Setting up CAT/CI-V and Audio Drivers for WSJT-X (2023)

A number of people have had difficulty setting up their radios using the USB interface for WSJT-X and FT-8. It helps to have a basic understanding of the computer interface within the radio. The good news is Kenwood, Icom, Yaesu and even SignaLink share a similar architecture, often down to the same device part numbers and software drivers.

Once the USB cable is connected to the radio the first device in the data path is a USB Hub. Just like a Hub, you might use on your desk its function is to provide multiple USB ports with only one cable from the PC or Laptop. It does not require configuration or drivers and is transparent to the user.

There are two devices connected to the Hub inside the radio. They are a USB UART Bridge and an audio CODEC. If there wasn’t an internal Hub each of these devices would have a separate USB cable to the PC. This is important as it shows how separate and independent they are when setup, access, and drivers are considered.

Kenwood, Icom, and Yaesu use a USB UART Bridge from the SiLabs CP210X family. (SignaLink does not have a serial CAT interface). All three plus SignaLink use a USB/CODEC from the Ti PCM290XB family.

We will review the functions and setup of the USB UART Bridge first.


A “Bridge” may sound complicated but all this device does is accept bi-directional USB and produces bi-directional serial data. It is a bridge between USB and serial data.

(Video) Icom IC-7700 Setup for FT8, FT4 using WSJT-X, USB Audio Adapter Sound Card with SPDIF Digital Audio

You may have used an adapter with a USB connector on one side and a DB-9 9 pin serial connector on the other side. It is likely it used the Silabs CP2101 or a similar device made by FTDI. This interface is often referred to as a Virtual Com Port (VCP) which replaced “real” DB-9 Com ports found on computers into the 1990s. It is called virtual because much of the serial COM port functionality is achieved with software.

The radios that can be computer controlled have a CAT interface (computer-aided transceiver). A related term is CI-V (Communication Interface v5) which is an Icom standard that defines the messages the radio will respond to. The messages are in text (ASCII) format, for example, to transmit you would write TX; to the radio. With a serial interface or VCP, you can send ASCII text messages to your radio using Hyperterminal or an application called PuTTY and it will respond.

Older radios used a CAT interface that required a serial COM Port on the PC. Most of the current radios can still accept serial data through an ACC (accessory port), and a few still have a DB-9 9 pin connector for serial data. Newer radios also have a USB interface and use the USB UART Bridge to receive the serial CAT/CI-V messages from the PC. A radio menu setting is used to select data over an ACC or the USB for radio control.

Audio is not passed using the USB UART Bridge CAT/CI-V interface, it is strictly used for radio commands.

WSJT-X uses a small set of messages over the CAT interface to control the radio. These include band changing, VFO frequency, PTT and a few others.

The USB UART Bridge requires a VCP driver that must be installed by you before connecting the radio to the PC. If you connect the USB cable before installing the driver Windows may locate and install a driver, this works less often than auto-correct in spell check. Once the wrong driver is installed it can be very difficult to uninstall. The correct driver can be downloaded from the radio manufacture’s website.

Once the driver is properly installed and the radio connected the driver can be found in the Windows Device Manager as shown in Figure 1. Note the COM Port number, you will need it to configure WSJT-X. Your COM port number will probably be different.

(Video) WSJT-X Combined with Ham Radio Deluxe using CI-V Cable

Setting up CAT/CI-V and Audio Drivers for WSJT-X (1)

By right clicking on the driver and selecting properties and then the Ports tab you can set the Baud rate, Parity, Stop Bits, and flow control as seen in Figure 2.

Typical settings are as follows:

Baud Rate: 9,600 (Standard values from 9,600 to 115,200 can be used)
Parity: none
Stop Bits: 1 (7300 or 590S/SG 1 or 2 can be used, older rigs and SignaLink with a CP2101 must use 1)
Flow control: Hardware

The settings you select in Device Manager Properties must be used in the WSJT-X setup.

Once these settings are set for the COM port and in the WSJT-X app consider them set, and leave them. If you have completed these steps and do not have CAT/CI-V control of the radio it is due to incorrect radio settings, a bad/cheap cable, you are connected through an unpowered Hub, or are using the front panel USB port of a PC. (Front panel USBs are hit and miss).

