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The amateur radio community maintains an enormous collection of web-based tools, databases, and resources that require no software installation. Whether you need to look up a callsign, check propagation conditions, find a repeater, or calculate the dimensions of an antenna, there is almost certainly a website for it. This page catalogues the most useful and widely used online tools, organised by category.
Callsign lookup is one of the most common tasks in amateur radio — you hear a station on the air and want to know who and where they are. Several online databases provide this information.
QRZ.com is the most widely used callsign database worldwide. It provides name, address, grid square, licence class, and often a biography and station photographs uploaded by the operator. QRZ also offers an online logbook, an XML lookup API used by many logging programs, and active forums. A free account provides basic lookups; a paid subscription unlocks additional features and removes advertisements.
HamQTH is a free alternative callsign database maintained by OK2CQR. It provides similar lookup functionality and an XML API. Many logging programs support HamQTH as a lookup source, and it is a good option for operators who prefer a free service.
HamCall (Buckmaster) maintains a comprehensive callsign database with historical records and international coverage. It is available as both an online service and a downloadable database.
National licensing databases — Many countries provide official online databases of licensed amateurs. The FCC's Universal Licensing System (ULS) covers the United States, Ofcom provides UK licence data, and other national regulators maintain similar systems. These are the authoritative source for licence information in each country.
Understanding current and predicted propagation conditions is essential for making contacts, especially on HF. Several online tools help with this.
PSK Reporter (pskreporter.info) is one of the most powerful real-time propagation tools available. It collects automated reception reports from stations running WSJT-X, fldigi, and other digital mode software, and displays them on a global map. You can see which stations are hearing your signal and where signals from a given region are being received. PSK Reporter works for any digital mode that reports callsigns, including FT8, FT4, WSPR, and PSK31.
DX Maps (dxmaps.com) provides real-time maps of DX cluster spots, showing where contacts are being made on each band. This is particularly useful for seeing band openings in progress and for VHF/UHF propagation events like sporadic E.
WSPR Rocks and the WSPRnet database display WSPR (Weak Signal Propagation Reporter) beacon reports. WSPR is a mode designed specifically for propagation research — low-power beacon transmissions are decoded and reported automatically, creating a detailed picture of HF propagation paths worldwide.
Solar data dashboards — Several websites display current solar indices that affect HF propagation: solar flux index (SFI), sunspot number (SSN), A-index, K-index, and geomagnetic field status. NOAA's Space Weather Prediction Center is the primary data source; amateur radio sites like hamqsl.com and solarham.com present the data in ham-friendly formats.
VOACAP Online (voacap.com) is a web interface to the Voice of America Coverage Analysis Program, one of the standard HF propagation prediction models. You enter your station location, the target station's location (or a target area), your power and antenna, and the time period. VOACAP predicts the probability of a usable signal on each HF band throughout the day. It is invaluable for planning DX attempts and understanding seasonal propagation patterns.
ITURHFPROP and PropLab Pro are alternative propagation prediction tools with different modelling approaches. VOACAP is the most commonly used in the amateur community.
Finding a local repeater — or one near your travel destination — is a common need, especially for VHF/UHF operators.
RepeaterBook (repeaterbook.com) is a comprehensive, community-maintained database of repeaters worldwide. You can search by location, frequency, band, access tone (CTCSS/DCS), or features (such as Echolink, IRLP, or DMR). RepeaterBook also provides a mobile-friendly interface and API access for app developers.
ARRL Repeater Directory covers repeaters in North America and is available as both a printed book and an online tool (for ARRL members).
Heard.app and similar community tools are newer platforms that combine repeater databases with real-time activity information — showing not just where repeaters are, but which ones are actively being used.
IARU band plans — The International Amateur Radio Union publishes band plans for each of its three regions. These define the recommended frequency allocations for different modes (CW, SSB, digital, FM, etc.) within each amateur band. Your national amateur radio society's website typically has the band plan for your region, and the IARU website provides the master reference.
National frequency allocations — Licensing authorities in each country define which frequencies are available to amateurs and at what power levels. These can differ from the IARU band plan. Check your national regulator's website for authoritative frequency allocation tables.
The amateur radio web community has built calculators for almost every common design and operating need:
Antenna calculators — Calculate the dimensions of dipoles, verticals, ground planes, J-poles, Yagis, and other antennas for a given frequency. These range from simple wire-length calculators to more sophisticated tools that account for wire diameter and velocity factor.
Coaxial cable loss calculators — Enter the cable type, length, and frequency to calculate signal loss. This is essential when planning a feed line run, especially at VHF/UHF where cable losses are significant.
Grid square / Maidenhead locator tools — Convert between latitude/longitude and Maidenhead grid squares. Many include an interactive map where you can click to find your grid, or enter a grid to see it on the map.
Great circle maps and bearing calculators — Calculate the beam heading and distance from your station to any other point on the globe. Great circle paths are the shortest route between two points on the Earth's surface and determine the correct direction to aim a directional antenna.
Resistor colour code calculators, Ohm's law calculators, and LC resonant frequency calculators — Basic electronics tools that are handy during homebrew projects and troubleshooting.
Decibel (dB) calculators — Convert between power ratios and decibels, calculate effective radiated power (ERP/EIRP), or determine signal-to-noise ratios.
Logbook of The World (LoTW) — The ARRL's electronic QSL confirmation system. Operators upload digitally signed contact records, and when both sides of a contact are present, the QSO is confirmed. LoTW confirmations are accepted for ARRL awards (DXCC, WAS, VUCC, etc.) and increasingly for other award programmes as well. Access is through the LoTW website and the TQSL signing application.
eQSL (eqsl.cc) — An online QSL card exchange. Operators upload log data and can design and send electronic QSL cards. eQSL confirmations are accepted for some awards but not for ARRL awards.
Club Log (clublog.org) — An online log hosting and analysis service popular with DXers. Club Log provides DXCC standings, DXpedition log search, league tables, propagation statistics, and a QSL matching service (OQRS — Online QSL Request System) used by many DXpeditions.
QRZ.com Logbook — QRZ hosts an online logbook where you can upload your contacts and confirm QSOs with other QRZ Logbook users.
Google Earth / KML overlays — Several amateur radio tools generate KML files that can be loaded into Google Earth to visualise great circle paths, antenna patterns, grid squares, and other geographic data relevant to radio operating.
Grid square maps — Interactive maps showing the Maidenhead grid square system overlaid on a world map. These are useful for VHF/UHF operators chasing grid squares and for understanding the geography of your contacts.
Azimuthal equidistant map generators — Generate a map centred on your station location showing true beam headings to any point on the globe. These maps are useful reference tools for any station with directional antennas.
Amateur radio societies — Virtually every country has a national amateur radio society (ARRL in the United States, RSGB in the United Kingdom, DARC in Germany, JARL in Japan, RAC in Canada, WIA in Australia, and many others). Their websites are primary sources for licensing information, band plans, contest rules, and educational materials.
DX clusters — Web-based DX cluster access allows you to see real-time spots of stations on the air without installing dedicated cluster client software. DX Summit (dxsummit.fi) and DXWatch (dxwatch.com) are popular web-based cluster interfaces.
Contest calendars — Websites like the WA7BNM Contest Calendar (contestcalendar.com) maintain comprehensive schedules of upcoming amateur radio contests worldwide, with links to rules and log submission information.
Tip: Bookmark the tools you use most frequently. A well-organised browser bookmark folder for amateur radio resources saves time and keeps your most-used tools a single click away.