IC-R8600 FSK (RTTY) Decoding

Summary: How to decode FSK (RTTY) signals on the IC-R8600, log them to the SD card and change the decoding settings.

Decoding

The receiver has a built-in FSK (RTTY) decoder. In FSK mode, open MENU, DECODE for the FSK DECODE screen, where decoded characters appear.

1. On the FUNCTION screen set the mark frequency and shift (TONE/SHIFT).
2. Rotate the MAIN DIAL to adjust the waveform on the FFT scope until it’s symmetrical and the peaks line up with the mark and shift lines. Tune until both “<” and “>” show in the tuning indicator.
3. If it won’t decode correctly try FSK-R (reverse). Amateur band: use mark 2125 Hz and shift 170 Hz in FSK-R.
4. The baud rate (BAUD key) toggles between 45 and 50 bps. The mark and shift differ by band.

FSK Decode Screen Keys

<1>/<2> switch menus. HOLD/CLR (hold to clear text), TIME (insert a time stamp), ADJ (threshold level; DEF for 1 second resets), EXPD/SET (expanded screen; hold for FSK DECODE SET), BAUD, LOG and LOG VIEW.

Twin Peak Filter (TPF)

In FSK mode, multi-dial, TPF: boosts the mark and space frequencies for better reception (the audio may get louder).

Tone and Shift Settings

On the FUNCTION screen touch TONE/SHIFT:

• FSK RX Frequency (Mark/Space Center): Mark (Space) or Mark/Space Center.
• FSK Tone Frequency (1615 Hz): 1275, 1500, 1615 or 2125.
• FSK Shift Width (170 Hz): 170, 200, 425, 800 or 850.

Logging

Insert an SD card first. MENU, DECODE, <1>, LOG, Decode Log, ON; a red dot shows while logging. Choose the file type, Text (default) or HTML (can’t be changed while logging), and view files in LOG VIEW (the file being logged can’t be viewed). Log files are in the card’s Decode > Fsk folders (.txt or .html).

FSK DECODE SET (EXPD/SET for 1 second)

FFT Scope Averaging (OFF; 2-4), FFT Scope Waveform Color, Decode USOS (ON: unshift on space), Decode New Line Code (CR, LF, CR+LF or CR+LF only), Time Stamp (Time) (Local or UTC), Time Stamp (Frequency) (ON), Font Color (Receive) and Font Color (Time Stamp).

Output to a PC

For RTTY software on a PC, send the decoded data over USB: SET, Connectors, USB (Front) or (Rear), Serial Function = FSK Decode, with the baud rate (4800, 9600, 19200 or 38400 bps; default 9600). See IC-R8600 USB, LAN, CI-V & Remote Control.