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 Contact him at [email protected].

A little mention

Christmas reading time, Sprat 161 popped through the letterbox in this mornings post. I see Graham (G3MFJ) gave me a little mention about the TDA2003's that I recently had come across, he had decided to grab a batch for G-QRP members sales:

What interests me about this chip, as well as being a high powered 10W audio Amp, plenty of circuits which are available on the web. The TDA2003 has also been used in VLF PA design Amateur projects. From G3XBM:

Also at 73KHz The Heyphone John Hey (G3TDZ):
I emailed John recently about the TDA2003 and  he reckons that they will work at 137KHz depending on manufacture? Time to get testing a few on the end of a signal generator..

Steve, G1KQH, is a regular contributor to and writes from England. Contact him at [email protected].

Well, No Magic Today

... it seems. It really does take an extraordinary amount of F-layer density to reflect rather than refract 6m RF. With this afternoon's somewhat late arrival of an earlier CME, perhaps tomorrow's F2 spike will be higher.

The global ionospheric (foF2) map today, around 1100 local time, shows a critical frequency of about 12MHz over central North America. This is the frequency at which RF, when shot straight up, will be reflected straight back to earth. This number can generally be used to find the F2 MUF when multiplied by 3.6, which, in today's case would be around 43.2MHz.

The highest F2 MUF that I heard today was, very briefly, 43.400MHz...Spanish...from where I have no idea but likely from Central America or Florida.

With the solar flux continuing to remain high, so are my hopes for the next few days but I suspect that any openings could be missed, should you blink!

Steve McDonald, VE7SL, is a regular contributor to and writes from British Columbia, Canada. Contact him at [email protected].

Another year gone…

Today I celebrated my birthday and reflecting on the past year I realised just how much I have achieved during my first year as a bona fide radio amateur.

While I gained the foundation licence back in September 2013 it was only at the start of the year that I took possession of my first proper radio and began my first real forays into the hobby. That is not to say the end of 2013 weren’t without its highlights, remember ICube-1?

While the foundation level licence gave me access to most bands, be it at only 10W, I was not content to stay as M6GTG. I passed the intermediate in May (2E0NRD) and finally got the full licence in October (M0NRD) and have slowly been honing my operating skills.

I competed for the first time in the RSGB UKAC and other VHF/UHF contests. They have proved to be an enjoyable and educational activity. The structure exchange helped me overcome my initial microphone shyness and the goal of improving my score each week to become more competitive forced me to improve my set up.

Construction of a headset interface and the addition of a foot switch were simple projects as was the building of a simple but effective Moxon antenna for 6m (blog post). This together with a permanent antenna pole, rotator system and upgraded coax all have helped me improve and learn. I even tried my hand at some portable operating with varying degrees of success. I have received some invaluable help and advice from people, especially Robert G1ZJP (M1MHZ) The results for the year have been coming in and I am very happy with my final positions in the various bands for a first timer and hope to be more competitive next year. .

HF operating proved initially off putting, plagued by QRN/QRM and my initial microphone shyness I veered toward the more noise immune data modes. I built a data mode interface and have had a fair degree of success with PSK/JT65 and RTTY as dabbling with a few other modes and over the last few weeks I have experimented with FreeDV and find it fascinating.

As I have become more confident I now operate voice more often and now regularly give points away on contest weekends because I like the short formalised exchange. Indulging in small talk in normal contacts is something I am not good or comfortable with but as I’ve got to know local operators I have started to join in the local nets and art of conversation is becoming easier.

The High Altitude Ballooning (HAB) has taken a back seat at present. I still have active plans to get a flight up with my own payload and have given a number of successful talks to local clubs over the year which I have enjoyed. Missing the UKHAS conference was a bitter disappointment but I still track flights and I hope to reinvigorate this interest in the spring as I get back up to speed with recent developments. 

Due to time constraints I have also mothballed plans for numerous construction projects based around the Arduino. Last months rearrangement of the shack should allow me to finally get around to finishing them.

Operating the JOTA station GB2FFC for a local scout group was very rewarding. The write up from this blog was included in the latest RSGB Radcom magazine and we hope to do it again next year. Being asked to contribute content to the website came as a surprise and thanks to all those who have commented on my ramblings.

Another rite of passage was managing to repair my first rig, an elderly TR9500, yes it was only a modest achievement but a massively satisfying one and it has given me some confidence in purchasing second hand equipment in the future.

As well as building up the shack and continuing to improve my setup and operating I have some specific aims for next year...

Make a proper satellite contact
Satellite reception and tracking is something else that has been neglected recently, though I am still decoding FUNCube-1 telemetry daily.

Make a meteor scatter contact
I attended a fascinating presentation at the Spalding and District ARS by Robert G1ZJP about Meteor Scatter operating just before the Perseid meteor shower. I have made a couple of attempts since including during the recent Geminid shower and while I can receive signals no problem I have yet to make a successful contact. It is definitely on the to-do list but I may need to increase the power output, maybe even investing in some amplifiers and better antennas who knows it could lead to attempting some EME!

Make a proper SOTA/IOTA activation
Next year I will be holidaying in Scotland on the Isles of Skye and Islay so want to make a better attempt at operating in these more remote operating than I did this year. I also want to take a radio up a mountain!

Become more involved locally
I joined the South Kesteven ARS last year and regularly communicate with members of the nearby Grantham ARC. There have been suggestions of operating special event stations as well as repeating the JOTA event. I enjoy the meetings and conversations and is nice to bounce ideas off each other and hope to be more involved in organising activities.

Anyway, still a few hours of my birthday left so off to enjoy a wee dram or two and a slice of my birthday cake made by loving XYL

Andrew Garratt, MØNRD, is a regular contributor to and writes from East Midlands, England. Contact him at [email protected].

Apple – Panorama documentary

Last week, BBC's Panorama programme did a frightening documentary on factories used by Apple in China and on their tin supply chain in Indonesia. If such poor conditions are used by Apple, many other products will be produced in even worse conditions. As a user of Apple products I am appalled.

See Panorama, Apple's Broken Promises .

Of course, we in the West milk the low costs that such poor working procedures/conditions permit. With time, conditions will improve and the West will look to other low cost manufacturing areas for our low cost products. Sadly, our greed feeds this process.

Frighteningly, other products we buy are probably made in places that are far worse.

Andrew G6ALB tells me of a friend in the automotive industry who visited a Chinese supplier where he found workers using ordinary sun glasses to protect eyes from welding gear. After 6 months  the workers were totally blind. So they just got fresh workers to replace them!

Thanks to Steven G7VFY for most of this information.

UPDATE 1740z:  Sadly many (most?) of our electronics components will be made in sweat shops in the Far East. It is very hard to get away from this problem.

Roger Lapthorn, G3XBM, is a regular contributor to and writes from Cambridge, England.

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