FT8CN Documentation

FT8CN is a mobile application designed for research purposes to study the decoding and transmission of FT8 signals. It is intended for learning how to operate FT8 signals and is not responsible for any consequences resulting from user operation.

Key Characteristics:

• Lightweight Processing: Due to mobile hardware and battery constraints, the app uses lightweight signal processing instead of deep decoding.
• Compliance: Users must comply with local radio management regulations (e.g., the Radio Management Regulations of the People's Republic of China).

FT8CN provides two decoding modes depending on your requirements for speed versus signal detection capability:

1. Fast Decoding (快速解码): Performs a single-pass decoding on the received audio. This is the standard FT8CN decoding method and is optimized for speed and battery efficiency.
2. Multi-pass Decoding (多次解码): Performs multiple iterations of decoding on top of the Fast Decoding process. This mode attempts to decode signals with overlapping frequencies that might be missed in a single pass.

Warning: Using Multi-pass Decoding increases computational load, which results in longer decoding times and reduced device battery life.

FT8CN implements a 'Launch Supervision' mechanism to balance automation with manual control. Unlike protocols like JT65, which provide longer windows (approx. 10 seconds) for decision-making, FT8 and FT4 protocols have much shorter sequences requiring faster responses.

To prevent full robotic operation while still allowing for necessary automation, FT8CN follows the Joel Taylor philosophy: automation is permitted only to a limited extent. The 'Launch Supervision' system monitors automated processes; if no human intervention occurs within the defined supervision time limit, the transmission program will automatically stop to ensure the operator remains in control.

Automatic CQ Following (自动关注CQ) is a feature where FT8CN monitors decoded messages for CQ calls. When a CQ message is detected, it is automatically pushed to the message list in the "Call" (呼叫) interface. This allows you to react to CQ calls quickly.

Note: CQ messages detected via this automatic mechanism are transient; the callsign is not permanently saved to your long-term "Followed Callsigns" database.

FT8CN features a SWL (Shortwave Listener) mode for recording and exporting decoded messages and QSOs without necessarily participating in a full contact.

SWL QSO Criteria: To be recognized as a valid SWL QSO, the record must contain at least:

1. Reports from both parties.
2. An ending phrase such as 73, RR73, or RRR.

The Auto Call Tracked feature allows you to monitor specific target callsigns. Once a target callsign is set to track, FT8CN will automatically initiate a call to that callsign whenever it exhibits CQ behavior.

Key behaviors:

• Persistence: Tracking callsigns are preserved long-term.
• Notification: Every time a tracked callsign sends a new message, FT8CN pushes it to the "Calling" interface list.
• Unfollowing: To stop tracking a callsign, you must delete it via background operations by accessing FT8CN through a web browser on your LAN.

To protect radio equipment, FT8CN includes monitoring and alerting for Standing Wave Ratio (SWR) and Automatic Level Control (ALC).

Alerting Features:

• SWR/ALC Alarms: Users can enable or disable SWR and ALC alarm switches (v0.93).
• Signal Strength Adjustment: Users can adjust signal strength specifically to regulate ALC levels.

To establish communication between the radio and the app, you must configure the CI-V (Communications Interface V) address and the Baud Rate (data transmission speed).

CI-V Address

The CI-V address is a unique identifier used to distinguish between different devices on the same control line.

• Default Control Address: Typically 0xE0.
• Broadcast Address: 0x00.
• Device-Specific Addresses: Each radio model has a default address (e.g., the IC-705 defaults to 0xA4).

Baud Rate

The Baud Rate defines the data transmission speed between the radio and the app.

Automatic Configuration

The app includes a database of default addresses and maximum supported baud rates for various radio models. You can automatically configure these settings by selecting your specific radio model from the "电台型号" (Radio Model) menu.

To control the instruction set of your radio (RIG) via FT8CN, you must select the specific RIG model you are using from the provided list. Because different brands use different instruction sets, selecting the correct model ensures FT8CN communicates correctly with your hardware.

ICOM Series RIGs

If you are using an ICOM series radio, selecting your model from the list will automatically configure the following settings:

• CI-V address
• Baud rate

Manual Configuration

If your specific RIG model is not present in the selection list, you must manually configure the appropriate CI-V address and baud rate to establish communication.

The application includes robust tools for managing, querying, and exporting contact (QSO) logs.

Log Management Capabilities:

• Import/Export: Support for importing ADI files and exporting logs with specific criteria (v0.88).
• Querying: Logs can be queried by specific conditions and displayed in descending order by time.
• Map Integration: Query results can be located and displayed on a map (v0.87).
• Automated Uploads: Supports automatic log uploading to services like QRZ and CloudLog (v0.93).
• Sharing: Includes a log data sharing function (v0.93).

The app provides automation features to streamline FT8 operations, including automatic calling and filtering of specific signals.

Automation Features:

• Automatic Calling: Can be configured to automatically call specific targets or follow CQ messages.
• Callsign Prefix Exclusion: Users can define callsign prefixes to exclude. This action has the highest priority and will prevent the automatic program from calling those specific prefixes (v0.85).
• Callsign Modifiers: Supports adding modifiers to calls, such as CQ POTA xxxxxx xxxx or CQ DX xxxxxx xxxx. Modifiers can include ranges like 000-999, A-Z, AA-ZZ, AAA-ZZZ, and AAAA-ZZZZ (v0.85).