Yaesu radios have an additional USB UART Bridge accessible through the hub. You will see an Enhanced port for CAT and a Standard port for PTT in Device Manager. Each has a unique COM port number. WSJT-X has a spot for a second COM address in Settings/Radio for “PTT Method”.The Standard port COM address and RTS is entered for PTT Method.I have used these setting for an FT-991 and FTDX-3000.

CAT is selected for PTT for Icom and Kenwood radios, a second COM address is not used.

(Video) WSJT-X Setup Configurations for Multiple Radios


The second device on the Hub’s output is a CODEC. The CODEC decodes the digitized audio on the USB to analog using an ADC, and using a DAC the analog audio from the radio is digitally coded to be sent to the PC over the USB. Taken together with CODEC COdes and DECodes audio signals from a digital format.

There are no COM port addresses, baud rates, stop bits, etc for you to set since it is not a VCP, it is a standard USB interface.

A PCM290x CODEC is used in the IC-7300, TS-590S/SG, FT-991, SignaLink, and others. The driver is included with Windows XP through 10 so there is nothing for the user to install. Once the CODEC has a USB connection and power it will automatically be installed and set up. The CODEC will appear in Windows Device Manager under “Sounds, Video, Game Controller” when power is applied to the radio. It can be seen in Figure 3 as “USB Audio CODEC”. If there is more than one and you are not sure which one is the radio’s disconnect the USB cable and see which one disappears and then reappears when reconnected.

If the driver has been used with multiple radios it may appear as “3-USB Audio CODEC” or similar which is not a problem provided the same exact label as seen in Device Manager appears in WSJT-X and the Windows Sound settings.

The audio CODEC was identified as “USB Audio CODEC” in the device manager, WSJT-X, and was the selected Input and Output device in the Windows Sound Setting as seen in Figure 4.

Note: The label “microphone” has been replaced with “Line” for PCM290XC rev C CODECs used in the TS-890, other recently released radios, and when a CODEC is replaced due to failure.

(Video) ICOM IC-7300 / WSJT-X FT8 Latest 2021 Setup Guide V1.4 or Higher


Knowing there is a Hub and two independent USB devices in the radio should help when setting up a radio for WSJT-X. The first device is a USB to Serial converter supporting CAT/CI-V, the second device is a USB to Audio CODEC supporting audio input and output.

You will not resolve audio issues by changing the USB UART Bridge settings for baud rate or the number of stop bits. Similarly changing the audio I/O devices is not going to solve a CAT/CI-V problem.

I was surprised to learn the driver we install is only a generic USB UART Bridge. I expected a large complex proprietary composite driver that handled the CAT/CI-V and the audio CODEC. The audio CODEC driver is a standard Windows product.

I have identified the various switches on the radio’s circuit boards and their related menu functions. An example is the switch and menu item that connects the audio I/O from the radio’s processor to the ACC port, Microphone, or the CODEC. I plan to do a separate article on this topic.

In the interim knowing, there are two independent devices should help demystify the menu settings a bit. Baud rate, USB for CI-V, Echo on, etc are for the CAT using the SiLabs USB UART Bridge. Audio I/O levels, Modulation source, and related options only apply to the USB CODEC.

This article may seem a bit bottoms up. It was written from the vantage point gained while troubleshooting and then replacing Hubs, bridges, CODECs and surrounding devices in numerous radios. USB is the most fragile interface on the radio when lightning is a factor….these are the parts at the end of the USB cable.

(Video) Icom IC-7700 Setup Data Modes for FT8 using WSJT-X and RS-BA1


How do you use WSJT-X for FT8? ›

First thing timing make sure that your computer has an appropriate time synchronization program

How do you add frequency to WSJT-X? ›

WSJT-X expects your sound card to do its raw sampling at 48000 Hz. To ensure that this will be so when running under recent versions of Windows, open the system's Sound control panel and select in turn the Recording and Playback tabs. Click on Properties, then Advanced, and select 16 bit, 48000 Hz (DVD Quality).

What is the latest version of WSJT-X? ›

Latest General Availability (GA) releases: WSJT-X 2.5.4

On Windows platforms, WSJT-X 2.5 also includes MAP65 3.0.

What is FT8 digital mode? ›

The FT8 digital mode is the latest in a series of weak signal applications for amateur radio. Conceived originally for enhancing esoteric propagaint modes such as high speed meteor scatter and moonbounce, Joe Taylor (K1JT) developed a series of applications including FSK144, JT6M, JT65, and JT9.

