RTTY, that is, “Radioteletype”, is a way to transmit digital signals upon the radio. It can be considered as one of the first wireless digital transmissions, somehow a predecessor of wireless Internet. Its transmission rate is quite low (something like 60 characters per minute), but it uses a solid modulation, meaning that the signal can be decoded also with high values of noise and interference.
The programme I use for decoding RTTY transmissions is MMTTY, up to know the only free software I found. Then I plug the line-out of my receiver to the mic-in of my laptop to get the signal.
Here follows a list of sub-bands used by radioamateurs transmitting in RTTY, as suggested by AA5AU on his wonderful page Getting Started on RTTY. Usually transmission is at 45.45 baud (60 wpm) and 170 Hz shift for the two tones (2125 and 2295 Hz).
|10 meters||28080 to 28100 kHz|
|12 meters||24910 to 24930 kHz|
|15 meters||21080 to 21100 kHz|
|17 meters||18100 to 18110 kHz|
|20 meters||14080 to 14100 kHz|
|30 meters||10120 to 10150 kHz|
|40 meters||7025 to 7050 kHz|
|80 meters||3580 to 3600 kHz|
|160 meters||1800 to 1820 kHz|
|DDH47||147.3 kHz||50 baud/85 Hz||05.00 – 22.00 UTC|
|DDK2||4583 kHz||50 baud/450 Hz||00.00 – 24.00 UTC|
|DDH7||7646 kHz||50 baud/450 Hz||00.00 – 24.00 UTC|
|DDK9||10100.8 kHz||50 baud/450 Hz||00.00 – 24.00 UTC|
|DDH9||11039 kHz||50 baud/450 Hz||05.00 – 22.00 UTC|
|DDH8||14467.3 kHz||50 baud/450 Hz||05.00 – 22.00 UTC|
RTTY resources on the net: