Cookies are not used on this site but 'local storage' is. Local storage is essential for so many features the site won't work without it.
There are no third party trackers, no advertising, no Facebook logons etc.
Local storage is also known as web storage or DOM storage web storage
If preferences and callsigns are not saved, turn on local storage for your specific browser, eg. how do I turn on web storage in Firefox?

Its used for saving Rx & Tx drop down menus, user prefs, saved search params, saved tables, saved the stats on the stats page, advanced search, auto search, notifications and version updating.

Security and privacy: try Brave browser, I love it. Good security, terrific speed, good compatibility and layout. It uses the Google Chrome public domain engine but has none of Google's tracking, Firefox is clunky by comparison. Check it out and note who created it and why.

Brave on Mac, Linux and Windows is my primary development environment.
Safari: runs fine but can hang on to cached data for over a day so that recent code updates sometimes don't appear.
Firefox: used to break some features on all platforms but the latest versions seem to be working fine.
Microsoft Edge: is being rebuilt by Microsoft based on Chromium open source code but still delivers poor appearance and compatibility.
The others: there is no browser detection so it will try to run in anything but will certainly fail in older browsers. MS Internet Explorer is not supported.
Mobile devices: tests OK in Brave/Chrome/Safari/Firefox on iPhone 11 and iPad Air 2, your mileage will vary. Some features are not available on touch screens.

Most bugs are able to be fixed quickly but sometimes its browser age or quirks.
- adding new features means more bugs so your patience and assistance in reporting them is appreciated.
- blank map page: now rare, sometimes your browser has cached old files. Try Google [ how to clear my browser cache ]
Bug reports to phil at perite dot com are welcome as are suggestions for features and improvements.

Search view:
- callsign drop down menus: customise the order by dragging callsigns up or down.
- click the pink 'advanced search' at the bottom right of the tab bar to open the Advanced search panel.
- as well as the advanced menu selections you can edit the advanced query text directly; if you know a bit of SQL you can generate your own additional WHERE clauses using OR and other functionality.
- Alt click the Search button to generate a link to this site with your search parameters. Copy and paste it into an email or a forum and click on it to launch this app and automatically carry out your search.

Table view:
- click a date to toggle it between local and UTC.
- click a callsign to show the country an amateur callsign is registered in.
- click a column heading to sort the column up and down.

Map Legend:
- click the [distance] button to toggle through three other Legends featuring 'SpotQ', 'QRP (Watts)' and 'Band Count'.
- click any callsign to zoom to that station for more station information.
- in the 'Band Count' legend, click a count number to show only that band, click a dash - to restore all paths.
- click the ▽ down box to hide Google's map controls which is handy on phone screens.

Paths on the Map: click any Path to view its Spot data. Click a dashed Long Path to see distance and dB free space path loss at the path frequency.

Map Markers:
- click for station information, it's pretty obvious but some people miss it.
- right click a marker to open the Map Extras window and draw it's 4 and 6 char locator squares or use the Great Circle Ruler.

The Map:
- right click on the map to open the Map Extras window to draw a Great Circle ruler. See the Great Circle Ruler entry below.
• search for spots between any two user defined points on the map. See the Great Circle Ruler entry below.
• continuous 6 figure Maidenhead locators are displayed to the left of the Night button as you move the mouse around the Map.
• toggling between 'callsigns' and 'dots' redraws the map allowing you to switch between balloon tracks and normal view (in prefs) without a fresh search.

Chart: the dots are band colour coded. Mouse over or touch them for their spot details.

Timeout problems and search limitations on the WSPRnet.org site inspired the creation of a clone database by the guys at WsprDaemon.org
Simple searches should be very fast over a reasonable internet connection.
Long time period and complex searches can be slower because the WSPR Daemon db provides access to three weeks of data.

New wild card characters:
_ represents a single character or number
% matches zero or more characters or numbers

The WSPR Daemon database is updated continuously in real time from WSPRnet.org and is some 30 seconds or so behind.
There is a neat diagram courtesty of Arne of the data flow from WSPRnet to WSPR Daemon db diagram

The unique checkbox applies only to the values you place in the Tx and Rx search boxes.
The choices of time, band, mode etc still limit the spots returned but the test for 'equality' applies only to the callsigns.
Consider the stations Bill, Annie and 'anyone':

1. unique on Rx='Bill' and Tx='Bill'
This search is really useful if Bill's station receives AND transmits.
- it returns one single spot from every station heard by Bill AND one spot from every station who Bill heard.
- those spots are the first spots found in the database and are not sorted for best SNR or distance.
- if 'all bands' is selected you still get only the first spot found regardless of whether there were other spots on other bands.
The WSPRnet.org unique search behaves in the same way. Note: the new http://wspr.live beta does include one spot for each band found.

2. unique on Rx='Bill' and Tx='Annie'
- returns the first spot found in the database between Bill and Annie.
- if 'all bands' is selected you still only get the first spot found regardless of whether there were other spots on other bands between Bill and Annie.
The WSPRnet.org unique search behaves in the same way. Note: the new http://wspr.live beta does include one spot for each band found.

3. unique on Rx='Annie' and Tx='anyone'
- returns one single spot from every station who Annie heard.
- again, those spots are the first spots found in the database regardless of whether there were other spots on other bands.
The WSPRnet.org unique search behaves in the same way. Note: the new http://wspr.rocks site does include one spot for each band found.

4. unique on Rx='anyone' and Tx='Annie'
- similar to (3) above

5. unique on Rx='anyone' and Tx='anyone'
- returns the first spot found for all stations
- only one spot is returned for each pair of stations regardless of whether there were other spots between them on other bands.
The WSPRnet.org unique search behaves in the same way. Note: the new http://wspr.rocks site does include one spot for each band found.

Unique is handy for reducing the number of spots returned so you can stay under the spot count limit when searching over long time periods.
Its good for tracking balloons, only one spot is needed to show each location on the track thus enabling tracking over longer periods of time.

Advanced search is accessed via the 'advanced search' link at the left under the tab bar or via a button in 'prefs'

- advanced search applies extra criteria in addition to your choices in the normal search.
- you can edit the advanced query text field directly; if you know some SQL you can generate additional WHERE clauses using OR and other functionality.

Auto-search gets you the fastest possible map updates!
Because WSJT uploads user spots every even minute the uneven minute auto search captures the very latest data. Do not keep clicking the search button!
By default, Auto-search commences searching on the first uneven† numbered minute, two minutes after you click the auto-search check box.

You can change the two minute default period (via ☰ prefs) to any value from 2 minutes to 60 minutes.
A 3 to 8 second random interval is added to the ☰ prefs period to avoid collisions with other users.
If a search times out the failure is ignored and does not alter the next search time.

Note: if your computer goes to sleep or browser becomes inactive in a background tab the timer may stop or run very slowly.
Open your browser Console to view a running log of auto-search activity.

To create a search URL (1)set the search values to whatever you want, then (2)hold down the alt/option key and click the [Search WSPRD] button.
- click on the middle of the grey url text that appears to select it and copy and paste it into your email or document.
- it might look something like this: http://wsprd.vk7jj.com/?action=fetch&rxCall=vk7jj&txCall=&count=3000&band=40&hours=24&unique=true
- advanced search parameters are not supported, sorry.

If you change the word "fetch" to "auto" the link will initiate the search and also turn on the auto-search facility.

Conduct a search and then select 'Store table...' from the Table options menu.
Select 'Restore table...' to load a previously stored table.
The data is saved within your browser in an area called "local storage" in a similar way to cookies.
The data will be lost if you empty your browser cache or if this app changes to another domain.

Note: This feature is designed for mobile phones and tablets that can't handle saved files. On desktops you should use the 'Export spots to disk...' option for more secure storage.

