Icom IC-7300 + fldigi Setup Guide
Complete setup for Olivia and other digital modes. The IC-7300 is the most popular HF rig for digital modes with its single USB cable providing both CAT control and audio.
Quick Reference
| USB Connection | Type-B (rear panel) - single cable for CAT + audio |
| Rig Control | RigCAT (requires IC-7300.xml) - Hamlib not supported |
| Baud Rate | 19200 (recommended) or 38400 |
| CI-V Address | 94h (default) |
| Audio Device | USB Audio CODEC |
| PTT Method | CAT command (recommended) |
1. USB Connection Overview
The IC-7300 features a single USB Type-B port on the rear panel that provides:
- CAT (Computer-Aided Transceiver) control via virtual COM port
- Audio interface for digital mode operation
- Both functions operate simultaneously over one cable - no separate audio interface required
Key Advantage
Single USB cable eliminates the need for separate audio interface boxes common with older transceivers.
2. Driver Installation
Windows 11
- Before connecting the radio, download and install the official Icom IC-7300 USB driver:
- Visit Icom America Support
- Download the USB driver from the support page
- Run the installer with administrator privileges
- Restart your computer
- The IC-7300 uses a Silicon Labs CP210x USB-to-UART bridge chip. If you need the raw driver:
- Download from Silicon Labs CP210x VCP Driver Page
- CRITICAL: Unplug the USB cable from the radio during driver installation
- After installation, connect the IC-7300 USB cable. Windows will recognize:
- Virtual COM port (for CAT control)
- USB Audio CODEC device (for audio)
macOS
- macOS Big Sur and later have built-in CP210x drivers - no additional installation needed
- macOS Catalina and earlier: Download Silicon Labs CP210x drivers from the link above
Linux
CP210x drivers are built into the Linux kernel. Verify device detection:
ls -l /dev/ttyUSB* /dev/ttyACM*3. fldigi Configuration
Step 1: Download Required Files
- Download fldigi from SourceForge
- Download the IC-7300 rig definition file: IC-7300.xml
- Optional but Highly Recommended: Download flrig for superior rig control
Step 2: Configure RigCAT
Important: The IC-7300 cannot use Hamlib for rig control; you must use RigCAT.
- Launch fldigi
- Go to Configure → Rig Control
- Select the RigCAT tab
- Check "Use RigCAT"
- Click "Open" and select your downloaded IC-7300.xml file
- Set:
- Baud Rate: 19,200
- Device: Select your USB device (appears as "SLAB_USBtoUART" or similar)
- Check these boxes:
- Commands are Echoed
- CAT command for PTT
- Restore Settings on close
- Click "Initialize" to test, then "OK" to save
Step 3: Configure Audio
- Go to Configure → Sound Card
- Select Capture (input): USB Audio CODEC
- Select Playback (output): USB Audio CODEC
- Sample Rate: 44100 Hz or 48000 Hz
- Click OK
4. IC-7300 Radio Configuration
Access these via MENU → SET on the radio.
USB Connectivity (MENU → SET → Connectors)
| Setting | Value | Notes |
|---|---|---|
| USB Serial function | CI-V | Enables CAT control |
| USB MOD Level | 28-40% | Start at 28%; adjust based on ALC meter |
| Data Mod | USB | Routes audio from computer in data mode |
| ACC/USB AF Output Level | 40-75% | Controls audio sent to computer |
CI-V Settings (MENU → SET → CI-V)
| Setting | Value | Notes |
|---|---|---|
| CI-V Address | 94h | Default; do not change unless multi-radio setup |
| CI-V USB Baud Rate | 19,200 | Matches fldigi default |
| CI-V USB Echo Back | On | Optional but recommended |
Mode and Filter Settings
- Select USB-D Mode: Press MODE button for USB, then press DATA button
- Adjust Filter: Long-press FIL1 button, set to 3.0 kHz or wider for Olivia
Disable for digital modes: Compression, Notch Filter, Noise Blanker (NB), Noise Reduction (NR)
Power and ALC Settings
- RF Power Level: Set to 30-40 watts initially (digital modes require less power)
- USB MOD Level: Start at 28%, use fldigi's "Tune" function and monitor ALC
- Goal: ALC should remain at zero or slightly above during transmission
5. Operating with Olivia Mode
fldigi Olivia Configuration
- Click Op Mode (top left menu)
- Navigate to Olivia and select variant (OL 8-250, OL 8-500, etc.)
- Set frequency to 1500 Hz in fldigi (the "sweet spot" for IC-7300)
- Ensure IC-7300 is in USB-D mode with 3.0 kHz or wider filter
Transmitting
- Compose your message in the TX panel
- Click "Tune" to transmit a test tone - monitor ALC (should be at zero)
- Click "TX" to transmit, "RX" when done
6. Common Issues and Troubleshooting
USB Device Not Recognized
- Ensure USB driver is installed before connecting the radio
- Unplug and replug USB cable
- Check Device Manager for unknown devices
- Try different USB ports (avoid USB 3.0 hubs on older systems)
No Audio to/from Radio
- Verify "USB Audio CODEC" selected in fldigi Sound Card settings
- Check radio: Data Mod = USB
- Check USB MOD Level is not too low
- Ensure you're in USB-D mode (not regular USB)
PTT Not Working
- Verify RigCAT is enabled with "CAT command for PTT" checked
- Check that baud rate matches radio CI-V settings (19,200)
- Add ferrite chokes to USB cable if experiencing interference
- Disconnect wireless mice/keyboards (can cause interference)
High ALC During Transmission
- Reduce USB MOD Level in 2-5% increments
- Reduce computer audio volume to 40-50%
- Ensure compression is disabled
- Goal: ALC at zero or minimal during normal transmission
7. Advanced: Using flrig for Enhanced Control
flrig provides superior rig control. Many users prefer using flrig + fldigi combination:
Setup Steps
- Download and install flrig
- Configure flrig: File → Rig Defaults, select Icom IC-7300
- Set XML file path, baud rate (19200), and device
- In fldigi: Configure → Rig Control, select Flrig
- Set port to localhost:12345
- Launch flrig first, then fldigi
Advantage: Cleaner separation of concerns, more responsive rig control, can use flrig's advanced features independently.
8. Recommended Operating Parameters
Transmit Power by Mode
| Mode | Recommended Power | Notes |
|---|---|---|
| PSK31 | 20-30 watts | Low power is sufficient |
| Olivia | 20-35 watts | Can use lower power due to robust modulation |
| RTTY | 30-50 watts | Can tolerate more power |
| JT-65/FT8 | 20-30 watts | Weak signal mode |
Audio Levels (Starting Points)
| Parameter | Setting |
|---|---|
| USB MOD Level (TX) | 28% |
| USB AF Output Level (RX) | 40-75% |
| Computer Output Volume | 50% |
| Transmit Frequency | 1500 Hz |
9. Official Documentation
- Icom America Support Portal - Manuals, drivers, firmware
- fldigi IC-7300 Setup Wiki
- flrig IC-7300 How-to
- G3NRW CI-V Deep Dive (PDF)
Pre-Flight Checklist
- USB driver installed
- IC-7300 connected via single USB Type-B cable
- IC-7300.xml downloaded and selected in fldigi RigCAT
- CI-V Address: 94h, Baud Rate: 19200
- Audio device: USB Audio CODEC
- Radio in USB-D mode with 3.0 kHz+ filter
- PTT test passed (CAT command working)
- ALC at zero during Tune
- Power: 20-35 watts for digital modes