What WSPR is

WSPR (pronounced “whisper”) stands for Weak Signal Propagation Reporter. It was developed by Joe Taylor, K1JT, the same person behind FT8. A WSPR transmission takes about two minutes and carries only three things: your callsign, your grid square and your transmit power.

Stations around the world listen, decode what they hear and upload the reports to wsprnet.org. A few minutes after you transmit, you can see a map of everyone who heard you and how strong you were.

Why it’s useful

• Test an antenna: put up a new antenna, run WSPR for an evening and compare the map with the old one. It’s real data, not a guess.
• Learn propagation: watch a band open and close through the day, and see the grey line effect for yourself.
• Very low power: WSPR is decoded at signal levels far below what you could ever hear. A watt or less regularly crosses oceans.
• Receive-only works too: you can just listen and report others, which is a great way to check how well your antenna hears.

How to get on

• WSPR is built into WSJT-X, the same free program used for FT8.
• Set your callsign, grid square and actual power in the settings.
• Choose a band. Dial frequencies on USB include 14.0956 MHz on 20 m, 10.1387 MHz on 30 m, 7.0386 MHz on 40 m and 3.5686 MHz on 80 m. Signals sit 1400 to 1600 Hz above the dial.
• Set the transmit percentage, often 20 to 30 percent, so you spend most of the time listening.
• Turn on uploading so your decodes help others too.

Good practice

• Use low power. Five watts is plenty, and a lot less usually works.
• Make sure your clock is accurate. Like FT8, WSPR needs your computer’s time within a second or so.
• Keep audio levels clean. Overdriving the radio splatters your signal across other WSPR stations.
• Don’t leave a transmitter running unattended. You’re still the control operator.

Where to go next

• FT8: What It Is
• FT8 Setup
• Antenna Testing
• PropMap

Last updated October 2026.