On Feb 15, 2009, at 2/15 8:58 AM, Guy Olinger, K2AV wrote: > Taking the DATA A readings below at face value, the more than 2 db > bump > around 1000 Hz is rather startling. I'm not sure what could cause > that, but > at least to me that seems to be screaming for an explanation. > There's an > old fireman's adage "never go past fire" to keep from being trapped > by fire > closing around behind.
While I agree that a 2 dB bump is really, really bad for us guys who use frequency-agile digital transmission, this phenomenon is not restricted to just the K3. The FT-1000MP has a similar 3 dB peak when you select PKT (i.e., AFSK); and, like the K3, the rig is flat when using voice SSB modes. In the case of the FT-1000MP, it appears to be a deliberately designed peaking -- the peak is "centered" near the AFSK tone pair that you have selected to use. To see the FT-1000MP's variability, you can look at the following URL http://homepage.mac.com/chen/w7ay/cocoaModem/UsersManual/ UsersManual.html#equalizer Scroll below the two control panels and you will see the graphical display of the variability. (In this program, you enter the measured power in that second column on the left, and the program splines the "curve" to produce the power correction that is applied to the transmitted signal when you "click on the waterfall.") 73 Chen, W7AY ______________________________________________________________ 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
