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Radio Control

FBSAT59 provides comprehensive radio control with automatic Doppler correction, mode selection, and CTCSS tone management — all automatically synchronized with satellite positions.

Overview

The Radio Control tab is the command center for your amateur radio equipment:

Dashboard - Satellite Tracking

  • Downlink (RX) frequency — Automatically adjusted for Doppler shift
  • Uplink (TX) frequency — With per-transponder offset memory
  • Mode — USB, LSB, CW, FM, automatically set for transponders
  • CTCSS/DCS tone — Automatically selected from transmitter database
  • Real-time indicators — Signal strength, lock status, current elevation

Built-in Hamlib Support

FBSAT59 includes Hamlib, the industry-standard amateur radio control library supporting 700+ radio models.

Supported Radios (Examples)

Manufacturer Model Mode Connection
Yaesu FT-991A, FT-857D, FT-817ND All modes USB/Serial
Icom IC-9700, IC-9100, IC-705, IC-7300 All modes USB/LAN
Kenwood TS-2000, TS-890S All modes Serial
Elecraft K3S, KX3 All modes USB
Transceiver Many others Various Check Hamlib docs

Connection Methods

Most modern radios connect via USB serial:

# Linux: Appears as /dev/ttyUSB0 or /dev/ttyACM0
# Windows: COM3, COM4, etc.
# macOS: /dev/tty.usbserial-xxx
  1. Connect radio via USB
  2. Settings → Rig Settings
  3. Select radio model from dropdown
  4. Port auto-detects
  5. Click [Connect]

2. Network (TCP/IP)

For radios on your local network (e.g., Icom IC-9700 with Ethernet):

  1. Settings → Rig Settings
  2. Select "Network (TCP)"
  3. Enter radio IP address
  4. Click [Connect]

3. Rotator Control (Optional)

Control antenna rotator (azimuth/elevation):

  1. Settings → Rotator Settings
  2. Select rotator model
  3. Serial port configuration
  4. Click [Connect]

Both radio and rotator can be controlled independently.

Doppler Tuning

As a satellite moves toward or away from you, its signal frequency shifts (Doppler effect). FBSAT59 automatically calculates and applies Doppler correction.

How It Works

  1. Real-time position — FBSAT59 calculates satellite position every second
  2. Doppler shift — Based on satellite velocity relative to you
  3. Frequency adjustment — Your rig's frequency is automatically updated

Example: When ISS passes over your location: - AOS (Acquisition) — Doppler shifts downlink UP (satellite approaching) - TCA (Closest approach) — Minimum Doppler shift (peak elevation) - LOS (Loss of Signal) — Doppler shifts DOWN (satellite receding)

Doppler Lock

The [L] button toggles Doppler tuning:

  • L (ON) — Frequency updates automatically every second
  • L (OFF) — Fixed frequency (manual tuning only)

Use L (OFF) when: - Testing transmitter response (Doppler can mask frequency errors) - Receiving narrow-bandwidth modes that require stable frequency - Troubleshooting radio connectivity

Transponders & Modes

FBSAT59 displays all available transmitters for the selected satellite:

  • Downlink frequency — What you receive
  • Uplink frequency — What you transmit (if applicable)
  • Mode — FM, SSB, CW, PSK, etc.
  • CTCSS/DCS — Tone/code requirement (if any)
  • Bandwidth — For digital modes
  • Status — Active, inactive, or unknown

Click any transponder to select it. All frequencies and modes update automatically.

Manual Frequency Override

Want to use a custom frequency not in the database?

  1. Right-click transponder → Edit
  2. Modify downlink/uplink frequencies
  3. Save (stored locally, survives app restart)

Advanced Features

Rig 1 + Rig 2 (Dual Radio)

Connect two radios (or one radio + one SDR) simultaneously:

  1. Settings → Rig 1 Settings (first radio)
  2. Settings → Rig 2 Settings (second radio, optional)
  3. Both appear in Radio Control tab

Use cases: - Uplink on Rig 1, Downlink on Rig 2 (split frequency operation) - Backup radio (automatic failover if Rig 1 disconnects) - Simultaneous APRS/Telemetry reception on separate bands

Frequency Preset

When you select a transponder, FBSAT59 automatically writes frequencies to your radio — even before pressing [Connect].

This ensures your radio displays the correct satellite frequencies immediately.

CW Toggle

For SSB/USB/LSB transponders, a CW button appears:

  • Click once → Switch to CW-U (CW Upper Sideband)
  • Click again → Switch back to original mode

Perfect for quick CW/SSB switching without manually selecting modes.

Troubleshooting Radio Connection

"Serial Port Not Found"

  • Check USB cable connection
  • Install FTDI drivers (Windows/Mac): https://ftdichip.com/drivers/
  • Linux: lsusb to verify radio appears

"Radio Model Not Listed"

  • Your radio is supported by Hamlib (700+ models)
  • Search Hamlib documentation for your model
  • Try a compatible model (e.g., "FT-991" if you own "FT-991A")

Doppler Shift Too Aggressive

  • Check TLE age (Help → TLE Status)
  • Outdated orbital elements cause incorrect Doppler calculation
  • Click Satellite menu → Fetch TLE Data to update

Frequency Jitter

  • Radio firmware may limit update rate (some older radios)
  • Try increasing Doppler update interval in Settings
  • Some radios require mode-dependent baud rates

Radio Control Keyboard Shortcuts

Shortcut Action
Ctrl+C Connect to radio
Ctrl+D Disconnect
L Toggle Doppler Lock
T Toggle PTT (Push To Talk)
R Record audio

Next Steps