Enter the callsigns and set the band and other menu values you wish to save and click [Save search] in the ☰ prefs.
Ticking the [restore] checkbox automatically restores your saved search values every time you refresh or open the web page.
Ticking and unticking the [restore] checkbox does not delete the saved values, it just triggers the restoration.
Note: Advanced search is now saved along with normal search. Advanced criteria are not visible unless that panel is open your so search results may be unexpected.

SpotQ is the relative Quality of a spot, ie. how "good" it is.
The best spot is the spot that was received over the GREATEST distance at the LOWEST power and the BEST signal to noise ratio.

The formula for calculating SpotQ was changed on 2nd Feb 2020
• The original formula worked well but had one downside in that normalisation made it relative to a given set of search results rather than being an absolute value.
• The new formula is simple and generates absolute values so SpotQ can now be compared between multiple stations and multiple searches as per the Stats feature.

The old formula was (Kilometres ÷ Watts x SNR) where SNR = WSPR SNR in dB normalised to a decimal value between 1 and 2.
The new formula is (Kilometres ÷ Watts x SNR) but SNR now = (WSPR SNR in dB +36)/36

The reason SNR needs manipulation is to ensure it is always positive, has sufficient resolution to separate stations only a dB or a kilometre apart and is short enough to fit in a Table column.
SpotQ is very useful for comparing and improving your own antennas and receiver systems as well as comparing the performance of different receiving stations.

Click the [Stats] tab to display the statistics page.
Add a callsign in the 'stats call' field (in the top dark grey page header) and click its 'collect stats' checkbox.
- regardless of whether you specifically search for that callsign or not if it's is found in any search results its stats are updated automatically.
- you can have up to 6 stats callsigns in total but only two can collect stats simultaneously.

Stats are great for comparing the performance of two antennas or radios or users.
- deleting a Stats callsign permanently deletes any stats collected for it.

Database search
- the upper part of the stats page allows you to search the entire db for specific information like average distance, SNR etc.
- enter a callsign in the 'db call' field to get results for just that call, leave it blank to get the max, min, averages etc for 'everybody'.

Click the [highlight duplicates] button in the table menu.
The first duplicate for every set of duplicates will be highlighted. There may be multiple sets.
Click anywhere on a coloured line to see the frequency and SNR differences between each spot in that duplicate set.
To see the actual list of duplicate spots in any set of duplicates, open your browser console.

Duplicates are caused by:
• multiple receivers operating under one callsign.
• mains hum: look for frequency differences that are multiples of 50 or 60 Hz, they can be caused by the sending or receiving station.
• spurious / distorted transmitter output: look for multiple signals of a similar strength that are not harmonically related but are within a few Hz of the main signal frequency.
• "normal" transmitter harmonics when within range of a strong signal: usually you see the main signal at something like +10dB with symmetrical harmonics down around -20dB

1. Search on one band only for 200 or fewer spots.
2. Click the Search button and wait until the spot table appears.
3. Choose [WSPR audio passband] from the Charts menu to show spot distribution within the 200Hz wide WSPR passband.
4. Mouse over the chart to see the number of spots and their frequency.
Search for a tx station that uses a GPS disciplined oscillator and you can check your receiver frequency accuracy within 1Hz.

There is only one single path between any two stations so there can only be one path displayed regardless of the number of transmissions between them.
- the path that is drawn is for the first spot encountered in the database that meets your search query.
- that would normally be the most recent spot although different advanced search options could change that.
There may well be other spots in the table on the same path on the same band or on different bands or with differing times.

The following charts only make sense when searching for specific spot data:
Frequency vs time of day: search for a particular callsign or wildcard.
SNR vs Time: search for a particular reporter or reporter/transmitting station combination.
Rx Azimuth: search for a particular reporter.
Tx Azimuth: search for a particular transmitting station.
Compass.
Mousing over or clicking a chart's coloured dots shows each spot's information

When in the Map view click the [night] button to show or hide the night overlay.
The overlay defaults to "now" and shows night + civil, nautical & astronomical twilight at the current date/time.
Every time you click the night button its status is automatically remembered and restored.

