In reality you are probably right. Those of us who have primarily been RTTY'ers for the past 20+ years have come to associate afsk with badly setup signals, double signals, splatter, etc.
I have (blindly) been holding out for FSK but after a braindropping from Mr. Bickle (wasn't he the Extension Agent on Green Acres?) I have come to the conclusion its just old analog thinking. It probably doesn't matter where the shifting occurs, because its going to be clean and filtered. Also, being able to see your signal on the PSDR panadapter keeps you pretty safe from overdriving it. Neal Campbell Abroham Neal Software Programming Services for Windows, OS X and Linux www.abrohamnealsoftware.com (540) 242 0911 On Fri, Feb 6, 2009 at 6:06 PM, Brian Lloyd <brian-wb6...@lloyd.com> wrote: > > On Feb 6, 2009, at 1:49 PM, Rick Markey, KN3C wrote: > >> Ditto on the requests for true FSK. I love my 5K but have held off >> setting >> it up for RTTY because of the lack of FSK. I ran true FSK on my Drake B >> line and my Kenwood 850 and 870. You just can't beat it. The lack of FSK >> is probably the only thing I find lacking in the Flex. > > Perhaps you can enlighten me. Why would FSK in a later oscillator be better > than FSK in an earlier oscillator? > > Back in the good ol' days FSK was better because you were FM'ing a > high-stability oscillator. AFSK had to suffer with the noise and > nonlinearity of the audio path to the first balanced mixer. The audio chain > between mic jack and first balanced mixer usually wasn't all that good. It > certainly wasn't HiFi. ;-) > > But with the F5K, that isn't an issue. When you use a digital mode program > connected to PowerSDR using VAC, you are actually doing FSK. You are just > doing it in an earlier stage, i.e. in your first DSP stage (the digital mode > program). You also have all the advantages of being able to do waveform > shaping for sideband control. Therefore the quality of the emitted signal > generated inside your digital-mode program as "AFSK" will be as good or > better than what you can generate by FM'ing an analog BFO in your Drake. > There just isn't any good reason to try to do FSK of the DDS LO in the F5K. > > -- > > 73 de Brian, WB6RQN/J79BPL > Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com > > > > > > _______________________________________________ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flex-radio.com/ Homepage: > http://www.flex-radio.com/ > _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
