Super Check Partial and Call History Files in Contesting
Every contest log is scored twice: once by you as you operate, and once by the log checkers after the contest. The difference between those two scores comes mostly from errors: calls copied wrongly, exchanges mistyped, contacts that never made it into the other station’s log. Super check partial and call history files are the two tools contesters rely on most to close that gap. Used well, they catch errors in real time and speed up exchanges. Used carelessly, they turn a doubtful copy into a confident mistake.
This guide explains where super check partial came from, how it works in modern loggers such as N1MM Logger+, what call history files add, how to keep both current before a contest, and the operating habits that make them help rather than hurt. We focus on N1MM Logger+ as a worked example because it is widely used and well documented, but the ideas apply to most contest loggers.
What Super Check Partial Is
Super check partial (SCP) is a database of callsigns that have appeared in many contest logs, combined with a matching feature in your logging program. As you type a partial callsign, the logger shows every call in the database that contains that string. If you copied “K1” and “XX” but missed a character in the middle, SCP shows you the plausible candidates.
The idea is old by contest-software standards. The N1MM Logger+ documentation describes its Check window as the latest evolution of the super check partial idea originated by K1EA in the CT logging program. CT was one of the first widely used contest loggers, and the SCP concept has been built into almost every serious logger since.
The underlying database is distributed as a file, commonly called MASTER.SCP, compiled from logs of active contesters. The Super Check Partial website distributes the database files for use in loggers. Because active callsigns change over time, the file is refreshed regularly, and keeping a current copy matters.
How the N1MM Logger+ Check Window Works
N1MM Logger+ shows SCP results in its Check window. According to the program’s Check window documentation, it can compare what you type against up to four sources at once:
- Your current log: calls you have already worked in this contest.
- The master file: a Master.scp data file downloaded from the Tools menu of the Entry window.
- Telnet spots: calls received from DX cluster connections. A spot appears in this pane only if it has been spotted at least three times, or has a Q or V spot-quality tag on AR-Cluster version 6.
- A call history file: if one has been loaded for the contest.
The window begins checking from the third character you type, or when a call is transferred from the Bandmap. It uses colour coding to show likely corrections: characters highlighted in green indicate a partial match that could complete the call, while characters highlighted in red show what would have to change if you miscopied. A call already in your log but slightly different from what you typed is flagged, which is exactly the warning you want when you may have heard a station you worked earlier. A separate pane provides Reverse Call History Lookup, discussed below.
Each pane can be switched off from a right-click menu, so you can choose how much information you want in front of you while operating.
What Call History Files Add
SCP answers the question “does this callsign exist in contest logs?” A call history file goes further and answers “what did this station send last time?” It is a text file listing callsigns along with exchange information for a specific contest or family of contests: names for sprint-style events, states or provinces, zones, serial-free exchange elements, member numbers and so on.
When a call history file is loaded, the logger can pre-fill the exchange fields as soon as you enter a callsign. In a contest with a long or unusual exchange, that saves keystrokes and reduces typing errors. The Reverse Call History Lookup feature in N1MM Logger+ works in the other direction: from the exchange you copied, it suggests callsigns that sent that exchange before, which can help when you copied the exchange cleanly but not the call.
Call history files are contest-specific. The N1MM Logger+ website offers a download section for call history files, and many contest sponsors or clubs publish their own. Loading the wrong file, or an outdated one, can pre-fill exchanges that are no longer correct.
Comparing the Accuracy Tools
| Tool | What it checks | Where it comes from | Main strength | Main risk |
|---|---|---|---|---|
| Super check partial (Master.scp) | Whether a call has appeared in active contest logs | Database compiled from many logs, downloaded before the contest | Catches impossible or unusual calls instantly | Missing new calls; tempting you to “pick” a listed call |
| Call history file | Previous exchange data for a callsign | Contest-specific file from volunteers, clubs or sponsors | Pre-fills exchanges and flags differences | Outdated data, moved stations, changed names or locations |
| Log check (dupes and near-matches) | Calls already in your log | Your own contest log | Spots duplicates and near-duplicate busts | Relies on your earlier copy being right |
| Telnet spots | Calls spotted on clusters | DX cluster connections | Confirms calls heard by many others | Busted spots; category rules on assistance |
Remember that using spots, and in many rule sets any source that identifies calls for you, can move you into an assisted category. Our guide to ham radio contest categories explains the difference. Pre-loaded databases like SCP and call history are normally treated differently from live spotting, but check each contest’s rules rather than assuming.
Why Accuracy Matters to Your Score
Log checking is harsher than many newer contesters expect. Busted calls and “not in log” contacts are not simply removed; in many major contests they also cost a penalty. For example, the CQ World Wide DX Contest rules state that call sign errors (busts) and calls not in the other log (NIL) are removed and receive a penalty of two times the QSO point value for that contact, while incorrectly received exchanges and duplicates are removed without additional penalty. You can read the current version in the CQ WW rules.
That penalty structure changes the maths of guessing. Logging a doubtful call because it looked right in the SCP list can cost more than not logging it at all. The log-checking process behind these numbers, and the reports you receive afterwards, are covered in our article on Cabrillo logs and the UBN process. Reading your UBN report after each contest is one of the best ways to learn which kinds of errors you make.
Using Super Check Partial Wisely
The single most important rule is simple: SCP suggests, you copy. The database tells you which calls exist, not which call you just heard. Good habits include:
Treat a match as a question, not an answer
If SCP shows one plausible match, that is a reason to listen more carefully or ask for a repeat, not a reason to log the call. The station you are working may be a new call that is not yet in the database, or a similar call that happens to be listed.
