[Elecraft] K3 Question: AFSK-A or DATA-A for RTTY?

[James Bennett]

I've been a PSK31 user just about ever since the mode came to be. Not a heavy user, but couple time a month I get on and have some nice keyboard QSO's. In the 50 years that I've been licensed, I have NEVER made a RTTY QSO! However, it does intrigue me so I started messing with it a little this week.

I recently got a new external sound card for my station - a Tascam US125. It is connected to my iMac via USB and the K3 via a pair of stereo cables. Works fine on JT65, JT9, and PSK31. I use WSJT-X for the JT-modes and cocoaModem (CM) for PSK31. CM also provides RTTY so I gave it a shot. After a few burps I got it going.

With PSK31 and the JT-modes, I've always had the K3 in DATA-A setting. RTTY "seems" to work in either DATA-A or AFSK-A. Fred Cady's K3 book states that AFSK-A is "optimized for RTTY". How? What is the real benefit to switching to AFSK-A mode for RTTY? Is that what everyone is using, or is DATA-A just as good?

Thanks, Jim / W6JHB