Digital Modes
The Evolution of Digital Modes in HF Since 2020 by 30AT048 George
Since 2020, digital modes in HF have undergone unprecedented growth, becoming one of the most widely used forms of long-distance communication in amateur radio. While digital operation was already well established during the previous decade, advances in software development, signal processing, computer integration, and weak-signal decoding have accelerated adoption to levels few could have predicted.
The undisputed driving force behind this evolution has been FT8. Developed by Joe Taylor (K1JT) and the WSJT-X development team, FT8 was already highly popular in 2020, but during the following years it became the dominant digital mode on the HF bands. Its ability to decode signals far below the noise floor has enabled reliable worldwide contacts using modest antennas and very low power levels. As a result, thousands of operators who previously struggled with challenging propagation conditions gained access to consistent long-distance communications.
The period from 2020 onward has also seen increased interest in digital modes designed for actual operator-to-operator communication rather than standardized signal exchanges. Among these, VARA HF has become one of the most widely used protocols for efficient data transfer and radio-based email systems. Equally important is JS8Call, a communication platform derived from FT8 technology that allows free-text messaging, message storage and forwarding, station networking, and emergency communications.
Digital innovation has not been limited to the amateur HF bands. The 11-meter band (27 MHz / CB Radio) has experienced remarkable growth in digital activity during the same period, driven both by favourable propagation conditions associated with Solar Cycle 25 and by the development of software specifically adapted to CB operation. Modes such as JS8, FT8, VARAC, SSTV, and ROS have attracted increasing numbers of operators, allowing long-distance contacts to be completed under challenging signal conditions.
One of the most significant milestones in this field has been the creation of WSJT-CB, a project led by 1AT106 Lorenzo "Vash". Built upon the foundation of WSJT-X, WSJT-CB is far more than a cosmetic modification. The software introduces code-level adaptations designed specifically for 27 MHz operation, including native support for CB-style identifiers, integrated 11-meter operating frequencies, improved handling of non-amateur radio callsigns, and numerous refinements intended to make FT8 and FT4 operation more practical and intuitive within the CB community.
The development of WSJT-CB has enabled thousands of 11-meter operators to participate in modern digital communications using tools specifically tailored to their operating environment. The project has fostered the growth of an international digital community on 27 MHz, encouraging the creation of awards programs, activity events, logging initiatives, and coordinated operating groups. As a result, digital modes have evolved from a niche activity within CB radio into a visible and growing segment of worldwide 11-meter operation.
The emergence of WSJT-CB has also been accompanied by several historic achievements within the international CB community. Among them, the Alfa Tango International DX Group became the first organization to activate a DXpedition using modern digital modes from Mount Athos under the callsign 254AT/0, demonstrating the viability of digital operations from one of the rarest and most sought-after DX entities on 11 meters. Building on that success, Alfa Tango also organized what is widely recognized as the first major 11-meter DXpedition to make extensive use of FT8, operating from Timor-Leste under the callsign 341AT/0. These pioneering operations showcased the potential of weak-signal digital communications on 27 MHz and contributed significantly to the expansion and acceptance of FT8 within the global CB community.
Another important trend during this period has been the increasing integration of radio stations with advanced computer systems. Logging software, electronic confirmation platforms, propagation monitoring networks, SDR technology, and real-time reporting services have transformed the way operators interact with the HF spectrum. Modern digital stations are now capable of collecting and analyzing vast amounts of propagation data while maintaining efficient communications under conditions that would have been considered extremely challenging only a decade ago.
Overall, the period from 2020 to 2026 can be regarded as the spread of these technologies into the 11-meter band, particularly through initiatives such as WSJT-CB and the pioneering efforts of the Alfa Tango International DX Group, demonstrates that digital experimentation continues to attract new operators and drive innovation across the broader radio communication community.
Digital Modes on 11 Meters (27 MHz)
The following frequencies are commonly used by the international 11-meter digital community and are promoted by the Alfa Tango International DX Group.
Recommended 11-Meter Digital Frequencies
These frequencies are widely recognized within the international digital activity community on 11 meters and are used daily by operators worldwide.