Pay attention to “no match”
When a call you typed does not appear in the master file, that is useful information. It might be a busted copy, or it might be a new licensee, a special event call, a rookie or a station operating portable with a prefix or suffix. Ask for a repeat and confirm, and if the call is confirmed, log what you heard even though SCP disagrees.
Watch the near-duplicate warnings
A red-highlighted match against your own log often means you have either worked this station already or are about to log a bust of someone you worked earlier. Confirm before logging.
Do not let the screen replace your ears
In a busy pileup it is tempting to look at the Check window and pick. Build the habit of copying the full call first and then glancing at the check results as confirmation. Operators who get this backwards tend to see their error rate rise late in the contest when fatigue sets in; our article on rest and time management in long contests covers why errors climb as you tire.
Keeping Files Current Before a Contest
An outdated SCP or call history file is worse than none, because it gives false confidence. A simple pre-contest routine avoids that:
- Update the logger. Install the latest update of your logging program so contest modules and file formats match.
- Download the latest master file. In N1MM Logger+ this is done from the Tools menu of the Entry window. Other loggers have an equivalent download or import option.
- Load the right call history file. Choose one built for the specific contest, check its date and load it into the database you will use for that contest.
- Test before the start. Type a few known calls and confirm that the Check window and exchange pre-fill behave as expected.
- Note what is stored where. In N1MM Logger+, call history and some other data are stored in the database that was in use when you loaded them. If you create a new database, reload the files.
Common Pitfalls and Edge Cases
- New and rookie callsigns. Newly licensed operators and first-time contesters will not be in SCP. Do not treat them as suspicious; copy carefully and log what they send.
- Portable and special calls. Stations signing with a prefix, a /P or /M suffix, or a one-off special event call may not match. Confirm the full call including any additions.
- Changed exchanges. Call history may show a zone, state or name from a previous year. If the station sends something different, log what they sent, not what the file says.
- Similar calls. Some calls differ by one character and are both active. SCP will show both; only your copy can decide.
- Over-reliance in multi-op. In multi-operator stations, less experienced operators may trust pre-filled fields too much. Brief every operator on the “copy first, check second” habit.
Accurate logging also depends on sensible operating technique. Working stations efficiently while still getting full calls is covered in our guide to working a pileup.
SCP on CW, SSB and Digital Modes
The value of super check partial changes with the mode, and so do the risks.
CW
On CW, most busts are single-character errors: a dit missed or added turns one letter into another. That is exactly the kind of error SCP highlights well. The trap is that the “corrected” call suggested by the database may be a different, equally real station. When the colour coding shows a one-character difference, ask for the call again rather than accepting the suggestion. Pay particular attention to characters that are easily confused in Morse, and to the portable suffixes that are easily lost in the noise.
SSB
On phone, errors tend to come from phonetics, accents and poor signals rather than dropped elements. SCP helps you notice when what you think you heard does not exist, but it cannot tell you whether “five” or “nine” was said in a noisy exchange. Repeat the call back when in doubt; a quick confirmation costs seconds, while a bust costs points.
Digital modes
On RTTY and other decoded modes, the software prints what it decodes, including errors caused by noise and fading. SCP and call history help here as a sanity check on garbled decodes. On fully structured modes where callsigns are exchanged in a fixed format, the risk of a bust is lower but not zero, and a call that fails the check is still worth a second look.
Building Your Own Call History
Many contesters maintain their own call history from past logs, especially for regional contests and QSO parties with small, loyal fields. A personal file built from your own confirmed contacts reflects the stations you actually work, including local regulars who may be missing from larger files. If you do this, rebuild it from logs after each contest’s results are published, so that corrections from log checking are reflected, and remove entries that have not appeared for several years.
The Bottom Line
Super check partial and call history files are among the most valuable accuracy tools in contesting. SCP tells you which calls exist in contest logs, call history tells you what a station sent before, and modern loggers such as N1MM Logger+ combine them with your own log and cluster spots in one Check window. Keep the files current, load the right call history for each contest and test before the start. Above all, use them to confirm what you copied rather than to choose what to log. With busted calls and NILs carrying penalties in major contests, a careful operator with good tools will usually beat a faster one who lets the screen do the listening.
Frequently Asked Questions
What is super check partial?
Super check partial is a database of callsigns seen in contest logs, combined with a logger feature that shows matching calls as you type a partial callsign. It helps you spot and correct copying errors.
Where do I get the Master.scp file?
The database files are distributed through the Super Check Partial website, and N1MM Logger+ can download the master file directly from the Tools menu of the Entry window. Update it before each major contest.
What is the difference between SCP and a call history file?
SCP only checks whether a callsign exists in contest logs. A call history file also stores exchange information such as names, zones or locations for a specific contest, and can pre-fill exchange fields.
Does using super check partial make me an assisted entrant?
Pre-loaded databases are generally treated differently from live cluster spots, but rules vary by contest. Read the rules of each event, especially how it defines QSO finding assistance.
Should I log a call that is not in the SCP database?
Yes, if you have confirmed it. New licensees, rookies, portable operators and special calls are often missing. Ask for a repeat, copy carefully and log what the station actually sent.
How much do busted calls cost?
It depends on the contest. In CQ WW, busted calls and not-in-log contacts are removed and penalised at two times the QSO point value of that contact, so careful copying pays.