Nonemm/docs/n1mm-interop.md

Opening a Nonemm log in N1MM

Checked on 2026-08-27 against N1MM Logger+ 1.0.11031 by writing a log here, copying it to a Windows machine and opening it there. N1MM read the contest, its categories and the contacts.

Three things had to be right, and none of them is obvious from the schema.

The Contest table needs a row for the contest

ContestInstance says which contest a log is; the Contest table says what that contest is. N1MM reads it in Contest.FromRow when it opens a log and throws InvalidOperationException: No current row if the row is missing, which reaches the operator as "A runtime error occurred".

So the definition row is written whenever a contest is opened, not only when it is created — a log made before this was understood gets its row the next time it is opened. ContestDefinitions.For builds the row from the contest's own rules: the display and Cabrillo names, the mode, the dupe type and the multiplier names.

The overlay category cannot be empty

An empty ContestInstance.OverlayCategory is answered with "Invalid Overlay Category:" and the log will not open. An entry with no overlay says N/A.

N1MM's list is not the Cabrillo specification's list. N1MM offers:

N/A, ROOKIE, BAND-LIMITED, TB-WIRES, OVER-50, HQ, NOVICE-TECH, EXPERT

so that is what the contest dialog offers.

The sent exchange omits the report

N1MM's contest dialog says "Omit RST: CQWW: 05". SentExchange for CQ WW is 14, not 599 14; for a serial number contest it is 001. The report is fixed for the whole contest and the entry window fills it in per contact.

Getting the schema in the first place

N1MM ships no template database. ham.s3db is built at run time by applying SQL migration files that N1MM writes out from string resources inside N1MMLogger.net.exe. To read them: decompile the executable, parse N1MMLogger.Net.Resources.resx, and take the untyped <data> entries named DXLogDDL_0001_initial_schema_and_data through DXLogDDL_0004_updates. The QSO table is DXLOG and the current PRAGMA user_version is 4.

src/Nonemm.Storage/Schema.sql is that schema, flattened to the state version 4 leaves behind.

One thing to avoid

Do not replace the database file under a running N1MM. It does not notice and throws on the next read.

A contact belongs to a ContestNR, not to the table key

ContestInstance has two numbers: ContestID, the table's primary key, and ContestNR. DXLOG.ContestNR refers to the second one. N1MM's ContestInstance.SQLWhereString reads:

" ContestNR = " + this.ContestNR + " "

In a fresh log the two numbers match, so keying on either works. In a log N1MM has been using for a while they drift apart. In one real log of 56284 contacts, joining DXLOG.ContestNR to ContestInstance.ContestID disagreed with the contact's own ContestName 52029 times; joining it to ContestInstance.ContestNR disagreed 109 times.

So ContestInstance.ContestNumber here is ContestNR, and ContestID is allocated separately when a contest is created.

N1MM names a contest per mode

CQ WW is CQWWCW, CQWWSSB or CQWWRTTY, never plain CQWW. The full list lives in the Contest table of any N1MM database. Nonemm writes the same names, and N1mmContestNames turns one back into a contest and a mode when a log is opened. The name carries the mode, so it beats whatever ModeCategory says.

Older N1MM versions wrote the CW running of CQ WW as plain CQWW. That name is still in the registry, so those logs open.

Which column an exchange lands in

N1MM keeps the received exchange of ARRL DX, IARU and WAE in Sect, not in Exchange1, whatever the entry window calls the box. A contest that reads the wrong column scores every contact as if the operator had typed nothing, so the rule reads the column N1MM writes and the entry window points its box at the same place.

N1MM also writes a single space into a text column it has nothing for, so Continent comes back as " " rather than empty. Reading it as a value rather than as empty makes every contact look like another continent. The store trims what it reads.

Scoring checked against a real log

om5m.s3db in the repo root is a station's own N1MM log: 78 contest instances from 2019 to 2026, 57,000 contacts, 28 contest names. Replaying it is how the scoring rules are checked — every contact is scored again from our rules and compared with the points and multiplier flags N1MM wrote.

29 of the 37 instances whose contest we have rules for agree on every contact and on the totals. What the check found and fixed:

What	Was
ARRL DX and IARU read the wrong column	no multipliers at all, and IARU scored every contact 1 point
a stored " " was read as a value	181 contacts in one log scored as another continent
the Canadian area lists	ARRL DX and CQ WW RTTY count the 14 areas N1MM calls 48SDC14P, Newfoundland apart from Labrador, and the postal codes map onto them
a maritime mobile scored nothing	it is scored from the call it signs, which is the country N1MM logs for it
a call the country file cannot place brought no multiplier	it counts, with an empty value, and all such calls share the one multiplier per band
a contact in a mode the contest does not run	scored as if it were in the contest; N1MM scores it zero and keeps its multiplier

What still differs, and why. None of it is a rule:

• The country file of the day. A 2019 log holds calls that today's wl_cty.dat places elsewhere — TO7O was Mayotte then and is France now, China was not split by call area yet — and the multiplier moves to another contact with it. This is nearly all of the difference in the 2019 CQ WW SSB log and all of it in the 2021 ones.
• Stale cached points. N1MM caches points in the row and does not always work them out again after a callsign is corrected, so a handful of rows hold a number that its own rules do not produce. Two IARU rows and about six CQ WW rows across 57,000 contacts.
• A one-contact log whose contact also sits in another instance of the same contest.

What N1MM does that the published rules do not say

Three of the fixes above follow N1MM rather than the rule as published, because a log has to score the same in both programs:

• ARRL DX counts NF and LB as two multipliers. They are one province.
• A maritime mobile counts for the country of the call it signs. CQ WW says it counts for the zone alone.
• A callsign that places nowhere counts as a multiplier with an empty value.