The night overlay position can be moved to the time of any particular spot:
- click on any spot marker on the map to open that marker info window.
- click the link [show night as at this spot time] to position the overlay.

The overlay position defaults to "now" for every new search or when loading previously saved spots or whenever the [night] button is toggled.
Limitations: 1) some early browsers cannot handle the date calculations. 2) it does not work for tables saved in early versions.

The 'watts' slider in Map view shows and hides spot paths based on the Tx power of the spot.
Search for your chosen set of spots with the 'unique' checkbox ticked.
Move the slider. It starts showing all spots and then hides them incrementally down to 1 milliwatt.
The two sliders can't be used simultaneously because they try to show and hide the same spots based on different criteria.

The 'hours' slider control in Map view shows and hides spot paths based on the hour-of-day of the spot.
Search for 24 hours or more for your chosen set of spots with the 'unique' checkbox ticked:
- the [night] button is automatically activated when you move the slider. Turn it on and off yourself to suit.
Move the slider. It starts at 00 hours and increments hourly to 24 hours.
When the slider is first moved the night overlay will jump from 'now' to 00 hours, after that it will move incrementally.
Note: the slider shows and hides only the paths already displayed on the map, it does not create new paths for any additional spots on the same frequency; see The Map entry above.
The two sliders can't be used simultaneously as they try to show and hide the same spots based on different criteria.

Right click anywhere on the map to open the map Extras window and then click to display the ruler.
Hint: you can zoom and pan in before opening the ruler as it adapts its size to the view.
Drag the markers to any two points on the map:
- click the pale blue ruler path to display an info-box relevant to that location.
- right clicking a marker is a short cut for closing the ruler.
- the ruler can toggle between a geodesic or straight path which affects the appearance but not the measurements.
- the ruler info window stays open and does not update when the ruler is moved. This allows multiple windows to stay open for comparing different paths.

The ruler is accurate to a meter and can measure the length of wire antennas in satellite view, just ignore the 'km' label. I built my 160m loops with an early version of it.
If the path length becomes greater than the diameter of the earth it flips to the other side of the planet.

Show propagation along the path.
- clicking [fetch A⇢B or B⇢A propagation] searches the database for spots between the A and B marker locations.
- you can select the hours, mode and band yourself as per a normal search but unique is always set to ON.
- the Band Count legend automatically displays to show the band count.
- in the Band Count legend, where there are spots on a band, click on a band count number to display only that band. Click a - to show all bands again.

The area covered by an A or B marker is the Maidenhead square described by the first two digits of their locators.
- if you zoom in closer the area is reduced to the first three digits of their locators.

WSPRnet.org's map page draws only short paths regardless of whether a spot is long or short path.
The short path is known as the great circle path and is the shortest path between two points on the surface of a sphere.

Spot data can't tell if the path should be short or long, that's up to you to figure out based on your experience, your antenna, time of day, propagation etc.

You can display the long path for any spot on the map:
• click on any short path then click the [toggle this path as long] link in the pop-up dialog.
• click on the long path dashed line to show the free space path loss and distance for both paths.

Showing the long path shows you what the path looks like, the comparative path losses, what part of the day/night cycle is involved and what the distance and beam heading is. Displaying those things hopefully helps you figure it out.

The "hours" slider available in Map view is also a good way to identify long paths:
- make sure the night overlay is visible and drag the slider
- any 40m paths that are longer than 3,500km with the path mostly in daylight are almost certain to be long.

Identifying long path spots on the map has been a personal holy grail. This is a 40m only feature.

What characterises a long path on 40m? (ref)
Any 40m path longer than 7,000km where the centre of the path is close to solar noon at the time of the spot is almost certainly long path.

Search for 24 hours of unique spots for a 40m station either Rx or Tx with known good DX capabilities then go to Map view.
- click any path and then click '[highlight any 40m long paths]' Any long paths will turn black in colour and an alert will indicate how many there are.

If there are any long paths found, move the hours slider with night turned on and watch the relationship between solar noon and all the 40m paths.
- if you can't find any stations with 40m long paths try 24 hour 40m unique RX searches for VK7JJ or DK6UG or EA8BFK, they are usually regulars.

