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RadioLog › Manual › 03 · CAT Control

03 · CAT Control

Connecting your radio, VFO control, modes and relay for external programs

What is CAT?

CAT (Computer Aided Transceiver) allows RadioLog to control your radio from the computer: reading and changing frequency, mode, band and other parameters without touching the physical controls. It also lets WSJT-X and other programs share control without port conflicts.

Configuring the CAT Connection

Go to Settings → CAT to configure the connection with your radio.

CAT section in Settings
Redesigned in v3.4.0 The Settings → CAT page now uses a two-column layout: a CAT Method dropdown at the top switches between three connection methods, with the matching fields shown below. Advanced serial options are grouped in a collapsible section.

The Three CAT Methods

MethodRecommended forRequires
Direct RadioLog CAT controlYaesu FT-991A, FTDX10, FT-710… and native Icom CI-VJust the USB/serial cable of the radio
Hamlib managed by RadioLogYaesu FT-817/817ND, FT-818, FT-857/857D, FT-897/897DJust the USB/serial cable — Hamlib is bundled, nothing to install
External rigctld serverAny of the 500+ radios Hamlib supports, or an existing rigctld you already runA separately running rigctld process

Method 1 · Direct RadioLog CAT control (recommended for Yaesu and Icom)

  1. Connect the radio to the PC via USB (the cable included with the radio).
  2. Windows installs drivers automatically. Note the COM port number (e.g. COM3) in Device Manager.
  3. In Settings → CAT: set CAT Method to Direct RadioLog CAT control.
  4. Choose the Manufacturer and Radio model. For Icom CI-V radios, a CI-V Address (hex) field appears automatically.
  5. Choose the COM port (use the ↺ button to rescan serial ports) and the correct baud rate.
  6. Optionally tick Connect CAT on startup.
  7. Save the configuration, then connect from Radio → Connect CAT.
Model and COM port selection in Settings → CAT

Baud rates by Yaesu model

ModelBaud rate
FT-817 / FT-8189600
FT-991 / FT-991A38400
FTDX10 / FTDX10138400
FT-710 AESS38400
FT-DX5000115200
CAT port vs PTT port Modern Yaesu radios with USB create two COM ports: one for CAT and one for PTT/Enhanced. RadioLog uses the CAT port (generally the lower number). The PTT port is used by WSJT-X for RTS in digital modes.

Method 2 · Hamlib managed by RadioLog (new in v3.4.0)

RadioLog now includes Hamlib 4.7.2 itself — there is nothing to download or install separately. When you connect, RadioLog launches its own rigctld process in the background for the selected radio and stops it when you disconnect or close the app.

  1. In Settings → CAT: set CAT Method to Hamlib managed by RadioLog.
  2. Choose your radio from the Radio model dropdown. Initial support covers:
    • Yaesu FT-817 / FT-817ND
    • Yaesu FT-818
    • Yaesu FT-857 / FT-857D
    • Yaesu FT-897
    • Yaesu FT-897D
  3. Choose the COM port and baud rate as usual — the radio is still connected by serial cable, RadioLog just talks to it through its internal rigctld.
  4. Save and connect from Radio → Connect CAT. RadioLog starts rigctld automatically, restricted to 127.0.0.1 (never exposed to the network) and picks a free TCP port on its own — no port number to configure.
Support in progress Hamlib support for the radios above is being validated progressively. If something doesn't behave as expected, sending your radiolog.log file helps complete the validation.

Method 3 · External rigctld server

Use this method for any Hamlib-supported radio not yet in RadioLog's managed list (Icom, Kenwood, Elecraft, Flex Radio and 500+ others), or if you already run your own rigctld for other software.

Installing Hamlib on Windows

  1. Download from github.com/Hamlib/Hamlib/releases the file hamlib-w64-X.X.X.zip.
  2. Extract to C:\Hamlib\.
  3. Check in CMD: C:\Hamlib\bin\rigctld.exe --version

Starting rigctld with your radio

# Icom IC-7300 — COM3, 9600 baud
rigctld -m 3073 -r COM3 -s 9600

# Icom IC-7610 — COM3, 9600 baud
rigctld -m 3078 -r COM3 -s 9600

# Kenwood TS-890S — COM3, 115200 baud
rigctld -m 2044 -r COM3 -s 115200

# Elecraft K3 — COM3, 38400 baud
rigctld -m 2029 -r COM3 -s 38400

# Find your model:
rigctld --list

Configuring RadioLog to use it

  1. In Settings → CAT: set CAT Method to External rigctld server.
  2. Host: localhost | Port: 4532 (or whatever your rigctld is using).
  3. Make sure rigctld is running before connecting. RadioLog only acts as a client — it never starts or stops this rigctld.
  4. Connect from Radio → Connect CAT.
Don't point it at RadioLog's own relay RadioLog also runs its own rigctld-compatible relay for WSJT-X (see below). If the host/port here matches that relay, RadioLog rejects the connection to avoid connecting to itself.

Control Window: Radio → RigControl

Once CAT is connected, open Radio → RigControl for the real-time radio control panel: frequency, mode, VFO-A/B, band and connection status.

RigControl window with VFO and mode in real time

CAT Relay for WSJT-X and Other Programs

When RadioLog is connected to the radio, it automatically acts as a rigctld server (Hamlib NET rigctl) on TCP port 4532. WSJT-X, JTDX, FLDigi and any Hamlib-compatible program can connect to RadioLog without conflict — RadioLog is the sole owner of the serial port.

Configuration in WSJT-X:

Radio configuration in WSJT-X pointing to RadioLog relay

Problem: WSJT-X moves the wrong VFO

Symptom: Changing frequency in WSJT-X moves VFO-B instead of VFO-A (or vice versa).

Cause: On some Yaesu radios (e.g. FTDX10) CAT commands FA/FB don't correspond to the physical VFO-A/B labels.

Solution: Settings → Digital Modes → CAT Relay → ☑ Swap VFO-A/B in relay → Save → Restart RadioLog.

Confirmed on FTDX10 (EA5YC) This setting fixes the problem on the FTDX10 with WSJT-X.
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