FT8 (27.265 MHz)
Software
WSJT-X (Official)
WSJT-CB (11-Meter Edition)
Developed by 1AT106 Lorenzo "Vash", WSJT-CB is a specialized version of WSJT-X adapted for CB and 11-meter operators, with native support for CB-style callsigns and dedicated 27 MHz operating frequencies.
Manuals
JS8 (27.245 MHz)
Software
JS8Call
JS8Call is based on FT8 technology but allows free-text messaging, store-and-forward communication, and network-oriented operation.
Manuals
SSTV (27.700 MHz)
Software
MMSSTV (Windows)
QSSTV (Linux)
EasyPal
ROS (27.635 MHz)
Software
Created by EA5HVK José Alberto Nieto, ROS was one of the first digital modes specifically embraced by the 11-meter community due to its excellent weak-signal performance.
Download:
Manuals
VARAC (27.195 MHz)
Software
VarAC
VarAC is a modern chat-oriented digital communication application built around the VARA modem. It supports keyboard-to-keyboard conversations, file transfers, emergency communications, and messaging services.
Requirements
VARA HF Modem
VarAC provides extensive documentation in multiple languages:
Communities
PSK31 (27.500 MHz)
Software
FLDIGI
MultiPSK
Manuals
RTTY
Software
FLDIGI
MMTTY
Manuals
If you need help/support with digital modes you can contact us at 30 (at) 048.es
Since 2020, digital modes in HF have undergone unprecedented growth, becoming one of the most widely used forms of long-distance communication in amateur radio. While digital operation was already well established during the previous decade, advances in software development, signal processing, computer integration, and weak-signal decoding have accelerated adoption to levels few could have predicted.
The undisputed driving force behind this evolution has been FT8. Developed by Joe Taylor (K1JT) and the WSJT-X development team, FT8 was already highly popular in 2020, but during the following years it became the dominant digital mode on the HF bands. Its ability to decode signals far below the noise floor has enabled reliable worldwide contacts using modest antennas and very low power levels. As a result, thousands of operators who previously struggled with challenging propagation conditions gained access to consistent long-distance communications.
The period from 2020 onward has also seen increased interest in digital modes designed for actual operator-to-operator communication rather than standardized signal exchanges. Among these, VARA HF has become one of the most widely used protocols for efficient data transfer and radio-based email systems. Equally important is JS8Call, a communication platform derived from FT8 technology that allows free-text messaging, message storage and forwarding, station networking, and emergency communications.
Digital innovation has not been limited to the amateur HF bands. The 11-meter band (27 MHz / CB Radio) has experienced remarkable growth in digital activity during the same period, driven both by favourable propagation conditions associated with Solar Cycle 25 and by the development of software specifically adapted to CB operation. Modes such as JS8, FT8, VARAC, SSTV, and ROS have attracted increasing numbers of operators, allowing long-distance contacts to be completed under challenging signal conditions.
One of the most significant milestones in this field has been the creation of WSJT-CB, a project led by 1AT106 Lorenzo "Vash". Built upon the foundation of WSJT-X, WSJT-CB is far more than a cosmetic modification. The software introduces code-level adaptations designed specifically for 27 MHz operation, including native support for CB-style identifiers, integrated 11-meter operating frequencies, improved handling of non-amateur radio callsigns, and numerous refinements intended to make FT8 and FT4 operation more practical and intuitive within the CB community.
The development of WSJT-CB has enabled thousands of 11-meter operators to participate in modern digital communications using tools specifically tailored to their operating environment. The project has fostered the growth of an international digital community on 27 MHz, encouraging the creation of awards programs, activity events, logging initiatives, and coordinated operating groups. As a result, digital modes have evolved from a niche activity within CB radio into a visible and growing segment of worldwide 11-meter operation.
