Sending APRS messages to Twitter via the International Space Station

HamRadioTweets is a service that was originally developed and operated by Bruce Sutherland KO4IN. The idea behind his work was inspired by conflicts overseas, it was meant to be a proof of concept on how to get your message out if your government restricts your internet access.

Mr. Sutherland originally created the software as a means to send messages over satellite such as the International Space Station and others that have on-board APRS Digipeaters. I am however getting ahead of myself.

Sometime in late 2014 I had begun learning to write software in ruby, an interpreted programming language, I had quickly found how easy it was to work with sockets allowing me to interact with servers on the internet. I wanted to merge my programming with my love for ham radio. This is when the APRS-IS network came to mind.

I wrote a small ruby gem allowing me to interact with the APRS-IS network, I could see all traffic on the network and filter it in any way I saw fit. Naturally I thought I could add some type of service to the APRS network. There was already a ruby gem that simplified posting to twitter so I figured an APRS to twitter gateway would be a good way for me to hone my new found skills.

After a little research I found that Mr. Sutherland had already developed an APRS to Twitter gateway and even presented it at a computer security conference known as Defcon, However to my dismay I found that it had been offline for some time with what seemed to be no sign of a return. I wasn’t able to find any source code for the software, all I knew was that it had been written in Python.

I thought to myself, if he can write it in Python then I can write it in Ruby. After just two short hours of work I found myself with a simple test server that did exactly what I wanted it to. It would register itself to the APRS-IS network with the callsign designator ‘TWITR’ this would allow anyone from any APRS gateway send a message to twitter by sending it to that callsign.

Later I had contacted Mr. Sutherland and asked him for permission to take over the website and development, which he greatly obliged to and gave me full access to the domain. I began running the server 24/7 on November 23rd of 2014 using the code that I published as an open source project.

The service is back online and available for Amateur use, I plan to continue development in my free time while working on additional services that we could add to the APRS network.

Software Source Code:
Github Repository:

Harold Giddings, KRØSIV, is a special contributor to He is a Ruby programmer and maintains the website Signals Everywhere. Contact him at [email protected].

3 Responses to “Sending APRS messages to Twitter via the International Space Station”

  • Fahim:

    Just discovered your vaouris posts on the web including YouTube videos. I’m a new owner of the kx3 and loving it. I do find it a bit confusing because there seem to be many ways to use hardware and software on digi modes and not sure what’s best. I do have an iPad and will follow your advice but you don’t mention if you have the radio in USB mode or Psk d mode. Please clarify. Also, when I plug a 3 pole plug into the mic jack it immediately triggers the ptt so how are you avoiding this to allow you to use the radios vox function or ptt through the mic jack? I’d appreciate your suggestions.Tnx73Rick, w2 Jaz

  • Harold KR0SIV:

    I don’t have my radio in any kind of mode, for the purposes of this experiement I just used a baofeng radio with a soundcard modem from my cellphone to create the AFSK packets.

    If your radio is immediately keying there is either an issue with the radio or the cable. I had to make my own cable using a pin out I found online to prevent this.

    However with these cheap radios the best bet for packet is to use a bluetooth adapter. This is the only thing I will use on an HT these days and it works every time. Well worth the money.

  • James KH2SR:

    I’m an avid 2m satellite APRS user and I was wondering why hams don’t utilize 900mhz & 1,200mhz for APRS satellites? Wouldn’t the considerably higher frequency allow us to utilize much smaller antennas?

    I own a SPOT GPS tracker as well and it works quite reliably even with its limited 0.4 watt RF output on 1,600mhz

    I would think that various companies like Byonics, Argent Data Systems, Fox Delta, & many others could easily produce a 5 watt APRS packet transceiver with an integrated directional patch antenna similar in size to the SPOT GPS Tracker.

    Maybe the next APRS satellite should have an experimental digipeater on the 23cm & 33cm ham bands?

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