[RTTY] Funny you should mention.....

[Bill Turner]

This whole argument over AFSK vs FSK is really nonsense. Both terms, as commonly used by us hams are FSK, plain and simple. How one generates FSK is technically interesting but not relevant to the signal that goes out over the air. There are probably a dozen or more ways to do it, but the resulting signal that goes over the air is FSK, period.


The acronym AFSK has been misused by hams for so long I have no hope of ever correcting it, but perhaps some folks might be interested in knowing what it REALLY refers to.

The original meaning of AFSK was a carrier, modulated by two tones. It could be either AM or FM, but it was definitely not the FSK we know today, nor was it SSB modulated by two tones. It was a carrier with either AM or FM sidebands. It was NOT a simple carrier which shifted back and forth between two frequencies, as we all use on HF today. 


In fact,FM-AFSK is still in use on VHF packet even now. AM-AFSK might still be in use somewhere but I haven't heard it in ages. And you will not hear either one on the RTTY sub bands on HF because both would be illegal. 


I realize I'm swimming against the tide, but I thought you might want to know. 

Back to the argument. 


73, Bill W6WRT