Mastering QSO Logging: Cabrillo and ADIF Formats Made Simple

If you’re serious about ham radio contesting or exchanging logs with other operators, mastering Cabrillo and ADIF formats is essential. These formats are the standard used for submitting contest entries and exchanging data between logging programs. While they serve different purposes, both require attention to detail to ensure your logs are accurate, complete, and accepted without issue. Let’s break it all down so you can breeze through your next contest submission or log exchange!

Cabrillo Format: QSO Logging for Contests

Cabrillo is the go-to format for submitting contest logs. It’s standardized, easy to read, and designed specifically for contest sponsors to verify your contacts. But don’t let its simplicity fool you—getting it right takes some care and maybe a little extra time.

• Header Section: This is where you include key information about your station and the contest. It’s like a cover letter for your log. A typical header includes call sign, contest name, operating category, claimed score, and your contact information. See example below:
  
  START-OF-LOG: 3.0
CALLSIGN: W1AW
CONTEST: ARRL-DX-CW
CATEGORY: SINGLE-OP ALL LOW
CLAIMED-SCORE: 125000
NAME: Hiram Maxim
ADDRESS: 225 Main Street
ADDRESS: Newington, CT 06111
  
  
• QSO Records: Each contact gets its own line, formatted precisely to include: date and time, frequency or band, mode (CW, SSB, etc.), sent and received exchanges, and callsign of station
  
  QSO: 14025 CW 2025-03-01 2100 W1AW 599 CT G3XYZ 599 DX QSO: 7025 CW 2025-03-01 2115 W1AW 599 CT DL1ABC 599 DX QSO: 3500 CW 2025-03-01 2130 W1AW 599 CT JA1XYZ 599 DX
  
  
• End Marker: Finish the file with END-OF-LOG:. Example: END-OF-LOG:

Pro Tip: Use your logging software’s Cabrillo export feature, but always double-check the output for accuracy. Contest sponsors often provide sample files; compare yours to ensure compliance.

ADIF Format: Versatility for Logging QSOs

While Cabrillo is tailored for contesting, ADIF (Amateur Data Interchange Format) shines in day-to-day QSO logging and exchanging logs with other hams. It’s supported by virtually all modern logging software and is ideal for importing/exporting data.

ADIF is a widely recognized standard for sharing logbook data among amateur radio operators and logging software. At its core, ADIF is a plain-text file format that structures QSO (contact) data in a consistent and predictable way. This makes it incredibly useful when transferring log entries between programs or submitting logs to services like LoTW, eQSL, or contests. Each ADIF file consists of a header, where metadata such as the software version or operator’s callsign can be noted, followed by individual QSO records. These records are made up of key fields enclosed in angle brackets, followed by the value for each field. Think of it as a tidy recipe card for each contact, allowing any compatible software to “read the ingredients” with ease.

Key fields in an ADIF record include essential details about each QSO. For instance, the CALL field stores the callsign of the station you contacted, while BAND specifies the frequency band (e.g., 40m or 20m). The MODE field captures how you communicated, like CW, SSB, or FT8, and QSO_DATE and TIME_ON indicate when the contact was made. For award tracking or log integrity, fields like RST_SENT and RST_RCVD record signal reports exchanged during the QSO. Optional fields like GRID_SQUARE or OPERATOR add even more depth, especially for contests or specialized logging needs. The beauty of ADIF lies in its simplicity and flexibility—it provides a universal language for logging data, ensuring that your QSO records remain accessible and compatible no matter what software or service you use.

Key Points for ADIF Logs:

1. File Structure: ADIF files consist of headers and records. Each record details a single QSO, encapsulated in tags like <CALL>, <BAND>, and <MODE>. Example: <CALL:5>G3XYZ <BAND:3>20M <MODE:2>CW <QSO_DATE:8>20250301 <TIME_ON:6>210000
   
2. Mandatory Fields: Ensure these core tags are present:
   • <CALL>: Callsign of the station worked
   • <QSO_DATE>: Date of the contact in YYYYMMDD format
   • <TIME_ON>: Time in HHMMSS (UTC)
   • <BAND> or <FREQ>: Band or frequency
   • <MODE>: Operating mode
     
3. Optional but Useful Fields:
   • <RST_SENT> and <RST_RCVD>: Signal reports
   • <NAME>: Operator’s name
   • <QTH>: Location
     
4. Header Information: Begin with an ADIF version header, like: ADIF_Version: 3.0 Created_By: YourLoggingSoftware 1.0
   

Avoid including unsupported or incorrect tags. Most software validates ADIF files, but it’s wise to verify manually or use an online ADIF checker if in doubt. A popular online validator is K1MU Rick’s online ADIF file validation tool.

Common Pitfalls to Avoid when Logging QSOs

• Time Zones: Always log in UTC. Forgetting this is a common mistake that will get your file rejected.
• Formatting Errors: Even a small typo can cause issues. Double-check line breaks, tag spelling, and spacing.
• Missing Exchanges: Incomplete logs may lead to disqualifications in contests. Triple-check your sent/received data and which fields are required for your contest.

Tools to Make Life Easier

• Cabrillo Validators: Many contest sponsors provide online tools to validate your Cabrillo files. Use them!
• ADIF Editors: Free tools like ADIFMaster or online services can help you clean up your ADIF files.
• Logging Software: Popular programs like N1MM Logger+, Ham Radio Deluxe, and Log4OM handle most of the heavy lifting.
  

Whether you’re gunning for the top spot in your favorite contest or simply sharing logs with fellow hams, clean and accurate log files are your ticket to success. Cabrillo and ADIF might seem daunting at first, but with a bit of practice and attention to detail, you’ll find them straightforward and incredibly powerful.

73 and good luck!

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