better neighbour than someone running 40W with a barefoot rig. The reason it is necessary to run higher power when using RTTY is that it is an antiquated mode designed before the advent of DSP and it requires a stronger signal to produce good copy than PSK31. The reason it is OK to run 100W of RTTY using a barefoot K3 is because RTTY is a constant amplitude FSK mode and does not cause any IMD. Don Wilhelm-4 wrote: > > Giorgio, > > The safe power for the K3 is 100 watts. A operator using more than 20 > to 50 watts for PSK31 is IMHO a "band hog" - PSK31 operation at QRP > levels is quite common and should not be abused by those running high > power (even though many do it). > > OTOH, RTTY is different because many operators are running the full > legal limit, but I have worked several RTTY stations in a contest using > only 100 watts. > > ----- Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Observations-Digital-Modes-and-SSB-tp5976035p5984101.html Sent from the [K3] mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
