CCIR493 4

This mode is used for individual and group selective calling on the HF bands. The data consists of short bursts of 100 baud FSK (Frequency Shift Keying) with a shift of 170 Hz. Rivet decodes this data and displays it so it looks like this ..

12:53:51 CCIR493-4 Individual Selective Call Station 2522 Calling 2519 (Routine)

CCIR493-4 data can either be decoded live from a HF radio connected to your soundcards line in input or from a prerecorded WAV file. This WAV file however must be recorded in mono mode with a 8000 Hz sample rate.

To decode this mode tune your radio to the frequency where you know CCIR493-4 is used with the receiver set to either USB or LSB modes. Rivet will wait for the brief CCIR493-4 synchronisation sequence and adapt itself from that then decide if the signal needs to be inverted or non-inverted automatically.

There is a WAV file recording of a CCIR493-4 signal on the Rivet sound samples page here.