Radio control with CAT and PTT in the browser
Many transceivers can be remote-controlled via USB or a serial port. Signal-Pirat sets frequency and mode, reads them back and keys the transmitter – right in the browser, without a driver program. A virtual radio shows everything before a real radio is connected.
Open in the browser
No installation, no sign-up needed.
What the page does
- Command sets Icom CI-V, Kenwood and newer Yaesu radios (text CAT)
- PTT via CAT or via the RTS and DTR control lines
- Set and continuously read frequency and mode
- Live signal search shows the RF frequency of each signal and tunes the radio on request
- Transmit only after confirming your licence, with callsign and time limit
- Command log for troubleshooting, virtual radio for practice
Background
CAT (Computer Aided Transceiver) is remote control of a radio by a computer. Icom's CI-V uses binary frames: two preamble bytes FE, the radio's address, the computer's address E0, command, data and the end byte FD. The frequency is five BCD bytes, lowest digits first – 14.074 MHz becomes 00 40 07 14 00. Kenwood and newer Yaesu radios use text commands with a semicolon, such as FA00014074000; for Kenwood and FA014074000; for Yaesu. In the browser the connection uses the Web Serial interface, currently available in Chrome, Edge and Opera on a computer.
In practice
How it works: connect the radio via USB, look up the CAT or CI-V baud rate and, for Icom, the address in the radio's menu, and choose the same values in Signal-Pirat. When connecting, the browser asks which port may be used. Frequency and mode then appear. For the transmit key, confirm your licence and enter your callsign; the radio transmits only while the key is held. Also enable the radio's own time-out timer.
Frequently asked questions
Which radios are supported?
Radios with Icom CI-V, Kenwood text CAT or the text CAT of newer Yaesu radios. Older Yaesu radios with 5-byte commands are not supported. Control has not yet been tested with real radios; reports on individual models are welcome.
Why does it not work in Firefox or Safari?
These browsers do not offer the Web Serial interface. The virtual radio still works everywhere.
Is my callsign stored?
No. It only unlocks the transmit key and stays in the open page.