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Communications Modes

FBSAT59 includes a full suite of digital communication decoders and encoders for amateur satellite modes.

Overview

Access via Communications menu (between Radio and Autotrack/Record). Each mode opens as a closeable tab.

Mode Purpose SDR / Rig Status
APRS Position beacons & messaging Both Active
Telemetry Satellite sensor data Both Active
SSTV / SSDV Image reception SDR / Rig audio Active
FT4 Weak-signal digital Both Active
Q65 EME (Moon bounce) SDR / Rig audio Active
CW Decoder Morse code detection SDR Active

APRS (Automatic Packet Reporting System)

Receive amateur radio position reports and telemetry from satellites.

Receiving APRS

  1. Communications → APRS
  2. Select a satellite (ISS, JO-97, etc.)
  3. View received packets in real-time
  4. Received positions appear as cyan ▲ pins on the Dashboard map

APRS Data Captured

  • Callsign and SSID
  • Latitude / Longitude
  • Altitude, speed, heading
  • Comment text

Transmitting APRS

Send position beacons or messages:

  1. Enter your callsign in Settings
  2. Click [Transmit Position]
  3. Radio PTT activates automatically
  4. Position beacon sent via AFSK modulation

Telemetry

Decode binary telemetry frames from amateur satellites.

Two Receive Modes

Bell 202 AFSK (Built-in)

1200 baud Bell 202 demodulator: - Works with SDR or rig audio - Supports 12+ satellites with built-in format definitions (ISS, JO-97, RS-44, etc.) - Raw hex display for unlisted satellites

gr-satellites (Optional)

Advanced demodulator supporting 330+ satellites: - Install via Communications → Help → gr-satellites Installation - Automatic format detection - Full telemetry parsing

Satellite Telemetry

Typical decoded data: - Battery voltage - Temperature readings - Solar panel current - Transmitter status - Beacon counter

SSTV / SSDV (Image Reception)

Receive images transmitted by amateur satellites.

Supported Formats

  • SSTV modes: Robot36, PD120, Martin, Scottie
  • SSDV packets: Compressed image transmission (ISS, CubeSats)

How to Receive

  1. Communications → SSTV/SSDV
  2. Tune to satellite transmitter:
  3. ISS SSTV: 145.800 MHz (FM/narrow)
  4. Example CubeSat: 437.550 MHz
  5. Watch for image to build in real-time

FT4 (Weak-Signal Digital)

Encode/decode FT4, a digital mode for satellite QSOs.

Decoding

  1. Tune radio to satellite FT4 downlink frequency
  2. Communications → FT4
  3. Decoded messages appear in real-time

Transmitting FT4

  1. Set radio to uplink frequency
  2. Select your callsign and message
  3. Click [Transmit]
  4. Radio PTT activates automatically
  5. QSO logged (ADIF export available)

Supported satellites: RS-44, JO-97, MO-122, others

Q65 (EME / Moonbounce)

Earth-Moon-Earth weak-signal mode for long-distance satellite QSOs.

Unique Features

  • Ultra-weak-signal reception capability
  • Doppler freeze during transmission (prevents frequency drift)
  • QSO state machine (IDLE → CALLING → EXCHANGE → CONFIRM → LOGGED)
  • Submodes A–E with periods 15/30/60 seconds

Operation

  1. Communications → Q65
  2. Tune to satellite EME downlink
  3. Select submode and period
  4. Monitor signal strength & status
  5. Transmit when ready

Note: Q65 requires significant antenna gain and clear path to moon. Research EME before attempting.

CW Decoder (AI-Powered)

Automatic Morse code detection using deep learning.

Features

  • Recognizes CW/CW-R transmissions automatically
  • Works with both SDR and rig audio
  • Real-time decoding (20-second rolling buffer)
  • Supports typical satellite CW speeds (10–30 WPM)

How to Use

  1. Communications → CW Decoder
  2. Tune radio to CW downlink
  3. Watch decoded text appear in real-time

Installation: - First use downloads ONNX model automatically - ~15 MB download (one-time)

Help & Library Installation

Direwolf (AFSK Modem)

For APRS/Telemetry reception via rig audio:

  1. Help → Direwolf Installation
  2. Auto-detects system installation
  3. Install if missing (Linux/macOS/Windows)

gr-satellites (Advanced Telemetry)

For 330+ satellite telemetry formats:

  1. Help → gr-satellites Installation
  2. Follow platform-specific instructions
  3. gr-satellites subprocess auto-launches on demand

Q65 Library

For EME weak-signal decoding:

  1. Help → Q65 Library Installation
  2. Downloads pre-built libq65
  3. TX encoder (Python) doesn't require library

UDP Log Broadcasting

Optionally broadcast QSO logs to external programs (wavelog, GridTracker, etc.):

  1. File → Settings → Logging
  2. Enable "UDP Log Broadcast"
  3. Set destination: 127.0.0.1:2333 (or remote IP:port)
  4. One ADIF record per confirmed QSO sent over UDP

Compatible with: - wavelog-gate - JT-Linker - Custom log relay tools

Next Steps