LS, With respect to power in PSK, I'd be just as concerned about signal quality (IMD, splatter) as about the power handling capability of the finals. PSK is extremely sensitive to IMD.
Instantaneous peak power in PSK can be twice the average power. Even if the amplifier is within its thermal ratings at full power, if instantaneous peaks are clipped your transmitted signal will have increased IMD. Operating below half the rated power should be OK, but you might want to do some on-air IMD testing before routinely using powers above half the rated power in PSK. RTTY is a different story. The main issue in RTTY is not IMD, it is keying transients. These are visible as peaks in the frequency spectrum separated by multiples of the 45 baud keying rate. In the limited testing I have been able to do, I have not noticed any sensitivity of RTTY keying transients to output power. What I have seen, however, is that my K3's AFSK signal is cleaner than the FSK signal - it's not that the FSK signal is bad, just that the AFSK keying transient peaks are lower. I believe Chen W7AY has made similar observations. 73, Rich VE3KI ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
