FT991(A) Link is an advanced computer program designed for amateur radio operators using transceivers Yaesu FT-991 and FT-991A. Its goal is to provide full-featured and comfortable control of the radio via CAT interface, eliminate some shortcomings of the original TRX firmware and at the same time add many useful features that are missing in the radio itself.
Connection to the radio and basic concept of FT991(A) Link
The program allows connection to the radio either via COM port, or via USB interface. The author recommends using USB cable, as it ensures the only connection:
CAT radio control
sound card function (RX/TX audio)
For proper operation, it is necessary to select in the radio Enhanced port and set the correct communication speed (Baud Rate):
item 029 for RS232C cable
item 031 for USB cable
Recommended communication speed is 38400 bps.
Main window of the FT991(A) Link program
The main window of FT991(A) Link provides full control of the radio including:
switching bands, modes and VFO
working with memory channels
complete access to the TRX menu
A great advantage is the possibility to save the radio menu to a file and later reload it back. During menu editing, it is possible to change the communication speed - the program will automatically adapt to it.
If the USB cable is disconnected, the program will notify about it in the status bar. Upon reconnection, parameter reading will automatically resume.
Audio functions and signal analysis
The program supports receiving audio from the radio to the computer. The user has available:
listening to RX audio on PC
display spectrum of the audio signal
measurement CTCSS tone
signal analysis using cursors directly in the graph
One of the most interesting features is quick detection of CTCSS tone – takes approximately 0.1 seconds and works both in the main window and in a separate RX Audio window.
Recording received stations
FT991(A) Link allows automatic recording of received stations:
recording starts after opening the squelch
is tied to the SQL function
records shorter than 1 second are not saved
Files are saved in the format WAV, in folders named by date. The file name includes:
date and time of the start of the recording
frequency
channel name (if available)
mode
signal level
CTCSS tone
Records can be quickly viewed using the button "Show".
Fixes and new features of FT991(A) Link
The program author has resolved several known issues of the FT-991/991A transceivers, such as:
unwanted frequency changes when switching modes
issues when switching between VFO and memories
At the same time, it added new, very practical features. When scanning memory channels the program displays the last received frequency or channel name, which the radio itself does not allow.
System notifications
The program can display System notifications with information about the currently received station. This feature is disabled by default and can be enabled in the menu by the item "Show RX notification".
Memory channels - complete management
FT991(A) Link offers full programming of memory channels:
display of all memories at once
switching, adding, deleting, and editing
functions cut, copy, paste, delete (menu or shortcuts)
option to save memories to a file and later upload them back to the radio
import memories from the program Win4Yaesu
Memories marked in orange color are excluded from scanning.
TX equalizer and microphone signal processing
By clicking the button "TX Equalizer" a window will open with detailed settings for the transmission audio chain:
equalizer graph (processor on/off)
bandwidth setting for SSB
turning on/off the processor and equalizer
shaping of the microphone characteristic
finished filters with the option to save and load from a file
Synchronization and other tools
The program menu has the function available:
synchronization of radio date and time with PC
saving user callsign
recording the current location
Settings encoder is activated by the button next to the displayed RX frequency. If CTCSS and DCS are off, the button shows the status ENC OFF.
Semi-REV function
Since CAT commands for FT-991(A) do not contain a direct command for the button REV, the author added a software function Semi-REV. This allows listening to the input frequency of the repeater:
works only within the program
behaves the same as REV on the radio
requires setting offsets for individual bands
Default values:
2 m: 0.6 MHz
70 cm: 7.6 MHz
Settings are available via the button S next to Semi-REV.
Appearance and compatibility FT991(A) Link
The program supports:
light and dark mode (dark mode from Windows 10 and above)
interface scaling
The author recommends dark mode, which is pleasant for the eyes and well-readable.
FT991(A) Link is 32-bit application and has been successfully tested on systems Windows XP to Windows 11.
Development, support, and availability
The program is continuously developed and may contain errors. The author welcomes problem reports and suggestions for improvements - the contact email is provided in the menu "Info/Update".
The program is always available:
as installer
or as ZIP version without installation
Downloading is checked by Google antivirus. Links to the latest version, screenshots, and changelog are available in the section Info/Update, as well as on storage sites:
Conclusion
FT991(A) Link by Dariusz SP4UBW is an exceptionally successful tool that significantly expands the capabilities of transceivers Yaesu FT-991 and FT-991A. It offers comfortable CAT control, detailed memory management, advanced audio features, signal analysis, and a number of practical improvements that every active radio amateur will appreciate - whether in daily operation or when working through repeaters and scanning memory channels.