Logbook of The World
ARRL's electronic QSL verification service for amateur radio awards.
Logbook of the World (LoTW) is an online database run by the American Radio Relay League (ARRL) that lets amateur radio operators verify contacts with each other. Hams use it mainly to earn credit for operating awards like DXCC. Before LoTW launched in 2003, operators had to mail paper QSL cards to the ARRL—a slow and pricey process.
To use LoTW, an amateur must obtain a cryptographic key from the ARRL. The ARRL issues these keys to operators listed in the U.S. FCC database or to non-U.S. hams who can prove their identity another way. Once a ham has a key, they sign their computer logbook (in ADIF or Cabrillo format) using the ARRL’s TrustedQSL program or an equivalent. The signed file is then uploaded to the ARRL server and added to the database.
The system automatically compares log records. When both operators in a contact—at the same time, frequency band, and mode—have submitted matching logs, a confirmation (called a QSL) is created. This matching is blind: neither station can see pending confirmations before uploading their own record. The QSL is purely electronic, though users can print a record of each confirmed contact with its LoTW record number.
Registered amateurs can log into the LoTW website to view their logged contacts and confirmed QSLs. Once they have enough LoTW confirmations (or traditional paper QSLs), they can apply for ARRL awards. As of January 2012, LoTW credit was accepted for awards from both the ARRL and CQ Magazine. The ARRL does not recognize other web-based QSL systems, such as eQSL, for award credit.
As of May 26, 2022, the LoTW server published its own statistics. All registered users can access the main site at lotw.arrl.org. The TrustedQSL software for certificate management and log signing is available at www.arrl.org/logbook-of-the-world, with versions for Windows, Mac, and Linux. Programmers can find source code and design specs from 2001 at trustedqsl.sourceforge.net. Many amateur radio logging programs integrate LoTW functions to simplify signing and uploading.
On May 16, 2024, the ARRL announced it was responding to a “serious incident involving access” to its network and headquarters systems, which made LoTW unavailable. One source described the incident as a cyberattack.
- Started operation
- 2003
- As of may 26 2022
- server statistics available
- 2024 network access incident date
- May 16, 2024
- Supported operating systems
- Windows, Macintosh, Linux
- Key software
- TrustedQSL
- Award credit recognized by
- ARRL and CQ Magazine (as of January 2012)
Lore & Background
Logbook of the World began operation in 2003, replacing a slower and more expensive paper QSL card process for claiming award credit. The system uses secure authentication via cryptographic key distribution; an amateur's computer-based logbook in ADIF or Cabrillo format must be signed using a key obtained from ARRL. ARRL assigns such keys to amateurs who appear in the U.S. FCC licensing database or to non-US amateurs who provide alternate proof of identity.
Once a log file is signed using ARRL's TrustedQSL (or equivalent) program, it is uploaded to the ARRL server and entered in the database. Log records are automatically compared so that when a contact at a particular time, operating mode, and frequency band is claimed by both participating amateurs, a QSL confirmation is declared. The matching process is blind, meaning neither station can see pending confirmations before uploading a matching record. The LoTW QSL is purely electronic, though participants can print a record of each confirmed contact with its LoTW record number.
On May 16, 2024, the ARRL announced it was responding to a 'serious incident involving access' to its network and headquarters-based systems, resulting in LoTW access being unavailable. According to one source, the incident is of a cyberattack nature.
Reader's Guide
Logbook of the World is significant as a centralized, automated electronic verification system that replaced the traditional paper QSL card process for amateur radio award claims. By using cryptographic signing and blind matching, it provides a secure and efficient method for hams to confirm contacts without mailing physical cards. As of January 2012, LoTW credit could be used for awards issued by the ARRL and by CQ Magazine, though the ARRL does not recognize other web-based QSL systems such as eQSL for awards credit. The system is integrated into many amateur radio logging software packages, simplifying the signing and upload process. Its legacy includes reducing the time and expense of award applications, while the 2024 network access incident highlighted vulnerabilities in the infrastructure. The availability of TrustedQSL software for multiple operating systems and open-source code at trustedqsl.sourceforge.net has encouraged community involvement and third-party development.
Did You Know?
- LoTW began operation in 2003.
- On May 16, 2024, a serious network access incident made LoTW unavailable, reportedly due to a cyberattack.
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