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Logging is the backbone of contesting. Your logging software is not just a record-keeper — it is your real-time scoring engine, duplicate checker, multiplier tracker, and the tool that produces the electronic log you submit after the event. Choosing the right software and knowing how to use it effectively will improve your contest experience immediately.
This page covers the major contest logging programs, the Cabrillo log format, and best practices for accurate, efficient logging.
You might wonder why you cannot simply use a general-purpose station logger for contests. Technically you can, but dedicated contest logging software provides features that make a significant difference during the event:
Real-time duplicate checking. The software instantly tells you whether you have already worked a station on the current band and mode, saving you from wasting time on a contact that will not count.
Automatic scoring. Your score updates with every contact, showing QSO points, multipliers, and total score. This lets you make informed strategic decisions throughout the contest.
Exchange validation. The software knows what exchange the contest requires and flags entries that look wrong — an invalid zone number, a state abbreviation that does not exist, or a serial number out of sequence.
Band map and cluster integration. In the assisted category, your logging software can display DX cluster spots and CW skimmer data on a bandmap, showing you exactly where stations are and which ones you still need.
Cabrillo export. After the contest, you export your log in Cabrillo format — the standard electronic format accepted by virtually all contest sponsors. General loggers often lack this capability.
Rate displays. Logging software tracks your contact rate over time, which helps you evaluate your strategy and identify your most productive operating periods.
Several well-established programs dominate the contest logging landscape. All of them are capable and well-supported — the best choice depends on your operating system, personal preference, and the features you value most.
N1MM Logger+ is the most widely used contest logging program in the world. It is free, open-source, and runs on Windows.
Key features: supports virtually every contest, highly configurable, SO2R support, networked multi-operator capability, integrated voice and CW keyer, extensive bandmap and cluster support, active development community.
Best for: operators who want maximum flexibility and are comfortable with a feature-rich interface. N1MM is the standard against which other loggers are measured.
Win-Test is a high-performance contest logger popular with serious competitors and multi-operator stations, particularly in Europe. It was originally a commercial product and is now freely available.
Key features: fast and lightweight, excellent multi-operator support, advanced SO2R features, built-in voice keyer, sophisticated scoring engine.
Best for: experienced contesters and multi-operator teams who value speed and reliability above all else.
WriteLog is a long-established Windows-based contest logger with a loyal user base. It offers a clean interface and solid feature set.
Key features: easy to learn, good SO2R support, integrated voice keyer, supports most major contests, sound card interface for digital modes.
Best for: operators who prefer a straightforward interface and are primarily interested in phone and CW contests.
SkookumLogger is the leading contest logger for macOS. If you use a Mac, this is your primary option.
Key features: native macOS application, clean interface, supports most major contests, CAT control, CW keyer, Cabrillo export.
Best for: Mac users who want a native contest logging experience without running Windows.
TR4W (TR for Windows) is a free, lightweight contest logger inspired by the classic DOS-era TR Log. It has a minimalist interface that some operators prefer for its simplicity and speed.
Key features: very fast, low resource requirements, keyboard-driven interface, supports major contests, free.
Best for: operators who prefer a no-frills, keyboard-centric workflow.
TLF is a free, open-source contest logger for Linux, designed for console (text-mode) operation. It runs in a terminal and is fully keyboard-driven.
Key features: Linux-native, very fast, works over SSH, CW keyer support, Cabrillo export, active development.
Best for: Linux users and operators who want a lightweight, terminal-based logger.
Regardless of which software you choose, the setup process before a contest follows the same general pattern:
Select the contest. Open the contest module for the specific event you are entering. This loads the correct exchange format, scoring rules, and multiplier definitions.
Enter your station information. Your callsign, entry category, power level, and ARRL section or CQ Zone (as applicable). This information goes into the Cabrillo header.
Configure radio control. Connect your radio via CAT (USB or serial) so the software can read and set frequencies automatically. Test the connection to ensure the software correctly tracks band changes.
Set up function keys. Assign your CQ message, exchange, and common responses to function keys. On CW, the software sends these via the radio's keying input. On phone, configure a voice keyer or sound card interface.
Configure networking (multi-op). If you are operating with a team, set up the network so all computers share a single log. Test this before the contest starts.
Synchronise your clock. Contest log times must be accurate. Use the software's built-in time sync feature to synchronise with an internet time server. Most logging programs do this automatically if you have an internet connection.
Run a practice session. Log a few test contacts to make sure everything works — radio control, function keys, exchange entry, and duplicate checking. Delete the test entries before the contest begins.
Cabrillo is the standard electronic log format for contest submissions. It is a plain-text format that all contest logging software can export. A Cabrillo file contains:
You do not need to edit Cabrillo files by hand — your logging software generates them automatically. But understanding the format helps you spot problems if a submission is rejected:
START-OF-LOG: 3.0
CALLSIGN: N0CALL
CONTEST: CQ-WW-SSB
CATEGORY-OPERATOR: SINGLE-OP
CATEGORY-BAND: ALL
CATEGORY-POWER: HIGH
CATEGORY-ASSISTED: NON-ASSISTED
CLAIMED-SCORE: 1234567
CLUB:
LOCATION: WMA
NAME: Your Name
QSO: 14200 PH 2025-10-25 0001 N0CALL 59 05 G4XYZ 59 14
QSO: 21300 PH 2025-10-25 0003 N0CALL 59 05 JA1ABC 59 25
END-OF-LOG:
Each QSO line follows a fixed column format. The fields are: frequency (in kHz), mode, date, time (UTC), your callsign, your exchange, the other station's callsign, and their exchange.
Contest logs are cross-checked against each other during adjudication. If your log says you worked G4XYZ at 0001 UTC, the contest committee checks G4XYZ's log to see if they have a corresponding contact with you. Errors hurt both stations:
If you are not sure you copied the callsign correctly, ask for a repeat. A moment spent confirming is far better than a penalty during log checking. Most logging software highlights unusual callsigns or warns you if a call does not match expected patterns.
Most contest loggers include a check partial function that shows possible callsign matches as you type. This helps you recognise partially copied calls and reduces errors. The super check partial database draws on historical contest logs to show likely calls — if you type "G4X," it might suggest G4XYZ based on that station's participation in past events.
Enter contacts as you make them, not after the fact. Logging from memory or from paper notes after the contest introduces errors and makes it impossible to have accurate times.
After the contest, take a few minutes to scroll through your log and look for obvious problems: callsigns with unusual characters, exchanges that look wrong, or gaps in time that do not make sense. Most logging software includes a log-checking utility that flags potential issues.
The submission process varies by contest but follows a common pattern:
Always submit your log, even if you only made a few contacts. Checklogs (logs submitted by operators who are not competing for a score) help the contest committee verify other operators' contacts. You can explicitly mark your log as a checklog if you prefer.
Submission deadlines vary from five days to thirty days after the contest. Check the rules — late logs are usually not accepted.
After the results are published (often months later), many contests provide detailed log-checking reports showing which of your contacts were confirmed, which were not found in other logs (NIL — "not in log"), and which had errors. Studying these reports helps you identify weaknesses in your operating — for example, if you have a high NIL rate, you may be logging callsigns inaccurately.
Many contest logging programs maintain databases of your past contests. Over time, this data lets you track your progress, compare scores year over year, and set informed goals for future events. Some operators keep a separate general station log and import contest contacts into it after each event.