How Much Power Should I run on FT8? ›

Maybe you should run 5 watts until you get the hang of FT8. After say 1 month up that to 10 watts for 6 months. After that go all the way to 50 watts if your rig is rated at 100 w.

What frequencies are used for FT8? ›

Frequencies3.573 MHz,7.074 MHz,10.136 MHz,14.074 MHz,24.915 MHz,50.323 MHz,70.1 MHz,144.174 MHz,1.84 MHz,18.1 MHz,21.074 MHz,28.074 MHz,50.313 MHz
Frequency Range1.84 MHz - 144.174 MHz
7 more rows
14 Apr 2021

What are the Wspr frequencies? ›

Frequencies136 kHz,474.2 kHz,1.8366 MHz,3.5686 MHz,7.0386 MHz,10.1387 MHz,14.0956 MHz,21.0946 MHz,50.293 MHz,70.091 MHz,144.489 MHz,1296.5 MHz,18.1046 MHz,24.9246 MHz,28.1246 MHz,432.3 MHz
Frequency Range136 kHz - 1296.5 MHz
7 more rows
17 Nov 2020

How do I add 60m to Wsjt? ›

If you want to add a suggested working frequency then go to "Settings->Frequencies", right-click in the body of the of the Working Frequencies table, and press "Insert ...". When operating on 60m please take great care to observe and comply with your local licence requirements.

How do I use Wspr? ›

WSPR - An Introduction for Beginners | WSJT-X Ham Radio - YouTube

What is the best software for FT8? ›

WSJT-X is the most popular software for FT8. This great program is not only free but versions are available for Windows-based PCs and Macintosh OS, Linux (with pre-compiled Debian, Fedora and Raspbian distros). For details on installing and configuring the software, follow the online WSJT-X User Guide.

How long has FT8 been around? ›

FT8 was introduced in July 2017 with version 1.8 of the software package WSJT-X [1, 2]. It quickly gained world-wide popularity, by some measures soon accounting for a large fraction of all ham radio activity on the high frequency (HF) bands [3].

What does WSJT stand for? ›

WSJT-X is a computer program designed to facilitate basic amateur radio communication using very weak signals. The first four letters in the program name stand for “Weak Signal communication by K1JT,” while the suffix “-X” indicates that WSJT-X started as an extended and experimental branch of the program WSJT.

Is FT8 upper or lower sideband? ›

But FT8 is an extremely narrowband mode, around 50 Hz wide. In the case of 40M, you set your radio to upper sideband (yes, upper, even on 40M and 80M) and tune it to 7074 kHz.

What is the most popular ham radio digital mode? ›

when hams worked out techniques of connecting mechanical Teletype keyboard/printers to amateur gear using FSK and AFSK modulation. There are too many different modes to list individually, but here are some of the major ones: FT8 - In 2018 it is by far the most popular digital mode for award chasing and working DX.

Does FT8 require Internet? ›

– A Question of Timing. However the criticism of FT8 requiring an Internet connection is a bit different. Most weak signal modes require synchronization of computer clocks to a time standard. Typically, this is done over the Internet.

What is the difference between FT8 and FT4? ›

FT8 messages are transmitted using eight-tone continuous-phase frequency shift keying (CPFSK). Each transmitted tone or channel symbol conveys three bits. FT4 modulation uses four-tone CPFSK at approximately 23.4 baud, with tones separated by the baud rate so each channel symbol conveys only two message bits.

Is Sstv USB or LSB? ›

Slow-Scan Television (SSTV)
Frequencies3 MHz,450 MHz
Frequency Range3 MHz - 450 MHz
ACFLine per minute
7 more rows
6 Feb 2022

Where can I find RTTY signals? ›

RTTY signals can be found on all HF bands - check the band plans and tune through the "Digital Modes" segments. A number of different modes are used in these band segments, but these modes can be distinguished by ear: RTTY signals are characterised by a regular shifting back and forth between two tone frequencies.

What is the bandwidth of a Wspr signal? ›

WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Transmissions carry a station's callsign, Maidenhead grid locator, and transmitter power in dBm. The program can decode signals with a signal-to-noise ratio as low as −28 dB in a 2500 Hz bandwidth.

