JS8Call – An overview for new users


Back in March of 2018 I managed to get involved in the testing of some new software for Amateur Radio. I joined a very small team of Operators who were mainly in the USA but also three in Europe, including myself. This software was called FT8Call, the original name of what is now called JS8Call.

As you may have already deduced from the original name of the software it’s a new digital mode that is built upon the popular weak signal digital mode FT8. If uses the same modulation as FT8 allowing it to be decoded at -24Db, and it also uses the same 15 second timer to send out its messages.

It is there that the similarities end though, because unlike FT8’s simple Signal Report exchange format, JS8Call allows free text keyboard-to-keyboard communications.

Hardware Requirements

You don’t need the latest high-powered computer to run it. It will run as Happily on the Raspberry Pi as it does on the latest high-end laptop. Supported operating systems include various distros of Linux, Windows 10 and MacOS X. That said there are also many operators in the pre-release test that are running it on older operating systems such as Windows XP and Windows 7.

Like any other computer based digital mode you also need some way of connecting the computer to the radio via a sound card interface of some kind. On my PC and Icom IC-7300 this is done with one USB Cable for CAT Control and the Sound Interface provided in the Radio.



Installation on the supported operating systems is a simple case of downloading and running the installer package. Currently while the software is in pre-release beta testing in order to get to the download you need to join the JS8Call groups.io group, this is because while the software is being developed each version has a limited lifespan of 2 weeks or so, at the end of that time it will not run. So being a member of the group means you will receive notifications of when the next version is released so you can download the latest version which includes bug-fixes and new features. Once JS8Call reaches a stable release it will become available to download from the main website.

User Interface

The user interface is laid out well and does also work quite well on a touch screen interface as well as with a mouse. The main window is split into the Band Activity pane (showing messages you have decoded), Incoming Message Activity Pane, Call Activity pane (showing the list of callsigns you have heard), the Message box (here you will enter your outgoing messages) and the Waterfall at the bottom giving you a visual indication of where the signals are in the passband – you can also select the frequency offset you want to use here.

Using JS8Call

So lets get down to actually using the software. Once installed there are a couple of things you need to set up. First enter your callsign on the General/Station settings page. Then entry your Maidenhead Grid locator and customise your Station messages, and finally set up your radio interface and select the sound card to use.

Back in the Main User interface calling CQ is as simple as clicking on the CQ button, JS8Call will put your CQ message in the message window and send it at the start of the next 15 second time frame. Once you receive a reply you can click on the station’s callsign in the Call activity pane and then type your message into the message box and click send, JS8Call will automatically add your callsign and the selected station’s callsign to the message and send it.

That’s all there is to it. There is some automation like the ability to set it up for your station to reply to directed commands/messages automatically but the actual QSOs are comtrolled by the operator with free text or the use of Saved messages which can be pre-defined by the user. There is also a “Heartbeat” function that will send out your callsign and grid locator at user-defined intervals. This is not a CQ call but a mechanism that lets others know your station is on the air and they can call you direct, or maybe send your station a relay command to pass a message to someone that they cannot hear.

The Power of Low Power

The great thing about this mode is that it can be decoded at -24dB. Which means that you don’t need to run your radio at full power to chat with a DX station. During the recent QSO party weekend I was able to set my IC-7300 at minimum power (0% which gave an output power of approx. 350mW) and have a conversation with Julian OH8STN in Finland over 1300miles away. I was also getting acknowledgments to my “Heartbeat” from stations in North America during the evening.

What’s the Cost?

 JS8Call costs nothing, it’s based on open source software and although parts of JS8Call contain code that Jordan KN4CRD owns the copyright to he has assured us that he will never charge for the software.


JS8Call has come on in leaps and bounds since I joined the test team back in may. And its evolved into what’s going to be a great mode for communication over long distances using relatively low power. Jordan has done some fantastic work and is very supportive of new users on the groups.io groups and is happy to accept requests for improvements and new functionality. He’s doing Amateur Radio a great service and I can’t thank him enough for that.

If you havn’t yet tried JS8Call then consider giving it a go, there are a lot of users out there who are happy to help you get up and running, and there are a few facebook groups you can join and of course the JS8Call website contains lots of quick user guides and links to all the documentation etc. And you can always give me a shout and I will be happy to help!

Useful Links


http://js8call.com– The Official JS8Call Website

http://groups.io/g/js8call – JS8Call on Groups.io

https://docs.google.com/document/d/159S4wqMUVdMA7qBgaSWmU-iDI4C9wd4CuWnetN68O9U– JS8Call Documentation

https://www.facebook.com/groups/PortableDigitalQRP/– Portable Digital & QRP Group on Facebook

https://www.facebook.com/groups/ft8call/– JS8Call User group on Facebook


2 thoughts on “JS8Call – An overview for new users

  1. IN Using js8call how can one send a message to a particular station, and have him pick that message up later… just getting used to this new mode. yes the lower power levels are amazing !

    1. Hi David, yes you can. Select the callsign to send to in the heard list on the right, and then in the message box enter MSG followed by your message. then send, once received (you will get an ACK) the message will be stored in that station’s inbox.

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