The Icom IC-7300 has become one of the most popular HF transceivers for FT8, FT4, JS8Call, and other digital modes. One of its biggest advantages is that it includes both a USB sound card and CAT control over a single USB cable, eliminating the need for external interfaces.

If you’re using WSJT-X on macOS, this guide walks through a proven configuration that delivers reliable CAT control, clean audio, and excellent decoding performance.

What You’ll Need

Before getting started, you’ll need:

Icom IC-7300
USB A-to-B cable
macOS computer
WSJT-X installed
Silicon Labs CP210x USB drivers
HF antenna capable of operating on your desired bands

Once connected, the radio should appear as both:

USB Audio Codec
Silicon Labs CP210x USB to UART Bridge

Install the USB Driver

Install the Silicon Labs CP210x USB to UART Bridge VCP Driver.

This driver allows WSJT-X to communicate with the radio for CAT control.

After installation, your serial port should appear similar to:

/dev/cu.SLAB_USBtoUART

Configure WSJT-X

Radio Settings

Open File → Settings → Radio.

Use the following settings:

Setting	Value
Rig	Icom IC-7300
Serial Port	`/dev/cu.SLAB_USBtoUART`
Baud Rate	115200
Data Bits	Eight
Stop Bits	Two
Handshake	None
PTT Method	CAT
Mode	Data/PKT
Split Operation	Rig

After configuring, click:

Test CAT
Test PTT

Both buttons should turn green.

Audio Settings

Open the Audio tab.

Select the IC-7300’s built-in USB audio device for both:

Input
Output

No additional audio interface is required.

Waterfall Settings

These settings provide excellent FT8 decoding performance.

Setting	Recommended
Bins/Pixel	4
Start Frequency	200–300 Hz
N Avg	2
Palette	Digipan (or your preference)
Cumulative	Enabled
Flatten	Off
Ref Spec	Off
Spectrum	Around 30%

Leave most sliders centered except the upper-right level control, which can be adjusted to match your preference.

Keep the Power slider at 100%.

Configure the IC-7300

Switch the radio to:

USB-D

This ensures the radio uses the correct digital audio path.

Filter Width

Use the widest filter available.

3.6 kHz

A wide filter allows the entire FT8 passband to be visible.

Disable Audio Processing

Digital modes require clean, unprocessed audio.

Turn OFF:

AGC
Noise Reduction (NR)
Noise Blanker (NB)
Auto Notch
Manual Notch
Speech Processing
VOX
Preamps (unless absolutely needed)

These features can distort received and transmitted digital signals.

Display Configuration

A useful display layout is:

Waterfall
Meter

This allows you to monitor:

Signal strength
ALC
Output power
SWR

while operating.

Connector Menu Settings

Navigate to:

MENU
→ SET
→ Connectors

Configure:

Setting	Value
ACC/USB Output Select	AF
ACC/USB AF Output Level	10–30%
ACC/USB AF SQL	Off
ACC/USB AF Beep	Off
ACC/USB IF Output Level	50%
ACC Mod Level	50%
USB Mod Level	40%
Data Off Mod	MIC, ACC
Data Mod	USB

The AF Output Level may require small adjustments depending on band noise and operating conditions.

CI-V Settings

Navigate to:

SET
→ CI-V

Recommended values:

Setting	Value
CI-V Baud Rate	Auto
CI-V Address	94h
CI-V Transceive	ON
USB Remote Address	00h
CI-V Output	Off
CI-V Baud Port	Unlink from REMOTE
USB Baud Rate	115200
USB Echo Back	ON
USB Serial Function	CI-V

These settings provide reliable CAT communication with WSJT-X.

USB Keying

Leave all USB keying options disabled except:

Inhibit Timer

This prevents conflicts during transmit.

macOS Audio MIDI Setup

Open:

Applications
→ Utilities
→ Audio MIDI Setup

Select:

USB Audio Codec

Adjust both:

Left Channel
Right Channel

to approximately:

-9 dB

This is only a starting point.

Your goal is to achieve proper ALC on the radio.

Setting the Correct ALC

One of the most common mistakes in FT8 operation is overdriving the transmitter.

Watch the IC-7300’s ALC meter while transmitting.

Ideally:

ALC should move slightly.
Approximately half to three-quarters of the ALC scale is a practical target based on this configuration.
Avoid driving the meter deeply into the red, which can produce distorted signals.

If necessary:

Reduce WSJT-X output power.
Lower the USB Audio Codec output level.
Adjust the USB Mod Level in the radio.

Verify Your Signal

After configuring everything:

Make a CQ on FT8.
Monitor your transmission.
Check reception reports.
If possible, listen to yourself using a nearby WebSDR.

A clean FT8 signal should have:

Minimal ALC compression
No splatter
Stable transmit power
Good decode reports

Troubleshooting

WSJT-X won’t connect to the radio

Verify the CP210x driver is installed.
Confirm the serial port is /dev/cu.SLAB_USBtoUART.
Check the baud rate (115200).
Make sure no other application is using the CAT port.

No waterfall activity

Verify the USB Audio Codec is selected as the input device.
Confirm the radio is in USB-D mode.
Ensure the squelch is open.

No transmit

Verify PTT Method is set to CAT.
Click Test PTT.
Confirm Data Mode is USB.

Distorted transmitted signal

Reduce WSJT-X power.
Lower USB audio output.
Monitor the ALC meter.
Disable any audio processing such as compression, NR, or NB.

Final Thoughts

The Icom IC-7300 is one of the easiest HF radios to configure for digital modes thanks to its integrated USB sound card and CAT control. With the settings above, you’ll have a solid foundation for operating FT8, FT4, JS8Call, and many other digital modes using only a single USB cable.

As with any digital-mode setup, small adjustments may be needed to match your station, antenna, and operating environment. Once dialed in, the IC-7300 is capable of outstanding performance with reliable decoding, clean transmitted audio, and excellent weak-signal results.

Whether you’re chasing DX, participating in contests, or simply exploring digital communications, this configuration provides a dependable starting point for getting the most out of your IC-7300.

Icom IC-7300 FT8 and Digital Modes Setup Guide for WSJT-X (macOS)