What is the purpose of WSPR? ›

Introduction. WSPR (pronounced “whisper”) stands for Weak Signal Propagation Reporter. WSPR implements a protocol designed for probing potential propagation paths using low-power transmissions. Normal transmissions carry a station's callsign, grid locator, and transmitter power in dBm.

What does WSPR stand for? ›

WSPR or as it is pronounced, “Whisper” is a software set that is used for weak signal communication between amateur radio stations. In fact the letters WSPR stand for Weak Signal Propagation Reporter.

What frequencies are used for FT4? ›

As initial guidelines we suggest the following default dial frequencies for FT4: 3.595, 7.090, 10.140, 14.140, 18.104, 21.140, 24.919, 28.180, 50.318, 144.170 MHz.

Can WSPR track planes? ›

WSPR technology can be used to detect and track aircraft. This paper underpins the flight path report published 31st December 2021 which provided the findings every two minutes during the entire flight of MH370 from 7th March 2014 16:42 UTC to 8th March 2014 00:20...

Which of the following frequencies might I find a Wspr signal? ›

A WSPR signal is 6 Hz wide. A typical voice channel would be around 2,500 Hz. This allows the tiny WSPR of power to be more concentrated and much more effective. Low bandwidth also limits the signaling rate.

What is FST4 mode? ›

FST4 is optimized for two-way QSOs, while FST4W is for quasi-beacon transmissions of WSPR-style messages. FST4 and FST4W do not require the strict, independent time synchronization and phase locking of modes like EbNaut. The new modes use 4-GFSK modulation and share common software for encoding and decoding messages.

Can technicians use FT8? ›

In addition to SSB on 10M, Techs can also work digital modes including RTTY, PSK, and FT8.

What are the psk31 frequencies? ›

PSK31 Frequencies
FrequencyAmateur Band
7.040 MHz*40 meter (regions 1)
7.070 MHz*40 meter (regions 2)
10.142 MHz30 meter
14.070 MHz20 meter
12 more rows

Is ham radio still alive? ›

Start Your Broadcasting Journey Today. Ham radios are still relevant in 2021. Whether you're studying for your FCC license or you're interested in taking up a new hobby, investing in an amateur radio is a worthwhile pursuit.

How wide is a CW signal? ›

(T8A05) The approximate maximum bandwidth required to transmit a CW signal is 150 Hz.

What is Wsjt in ham radio? ›

WSJT, Weak Signal communication by K1JT is a form of digital communication mode optimised for weak signal amateur radio communication. WSJT was originally developed by K1JT around 2000 / 2001 but now the software is open source and its development is continuing under the management of a small team of radio amateurs.

Is FT8 allowed on field day? ›

Q. Can I operate FT4/FT8 for Field Day? A. All digital modes can be used during Field Day, provided they can accommodate the Field Day exchange.

What is winlink ham radio? ›

Winlink, or formally, Winlink Global Radio Email (registered US Service Mark), also known as the Winlink 2000 Network, is a worldwide radio messaging system that uses amateur-band radio frequencies and government frequencies to provide radio interconnection services that include email with attachments, position ...

What is grid tracker? ›

GridTracker integrates with many popular logging programs and web based systems, allowing you to see up to the minute progress for awards. Complete DXCC, Country, Callsign Prefix recognition. 100% offline mode available for field-day, SOTA, IOTA and/or mobile use.

Can technicians use FT8? ›

In addition to SSB on 10M, Techs can also work digital modes including RTTY, PSK, and FT8.

What mode is SSTV? ›

Like the similar radiofax mode, SSTV is an analog signal. SSTV uses frequency modulation, in which every different value of brightness in the image gets a different audio frequency. In other words, the signal frequency shifts up or down to designate brighter or darker pixels, respectively.

What is ham DMR? ›

DMR ham radio is an open standard radio network optimized through efficient bandwidth use via Time-Division Multiple Access. TDMA divides communication into time slots, which ensures the senders and receivers can communicate uninterrupted in two separate conversations without changing the frequency.

What is PSK31 in ham radio? ›

PSK31 is a highly-efficient data mode that lets you work long distances, even when you can barely hear the signal. PSK31 stands for Phase Shift Keying 31 baud (or 31 bits per second/bps). Unlike RTTY (radio teletype) the characters are formed by changing the phase of the sound wave, not by using different tones.


(Prof.Dr. İsmail Çakmak)
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