RPiGate again

For a few weeks I have been attempting to use an RTL-SDR and a raspberry Pi 2 as an APRS iGate. Dutifully following a number of tutorials I failed to ‘Kalibrate’ the dongle several times and so put it to one side. Today however I have managed to get the thing running. Not with the original tutorial but with a different application called ‘Direwolf’.

There are quite a few clever sods kicking about and the guy who pulled this together is no exception. John Langer,WB2OSZ has not only produced a cracking application but also one of the most straightforward and detailed installation documents as well. What I particularly liked was the way that there was a step followed by an explanation of what the step was meant to achieve. I’m no great linux fan, partly because I don’t understand what the hell is going on and more importantly for me, why its not doing what I thought it should do and why. This small success may point me more in that direction though.

More to the point see. I told you it was working!


speed = distance over time


Speed does = distance over time. In terms of CW my speed is currently around 12wpm with a character speed of around 20wpm. I have been at a distance from a qso for over a month now and I am experiencing what is called a plateau. Or is this my natural speed?

If I go for a run, I know I can run at a certain pace for a certain distance. Nowadays no amount of training will get me down to what I could once do when I was in my teens (back then I could do around 1 to 2 minutes quicker for a mile). This was the same back then. I have a capacity and I know it well. Is the same true for CW?

Can I only do a certain speed?

How do I find a natural speed and maintain it? (Overtraining is a crime!)

My normal excuse is I need a new pair of trainers. Surely I need a new morse key, right?

Minima Digital Board

After procrastinating for a very long time I finally summoned up the ‘whatever it was I needed to summon up’ to get a move on with the Minima transceiver. I planned on tackling the digital board first as it seemed logical. It did however need me to solder an Si570 onto the board without any solder paste. So it was going to be a bit of a struggle.

The method I chose was to put a healthy load of flux on the pads and a blob on both of the ends. Align the chip then solder one end, applying a small amount of pressure onto the chip. Then the other end, then back to the first and then to the second again. Making sure I had seated it correctly. after that the other pads seemed dead easy.

The result was that it worked (I think). Although I am unsure as to why is does stay on a single frequency. This will need a bit of looking at. Here’s a very brief video.

Its chilly in here

I’m going to use it as an excuse but really it isn’t….The shack is cold (Its a garage really) and the thought of going in there really wasn’t that appealing. We’ve had some pretty miserable weather since the end of November and its been a full time effort just to go out and walk the dog. I’d also taken on the mechanical build of the SatNOGS project as part of the club project and that took up way more time that I thought. Now that’s finished it was time to get on with a few things of my own.

First things first, looking at the Minima digiatl board it seemed like something that could be built and tested in an afternoon. I was nearly right, in the interim I had lost / put in a safe place, the LM1117 3.3v regulator and didn’t have a spare (Like I keep spares of stuff like that, I’m not a professional you know).

Minima Digital Board

Built what I could and here is the result. Stone me it actually powered on an worked first time, but there isn’t any power to the Si570 and that’s a whole different ball of solder.

Onwards and upwards

Open Web RX

If, like me you have an rtl dongle, there is another ‘thing’ you can do with them that I bet you never knew. Ok you did but I’ll bet all of you didn’t know. Its called OpenWebRX


You can also arm yourself with one of those old netbooks you’ve got loafing about in the corner and put it to use into the bargain.

To tell the truth I’d not heard about it until Daniel, 2E0DNX mentioned something in passing as I was driving him back from the club night last Monday. I can’t remember what started it but we got onto the subject of putting receivers on the web a la WebSDR and the well known Hack Green SDR. This time, as we are both cheapskates, it was around the use of the cheapo dongles.

So, after downloading a copy of Lubuntu (A lightweight ubuntu distro) I installed it onto an old netbook. I thought I followed the instructions on the website and but I hadn’t and after a false start with some rubbish spelling had a receiver running on the local host. I did get some pretty speedy support from the developer though who helped to narrow down my incompetence.

Getting it on line is a little more complicated and needs a bit of fettling. In order to get it listed on the site it needs a web presence. To get that you can pay for it and host it or you can be a cheapskate and use a service like N0-IP.  Guess which route I went? They provide a web address that you can use and some really handy instructions for linux installations, if, like me, its not a natural environment to work in but you can largely follow instructions.

After all instructions followed correctly (there are no spelling mistakes in your config file 😉 ) then the last thing to do is make sure your router lets the traffic through (port forwarding). This can be a pain if you’re on BT like me and can lead to no end of frustration that was eventually fixed with a new, non BT router. I’ve got my head round this and will now look to set up a more permanent installation, perhaps with a RPi2 if its got the right mojo.

All in all you’ve got to hand it to people who set out these environments as they are becoming a great way of distributing amateur radio to a wider audience. Thanks Andras, HA7ILM and well done!