About the Project

The Idea(Edit)

For quite a number of years, VK3VS has been investigating software based repeater controllers. It started off using a PicAxe 08m, then went onto a Picaxe 18M2. These worked great with 20mA current draw. The 08m controller gave a simple control for PTT, RX indicator, a subtone enable, a PTT for link radio and a CW ID. The 18M2 gave all this, plus extra pins for fans and battery voltage monitoring and so forth. While These were fun and worked, they were still very limited.

Then along came the Raspberry Pi - Great, a embedded PC that draws around 80mA at 12V. Perfect. Or so I thought.

Initial Attempts(Edit)

Version 0.1(Edit)

First of all there was an attempt using the Gpio's and a sound dongle running inside a bash script. This proved to not be very efficient as the script was limited in its ability to make intelligent decisions. And generating more was a pain.

Version 0.2(Edit)

The second attempt came to me after I had set up a PBX using asterisk. reading some old documentation, I found a program called app_rpt that run under asterisk 1.6, It took several goes to compile the software under Pidora, as asterisk was designed for red-hat based systems. I got it running, however the audio was very broken and there was no way to control the radio ptt as there was no parallel port.

Version 0.3(Edit)

I found Jim Dixons varient of app_rpt as a fork from the origional as asterisk had decided to not include it in future releases, he had forked it an added the chan_usbradio driver which used gpio's on the sound fob for the control. This I thought would work, so again I tried compiling it on Pidora. Well it worked, but again audio was broken but I could control the radio!

Version 0.4(Edit)

After reading more and more about app_rpt and chan usb, the common consensus was the Raspberry Pi did not have the horsepower to do DSP. so I went looking at the Simple USB channel for a way of getting the radio to work without broken audio. See one of the problems is, the later kernels that run do not use OSS, instead they use alsa. so I thought the broken audio problem was the Alsa-OSS emulation, even though it was at Kernel level. I compiled simple usb and damn. still broken audio.

Version 0.5(Edit)

I decided to purchase an Odroid U3, to attempt to compile it. After months of mucking around to get kernel source, as I needed to compile Zaptel and incorporate the oss emulation into the kernel, I made a head road. the software compiled, with some ancient hacks to deal with udev and a piece of software that did not know udev existed, it ran, and clean audio. Now the Odroid takes a dump on the Pi (and even the Pi2) on specs, but is cheap. however a little power hungry. Thought this is better, and possibly the way forward.

Version 0.6(Edit)

Not content with a couple of Pi's sitting there not doing what I wanted them to do, I had another go... This time, I thought, I wonder if I make a custom kernel, will the thing work. So, I decided to use raspbian, as it is written aimed at the Pi. I stripped down the kernel, removing anything that I did not need and stuff I thought would make a pain in the neck out of itself. In particular power scaling. Then I run into another problem. The kernel has had some more ancient stuff removed from it, which means zaptel would not work ever.... so I had to think dahdi (same thing different name), but lucky for me, the source of app_rpt had this already built in to replace zaptel. 23 hours of compiling later, it was born. My Repeater was born on the Pi. the usb audio was a little broken, but the simple audio was flawless.


After it worked, the idea came to me, well now it works, why not use the linking capabilities as well. And there you have it, the VK repeater link was born. Version 1 was released not far after this idea, which had a heap of scripts to co-ordinate connections. The first nodes being VK3VS to VK7DB, nodes 100 and 101 respectively.

Initial Thoughts(Edit)

There has been quite a lot of interest sparked by playing with this stuff, but as always with any projects, there is some that are quite loud in their jealousy. To quote a glorified CB technicians comment via email:

" Most of Matts ideas are crap and the rest are mediocre at best. "

Think I'll put this little project in the mediocre category.

Main page - How it works