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VHF Logger

User guide and setup — VHF/UHF contest logger with aircraft scatter

Logger: zlog.html  ·  This help file: zlog-help.html

1. First-time setup

When you open the logger for the first time, Settings opens automatically. Fill in these fields:

Station identification

Address (used in EDI submission)

Station equipment (used in EDI submission)

2. Logging a QSO

Form mode — step-by-step example

The following example logs a QSO between OZ7Z (your station, JO44VW) and G3YDY (JO01FQ) at 17:15 UTC on 144 MHz:

1. Dato — leave empty for today, or type 260101 for a specific date. Press Enter.
2. Tid — leave empty for current UTC, or type 1715. Press Enter.
3. Call — type G3YDY and press Enter. If G3YDY is in your locator database, the Loc field fills automatically.
4. RST S — your report to G3YDY. Type 59 (or leave 59 as default) and press Enter.
5. RST R — G3YDY's report to you. Type 57 and press Enter.
6. Nr S / Nr R — serial numbers, if enabled. Otherwise skipped.
7. Loc — type JO01FQ and press Enter. The distance (720 km) is calculated and the QSO is saved.

One-liner mode

Enable under Entry mode → One-liner in Settings. Type everything on one line and press Enter. Tokens are order-independent — the logger recognises each by its format.

Important convention: the RST you send (your report to the other station) is marked with an apostrophe ' after it. The RST you receive is written without an apostrophe.

Full format: CALL [HH:MM] [SND-RST'] [RCV-RST] [NR] LOCATOR
Locator and callsign are the only required fields — everything else is optional.

Entering a custom time and date (one-liner)

To log a QSO with a time other than the current UTC time, type it in HH:MM format anywhere in the one-liner line — e.g. 17:32 G3YDY 57 JO01FQ. The hint line confirms it is recognised: Tid: 17:32.

To log a QSO with a different date, fill in the small Dato YYMMDD field that appears below the input box (e.g. 260101 for 1 January 2026). Leave it empty to use today's date. The date field is not cleared between QSOs so you can log several QSOs with the same back-dated date without re-typing it. Press F3 to clear the date field together with the input.

Entering a custom time and date (form mode)

Form mode has a Dato YYMMDD field and a Tid UTC field at the start of the form. Both default to the current date and time if left blank. They are cleared automatically after each QSO is saved.

Locator autocomplete in one-liner

When you press Space after a callsign the logger looks it up in the locator database automatically:

• One match — the locator is inserted in the field immediately. Continue typing RST.
• Multiple matches — a picker appears above the input field. Navigate with ↑ / ↓ and confirm with Enter, or click with the mouse. Press Esc to dismiss.
• No match — space is inserted normally; type the locator yourself.

Wildcard callsign lookup

Use ? as a wildcard for a single unknown character in a callsign. Press Space after the partial callsign to search the locator database:

A picker appears with all matches from the database. Select the correct station — the wildcard token in the input is replaced with the actual callsign and the locator is inserted automatically.

Prefix search also works without wildcards: type OZ7 and press Space to see all database entries beginning with OZ7.

Queuing the next QSO — /n

While logging a QSO you can note one or more upcoming stations using /n CALL anywhere in the line:

The hint line shows the queue as → G4SWX → SM5EPO while you type. After logging:

1. The first queued callsign is pre-filled (with locator from DB if available).
2. The remaining /n entries stay in the input so they are passed on when that QSO is logged.
3. When the last queued QSO is logged the input clears normally.

3. Score

The score is shown continuously in the bar below the top menu:

• KM pts — sum of distances for valid QSOs
• WWL × 500 — 500 points per unique Maidenhead square (4 characters)
• Total = KM pts × band multiplier + WWL bonus

Worked example

You are OZ7Z (JO44VW) on 144 MHz and have logged three QSOs:

Score calculation:

KM pts  = 720 + 630 + 700 = 2050
WWL     = 3 unique squares × 500 = 1500
Total   = (2050 + 1500) × 1 = 3550

The band multiplier is ×1 for 144 MHz. Microwave bands get a higher multiplier:

4. EDI export

Click ↓ EDI to download your contest log in REG1TEST format (Tucnak-compatible). The file can be uploaded directly to vushf.dk.

