DECODIUM 4.0 “Shannon” — Quick Start

This guide takes you from zero to your first FT8 and FT2 QSO in the shortest possible time. For full details, see the User Manual.

1. Installation

Windows x64

1. Download Decodium_1.0.262_Setup_x64.exe from the official release
2. Double-click the installer (user-mode, no admin required)
3. The installer automatically cleans caches from previous versions
4. Launch DECODIUM from the Start menu

macOS Apple Silicon (M1/M2/M3)

1. Download the .dmg or .zip file for macOS from the release
2. Open the DMG and drag DECODIUM to the Applications folder
3. First launch: right-click → Open (to bypass Gatekeeper)

Linux x86_64

1. Download Decodium-1.0.262-x86_64.AppImage
2. Make it executable: chmod +x Decodium-1.0.262-x86_64.AppImage
3. Launch by double-clicking or from terminal

Minimum requirements: 4 GB RAM · dual-core CPU · 200 MB disk space · compatible sound card.

2. First launch — Essential setup

On first launch, fill in the minimum required fields:

💡 Tip: For Kenwood TS-590S, set in radio menus: Menu 63 = DATA IN, Menu 64 = USB IN level, Menu 65 = USB OUT level.

Press Test CAT to verify the connection. When you see the green CAT LED at the bottom, you’re ready.

3. Your first FT8 QSO

Band setup

1. From the band toolbar, select 40 (40 meters)
2. The radio automatically tunes to 7.074 MHz
3. Mode: FT8 (default)
4. Press MON to activate audio monitoring

Decoding

After 15 seconds you’ll see the first decodes in the windows: - Full Spectrum (left) — all decodes across the audio band - Signal RX (right) — only the selected frequency - Live Map — world map of received signals

Transmitting

1. Click a station calling CQ in the Full Spectrum
2. Decodium automatically prepares TX1-TX6 messages
3. Press TX or let auto-sequencing run
4. Standard QSO flow completes automatically: CQ → Reply → R+SNR → RRR → 73 → log
5. At end of QSO, press LOG to save to ADIF logbook

⚠️ Important: Before transmitting, verify the PWR level is not excessive. SWR < 2:1 recommended.

4. Your first FT2 QSO

FT2 is DECODIUM’s native mode: 3.8-second T/R cycle, complete QSO in ~6 seconds, sensitivity down to −23 dB SNR with Raptor Engine.

Activation

1. On the mode toolbar, click FT8 → select FT2
2. The radio stays on the same band
3. Press DEEP to activate Raptor Engine (5 passes)
4. Decoding starts within seconds

ASYMX — Asynchronous transmission

ASYMX eliminates Even/Odd synchronization. No NTP, no GPS needed:

1. Click the AP (Async Period) button in the toolbar
2. Async mode activates
3. Transmit whenever you want: the signal is always decodable by WSJT-X/JTDX
4. QSO proceeds like FT8 but in 6 seconds instead of 60+

💡 Tip: ASYMX is ideal for maritime operations, emergency, portable — anywhere internet or GPS is not available.

Quick QSO (QQ)

To accelerate further, activate QQ in the toolbar:

• 4-message flow instead of 5
• Automatic TU detection
• Automatic fallback to classic cycle if the partner station doesn’t support QQ

5. CALL — Direct call (v1.0.262)

The new 📞 CALL button lets you call a specific callsign without waiting for their CQ.

How to use it

1. Click 📞 CALL in the TX toolbar (next to ACQ)
2. The CallDialog opens
3. Enter the target callsign (e.g. F4CQS)
4. Set retries (e.g. 10), timeout (e.g. 60s), period (e.g. every slot)
5. Press ▶ Start
6. Decodium calls F4CQS IU8LMC JN71 at every slot
7. The tooltip shows retry N/M in real time
8. Automatic stop when max retries reached
9. If the target replies → automatic handoff to normal autoSeq flow (R+SNR, RR73, log)

When to use it

• 🎯 Skeds with friends — call directly at the agreed time
• ⚡ Fast replies to missed CQs — you saw the decode but clicked too late
• 🏝️ Targeted DXpedition activations — repeated calls on a rare station

6. What to do if something doesn’t work

CAT won’t connect

• Check baud rate (TS-590S: 57600 recommended)
• Try different COM ports (Device Manager on Windows)
• Temporarily disable OmniRig or HRD if conflicting
• Press Test CAT after each change

No decodes

• Check audio IN level: green bar at 30-50% (in Audio settings)
• Correct band? Standard FT8 frequencies = 7.074 (40m) · 14.074 (20m)
• Time sync: top of screen shows 00:04:53.978 UTC — if red, sync your PC clock
• Filters: try disabling FDR if active

PTT won’t fire

• PTT mode: CAT, VOX, RTS, DTR? Check Setup → PTT
• If RTS/DTR: ON = high, OFF = low, empty = don’t force
• Test with TUNE button (generates test tone)

Empty Live Map

• Check internet connection
• Decodium downloads paths only when valid decodes occur
• Wait at least 30 seconds after the first decode

7. Resources

• 🌐 Official site: https://ft2.it
• 📥 Downloads: https://github.com/iu8lmc/Decodium-4.0-Core-Shannon/releases
• 📖 Full User Manual: coming soon
• 💬 Telegram community: link on ft2.it
• 🐛 Bug reporting: GitHub Issues

73 de Martino IU8LMC & Salvatore 9H1SR DECODIUM / FT2 Team — ARI Caserta · Italy · GPLv3