WSJT (amateur radio software)

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WSJT is a computer program used for weak-signal radio communication between amateur radio operators.[1] You can find out more about it, including its history, at Wikipedia.

To use, you will need to download the program and have a method of connecting your computer to your radio.

WSJT-X program interface

Screenshot showing the WSJT-X main program window with the waterfall above.

The main program area has three 'sections' - the Read Activity on the left showing everything heard during the transmit/receive sequence across the full frequency range; the Rx Frequency showing what was sent, or was heard on the specific receive frequency selected; and the lower section with details and settings.

There is also a waterfall display that shows you what is heard across the full frequency range being monitored. Areas in yellow and red indicate strong signals, while areas with very light blue indicate faint signals.

Communication modes

The WSJT software supports several digital modes, including MSK144, WSPR, and JT4.


This mode is named after its developers, Steven Franke (K9AN) and Joe Tayler (K1JT), and the fact it uses an 8-frequency shift keying format. It was introduced in 2017 and it is considered a fast operating mode, as the transmit/receive sequence is 13 seconds with a 2-second break in between sequences. Transmissions always occur on upper sideband (USB) regardless of operating frequency.

Here is an example of how FT8 sounds. The first part is one station transmitting; the second part is receiving across the entire frequency range being monitored. Note that this may be loud, so check your speaker volume or lower the player's volume before clicking play.

QSO format

A QSO is essentially in 5 parts:

  • A station transmits CQ with its callsign and gridsquare info
  • Another station reports that they hear you and provide their call sign, gridsquare info and a signal report
  • The first station replies with a roger and provides a signal report back
  • The second station replies roger roger, and sends 73
  • Last, the first station responds 73

Example QSO

An example of a QSO using WSJT in FT8 mode.

To the right is an example of how this looks within the WSJT software. In the example we can see the QSO:

    • JA9BFN is calling CQ. DX means they're looking for distance contacts (outside of Japan). The software knows this station is in Japan, and shows "Japan" to the right of their CQ for our reference.
    • K8AMH is responding and providing the first four of his gridsquare
  • K8AMH JA9BFN -24
    • JA9BFN heard and is providing a signal report of -24 db (in this case, the lowest we can generally get and still be heard)
  • JA9BFN K8AMH R-17
    • K8AMH acknowledges (roger) and provides a signal report of -17 back
    • JA9BFN acknowledges (roger roger) and says 73
  • JA9BFN K8AMH 73
    • K8AMH says 73

When calling CQ you can call generally (CQ K8AMH EM12), you can specify a state you are trying to make a contact with (CQ HI K8AMH EM12 for Hawaii, as an example), or you can specify you're trying to make distant (DX) contacts (CQ DX K8AMH EM12).

Monitoring your transmissions

Some amateur stations forward information on what they are hearing to an online website called PSKReporter. The site allows you to see on a map what stations have heard you, and you can filter what is shown based on bands and modes, among other options. You can access the site at


  1. Wikipedia contributors. (2018, December 21). WSJT (amateur radio software). In Wikipedia, The Free Encyclopedia. Retrieved 08:09, January 30, 2019, from

External links