Filename: OZ7Z_144MHz_260506.edi

Example of what the exported file looks like:

[REG1TEST;1]
TName=NAC 144 MHz
TDate=260506;260506
PCall=OZ7Z
PWWLo=JO44VW
PBand=144 MHz
PSect=3L
RName=Jens Hansen
REmail=jens@example.dk
[QSORecords;3]
260506;1715;G3YDY;1;59;001;57;001;JO01FQ;720
260506;1732;G4SWX;1;59;002;59;003;JO02RF;630
260506;1801;SM5EPO;1;59;003;59;007;JO89WK;700

Each QSO line: date ; time ; call ; mode ; RST-sent ; nr-sent ; RST-rcvd ; nr-rcvd ; locator ; distance-km

5. Locator database

Import a text file with known stations for callsign autocomplete. One station per line:

G3YDY;JO01FQ
G4SWX;JO02RF
SM5EPO;JO89WK
OZ7Z;JO44VW;Allan

Supported formats:

• CALL;LOCATOR
• CALL;LOCATOR;NAME
• DATE;CALL;LOCATOR;NAME (Tucnak EDI style)
• Whitespace-separated: CALL LOCATOR …

A callsign may appear more than once with different locators (e.g. a portable station at different QTH). If there are two or more locators for the same call, a picker appears when you press Space in the one-liner or leave the Callsign field in form mode.

Click 📂 Load locator file in Settings. The database is stored in the browser and merged with any new file you load.

6. Aircraft scatter

Aircraft scatter allows VHF/UHF QSOs over long distances via reflection from aircraft. Flight data is fetched via vushf.dk as a proxy — it tries airscatter.dk first and automatically falls back to OpenSky Network if airscatter.dk is unavailable. The active source is shown in the info bar below the map: 42 aircraft · airscatter.dk or 42 aircraft · OpenSky.

Adding stations to the Watchlist

Open ⚙ Settings and scroll down to the Watchlist section. It contains 20 rows. Each row has two fields:

• Kald — the station's callsign
• Lok — its 4- or 6-character Maidenhead locator

Type directly into the fields; they save automatically as you type. Leave unused rows blank. Close Settings when done — the Watchlist tab updates immediately.

Example of a filled-in Watchlist:

Getting started with scatter

1. Click ✈ Planes in the top bar — aircraft within the search radius are now fetched every 10 seconds.
2. Open the Watchlist tab in the left panel.
3. Tick the checkboxes next to the stations you want to check scatter against. Use the header checkbox to select all at once.
4. The logger automatically shows which aircraft are in scatter position and when the next one arrives.

What does the watchlist show?

Scatter parameters

The scatter corridor angle and minimum aircraft distance are set automatically based on the selected band. You can adjust them manually in Settings:

Map overlays

• Zone — shows the yellow scatter corridor polygon on the map
• Lines — shows a green line between your station and the remote station during active scatter

7. ON4KST chat

The logger has a built-in client for the ON4KST VHF chat network. Use it to arrange skeds with other operators during a contest.

Connecting

1. Click the KST tab in the top-left panel.
2. Enter your callsign, password and the channel you want to join (e.g. 144 for the 144 MHz room).
3. Click Connect — incoming messages appear in the chat window.
4. Type a message in the input box at the bottom and press Enter to send.
5. Click Disconnect to log out.

Right-click — scatter sked from Watchlist

When a station in the Watchlist tab is also online on KST it shows a ·KST badge next to its callsign. Right-click the callsign to open a context menu with a pre-filled scatter sked message. Example:

G3YDY pls sked on 144.300 AP in 8 min

The frequency is taken from your active band and the time is the current scatter ETA. Edit the message if needed and press Enter to send it.

Online tab — all logged-in users

The Online tab (tab 4) shows all stations currently logged into the KST channel. Click Fetch active users to refresh the list. The list is filtered by distance — only stations within the configured maximum (default 1000 km) are shown.

Right-click any callsign in the Online list to send a CQ message pre-filled as /cq G3YDY.

8. Layout

• Drag the vertical divider between the log panel and the map to adjust the width.
• Drag the horizontal divider above the watchlist to adjust the map height.
• Switch between Log list, Watchlist, KST and Online using the tabs in the top-left.
• Select a theme from the dropdown in the top-right:

  Theme	Description
  Dark	Very dark background (near-black). Map tiles are heavily dimmed. Best for operating in complete darkness.
  Dim	Softer dark background with slightly more contrast. Map tiles are a little brighter than Dark. Comfortable for extended use in low light.
  Warm	Dark background with an amber tint. Map tiles get a sepia filter. Easy on the eyes during evening sessions.
  Light	White background, standard bright mode. Map tiles are shown at full brightness. Best in daylight.

9. Keyboard shortcuts

10. Data and backup

The log is saved automatically in the browser's localStorage after every QSO — it survives browser restarts. Data is not deleted when the page is refreshed.

To move your log to another computer: use the browser DevTools (F12 → Application → Local Storage) and copy the keys zlog_log and zlog_settings.