Saturday, March 16, 2013

A rant about RTTY

I just worked Iraq for the first time. YI1RZ on 20m using JT9-1 mode.

What was remarkable about this QSO is that I worked YI1RZ despite the presence of heavy RTTY QRM. My Elecraft K3 has great filtering but it can do nothing about a RTTY signal that is straddling the QSO frequency.

Why, in this age of DSP, do people persist in using this antiquated mode? Dating from the 1930s and the age of mechanical teleprinters and analog modems, RTTY is by any definition an outmoded mode. It requires far too much power and occupies far too much bandwidth for the data transmission rate (45 baud.) PSK31 has existed for more than a decade and is a far more efficient mode. If PSK31 is too slow then there is PSK63 which is faster than RTTY and yet still manages to occupy less bandwidth. Not to mention the plethora of other modes such as MFSK and Olivia that have been invented in the last 10 years offering far greater reliability than RTTY and, like PSK, the ability to use the entire character set not just capital letters, numbers and a few punctuation symbols. And which don't print up garbage because a shift character wasn't decoded.

It feels good to get that off my chest! I'd better put my asbestos suit on! It is interesting to note that as I have been typing this WSJT-X has been pulling JT9-1 out of the air in the teeth of RTTY interference so great that you cannot even see the JT9-1 signal traces. JT9 rocks! I doubt if the RTTY operators even know the JT9-1 signals are there.
Post a Comment