EssexPSK – Free PSK31 Decoder Application

New to the world of amateur radio data modes? We can help.

On this page, you’ll find the latest copy of EssexPSK, a free application that lets you decode data signals on your PC.

What is EssexPSK?

It’s a free application that can be installed on your Windows computer that decodes PSK and RTTY data signals received on your amateur radio, and lets you decode and view conversations.

PSK31 is one of the common of the HF data modes, and is a great mode to get started with. Using this application, you’ll be able to decode PSK31 data signals and get familiar with the mode

EssexPSK - The Essex Ham PSK Decoder by M0PZT
EssexPSK – The Essex Ham PSK Decoder by M0PZT


How do I use EssexPSK?

To use the application, you need to connect your amateur radio to your computer – typically, connecting the headphone output to your computer’s Line In socket will do the trick. You can even decode signals by holding a cheap computer microphone in front of your radio’s speaker.

Most of the PSK activity is on HF, so you will need to tune your radio to a suitable frequency and check that you can hear the data tones. The EssexPSK app has a button that lets you view common frequencies.

Download EssexPSK: EssexPSK (1.4MB .exe), or EssexPSK (1.4MB .zip)

The EssexPSK application is deliberately very basic, to encourage newbies to give the mode a try without the hassle or expense of one of the larger PSK31 applications. It only has two settings to control, making it ideal for those wanting to get a feel for PSK and RTTY:

  • One control allows you to select the mode (from a list of common PSK and RTTY modes)
  • The other lets you select which computer soundcard input to use – In most cases, this will be the default soundcard, but if you have multiple soundcard inputs, use the pull-down to select the one that works.

Once installed and running, you should be able to see PSK31 data signals going from top-to-bottom in the Waterfall view. Click on one of streams with the mouse and the little arrow at the top will show the stream selected. Note that the thicker streams indicate the faster PSK63 mode, often used in contests.

Close-up of the EssexPSK PSK31 Waterfall
Close-up of the EssexPSK Waterfall

Hopefully, you’ll find EssexPSK of use and it’ll provide you with a basic feel for what the mode has to offer. If you have any questions or problems, please add a comment in the section below.

Our thanks

The EssexPSK application has kindly been created for us by Charlie M0PZT, creator of the PZTLog logging application, and allows for decoding of PSK31, PSK63, PSK125 and even various RTTY signals. It’s been made available for non-profit use to help people get started with data modes.

The application uses the MMVari engine created by Makoto Mori, JE3HHT


Related links


  1. m0ans 5 January 2017 Reply
  2. M0RLF 28 February 2024 Reply

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