Each marker is drawn on the map in the centre of the locator sent in your transmission as specified in WSJT-X or other software.

right click the map anywhere to open the Map Extras window to draw 4 or 6 char locator squares at the map click location.
The dimensions of the most recently drawn locator square are displayed in the status -> line.

Moving the mouse around the map gives a continuous readout of the 6 figure locator beneath the mouse pointer.

A six figure locator square is about 9.2k wide and 4.6k high at the equator.
Because locator squares are bounded by longitudes they narrow as you move towards the poles, DP0GVN's locator IB59uh is 3k wide
A four figure locator square is 2° wide and 1° high, equal in size to 24 six figure locator squares. A 4 figure locator could position you up to 100k away from your real QTH.

Check out the QRPLabs balloon page to find a callsign to search for.
Eg. Flight U4B-6 used the callsign VA3AUL. Search for that Tx callsign for two weeks with the unique box checked.
- open the ☰ prefs panel and click the 'balloon' radio button and then click the Map tab. Failure to do this will draw the balloon path as if it was normal spots.

Balloon transmission time offset
- VE3KCL balloons all use that callsign but transmit in time slots of 0, 2, 4, 6 or 8 minutes after each UTC hour.
- you can set the balloon time slot in the advanced search panel.

Balloon tracks show abrupt direction changes because each TX location is the centre of a 4 figure roughly 50km wide grid square.
Click a track segment to display the length of that section of the path.

QRPLab balloons typically transmit a normal WSPR packet every minute ending in 6. That can change, check each balloon flight details.
- WSPR telemetry packets are typically sent on minutes ending in 8 but with coded callsigns, eg. beginning with 0C.
- Altitude, temperature, speed, battery voltage etc are encoded in the rest of the callsign and other WSPR fields.

ZL1RS was another balloon callsign to search for. ZL1RS Bob's balloons have performed excellently and circumnavigated the world.
Don't forget to switch the ☰ prefs panel back to WSPR for normal use.
Hint: toggling between 'callsigns' and 'dots' redraws the map; you can switch between balloon tracks and normal view (in prefs) without a fresh search.

Conduct your search as normal.
- select 'Export spots to Google Earth...' from the Table options menu and save the file on your computer desktop.
- presuming you have a copy of the Google Earth application on your computer, double-click the file to open it in Google Earth.
- Google Earth has limited ability to display data but clicking on a marker gives basic spot information.
- multiple spots show up as a bunch of satellites around a marker, improving how that works is on the non urgent to-do list.

Search for a balloon as per the Display a balloon paragraph above.
When the Table is filled with Tx spots from the balloon:
- select 'Export balloons to Google Earth...' from the Table options menu and save the file on your computer desktop.
- your exported file will now contain the balloon's track in KML format, double click it to launch Google Earth.
- markers are centered in each WSPR locator square.
- the above procedure should work with any moving transmitter such as a boat, car or aircraft.

Select 'Export spots as .tsv to disk' from the Table options menu and save the file on your computer desktop.
.tsv is tab-separated-values for copy and paste or importing into any spreadsheet.
The .json file is in JSON format to be saved or archived for reloading later.
Import previously saved .json files by selecting 'Import spots from disk...' from the Table options menu.

Only plain text .txt files containing Comma Separated Values (CSV) can be imported. Zipped files are not supported, unzip them first.
File size is hard limited to 3,500 kilobytes because that's the effective limit of Google Maps and Charts.

You can directly import WSPRnet CSV files from their download page provided you remove enough spots to reduce the file size as above.
Editing them not a problem as long as you guarantee to preserve the 15 item comma delimited values as per the WSPRnet specification.

Note: The files are ordinary text files containing comma separated values and MUST have a .txt extension (not .csv) or they will not be imported.

Its not a true ping because Javascript can't ping, its a request for the favicon icon on their site.
The ping time gives an indication of how fast the server is ... or how bad your internet service may be.