The emergence of WSJT-CB has also been accompanied by several historic achievements within the international CB community. Among them, the Alfa Tango International DX Group became the first organization to activate a DXpedition using modern digital modes from Mount Athos under the callsign 254AT/0, demonstrating the viability of digital operations from one of the rarest and most sought-after DX entities on 11 meters. Building on that success, Alfa Tango also organized what is widely recognized as the first major 11-meter DXpedition to make extensive use of FT8, operating from Timor-Leste under the callsign 341AT/0. These pioneering operations showcased the potential of weak-signal digital communications on 27 MHz and contributed significantly to the expansion and acceptance of FT8 within the global CB community.
Another important trend during this period has been the increasing integration of radio stations with advanced computer systems. Logging software, electronic confirmation platforms, propagation monitoring networks, SDR technology, and real-time reporting services have transformed the way operators interact with the HF spectrum. Modern digital stations are now capable of collecting and analyzing vast amounts of propagation data while maintaining efficient communications under conditions that would have been considered extremely challenging only a decade ago.
Overall, the period from 2020 to 2026 can be regarded as the spread of these technologies into the 11-meter band, particularly through initiatives such as WSJT-CB and the pioneering efforts of the Alfa Tango International DX Group, demonstrates that digital experimentation continues to attract new operators and drive innovation across the broader radio communication community.
Digital Modes on 11 Meters (27 MHz)
The following frequencies are commonly used by the international 11-meter digital community and are promoted by the Alfa Tango International DX Group.
Recommended 11-Meter Digital Frequencies
| Mode | Frequency (USB) |
| FT8 | 27.265 MHz |
| JS8 | 27.245 MHz |
| VARAC | 27.195 MHz |
| ROS | 27.635 MHz |
| SSTV | 27.700 MHz |
| PSK31 | 27.500 MHz |
These frequencies are widely recognized within the international digital activity community on 11 meters and are used daily by operators worldwide.
FT8 (27.265 MHz)
Software
WSJT-X (Official)
WSJT-CB (11-Meter Edition)
Developed by 1AT106 Lorenzo "Vash", WSJT-CB is a specialized version of WSJT-X adapted for CB and 11-meter operators, with native support for CB-style callsigns and dedicated 27 MHz operating frequencies.
Manuals
- Official WSJT-X User Guide:
- Full WSJT-X Documentation:
- WSJT-CB User Guide:
- WSJT-CB Telegram Group:
- Alfa Tango Digital Modes Portal:
JS8 (27.245 MHz)
Software
JS8Call
JS8Call is based on FT8 technology but allows free-text messaging, store-and-forward communication, and network-oriented operation.
Manuals
- Official User Guide:
- Spanish User Guide:
- JS8 for 11 Meters Users:
- JS8Call 11 Meters:
SSTV (27.700 MHz)
Software
MMSSTV (Windows)
QSSTV (Linux)
EasyPal
- Available through various amateur radio software repositories.
- SSTV Software Directory:
- SSTV Club 27.700 MHz USB:
- SSTV 27.255 MHz CH23 USB:
- SSTV 11M 27 MHz CB:
ROS (27.635 MHz)
Software
Created by EA5HVK José Alberto Nieto, ROS was one of the first digital modes specifically embraced by the 11-meter community due to its excellent weak-signal performance.
Download:
Manuals
- Official ROS Documentation:
- Technical Information:
- ROS Modem for CB Radio Operators:
- World 11m Band CB ROS Group:
VARAC (27.195 MHz)
Software
VarAC
VarAC is a modern chat-oriented digital communication application built around the VARA modem. It supports keyboard-to-keyboard conversations, file transfers, emergency communications, and messaging services.
Requirements
VARA HF Modem
- Download:
VarAC provides extensive documentation in multiple languages:
- English
- Spanish
- French
- Italian
- German
- Japanese
Communities
- Official Facebook Group:
- Available from the VarAC website
- Official Telegram Group:
- Available from the VarAC website
- Official Website:
PSK31 (27.500 MHz)
Software
FLDIGI
MultiPSK
Manuals
- FLDIGI Documentation:
RTTY
Software
FLDIGI
MMTTY
Manuals
- FLDIGI Documentation:
- MMTTY Documentation:
- Included with the software package.
If you need help/support with digital modes you can contact us at 30 (at) 048.es