Playing radio ..

So today I decided to spend some time playing radio in the FJ. I drove down to the Canadian Aviation Museum which is situated along the Ottawa River to watch some light aircraft come and go as I played around.

There was no real purpose of today’s radio play other than to get out and actually fiddle around.

I decided to convert my netbook entirely to Linux as I have long been a fan of the operating system. My usual choice would have been Mandrake (Mandriva) but Ubuntu was already installed (previous project) so I just went with it.

My first order of business was to install Fldigi which was as simple as:

$ sudo apt-get install fldigi

After installing Fldigi and configuring both my USB-to-serial adapter (PL2303) and my Creative USB sound card, I was up and running! I might add that configuring the USB-to-serial adapter was a pain in the butt because I am not entirely familiar with the Ubuntu convention for /dev/ devices. Turns out my USB adapter was assigned to:

/dev/ttyUSB1

With Fldigi up and decoding data, I decided to turn my attention to the original premise of switching over to Linux: soundmodem

Soundmodem is a Linux kernel module which allows one to use their soundcard as a software KISS-TNC. The software TNC is integrated at a very low level, allowing for some pretty sophisticated radio-networking which is generally not possible (or very poorly implemented) in other systems.

$ sudo apt-get install soundmodem
$ sudo soundmodemconfig

The soundmodemconfig utility allows one to configure the soundmodem module to modulate and demodulate AX.25 ASFK intelligence using the standard 1200Hz and 2200Hz (mark and space respectively). First you must create a configuration for your radio / computer. This is where you will select your sound-card driver and the PTT driver.

Mode: alsa
ALSA Audio Driver: plughw:1,0
PTT Driver: /dev/ttyUSB1

Next, you create a channel for the intended purpose of your packet radio work. In my situation, I wanted to use APRS so I created Channel 0 with the following settings:

Modulator
Mode: afsk
Bits/s: 1200
Frequency 0: 1200
Frequency 1: 2200

Demodulator
(same as above)

Packet IO
Mode: KISS
File: /dev/soundmodem0

Once the soundmodem is configured, you can test it out by clicking on Channel 0 and then selecting “Diagnostics” in the menu. Next was to install xastir (an APRS visualizing program).

$ sudo apt-get install xastir
$ sudo xastir

With xastir running and my radio tuned to 144.390MHz I was soon decoding AX.25 APRS packets. I manually entered my coordinates into xastir and fired off an APRS packet by selecting: “Interface > Transmit Now!” and sure enough, I was seen on aprs.fi shortly after.

Success! Now all I have to do is get my Garmin 62S to properly communicate with the Ubuntu machine. Its been a pain in my arse thus far – I do NOT like the changes Garmin made to their interface.

The next mini-project I had set out was to play around with pskmail a bit. For those who are unaware, pskmail is a system similar to sailmail or winmor which allows a radio amateur to send and recieve emails (and more in the case of pskmail) via HF. This is a pretty cool concept that I would like to play around with, so, I spent a couple of hours getting pskmail up and running.

Unfortunately, the installation and configuration of pskmail is total crap for linux. I was extremely disappointed to see the pathetic installation package which pskmail currently uses. I can appreciate Java applets, etc. however in this case, I firmly believe that a proper Linux binary is in order. Alas, I digress.

After much screwing around with getting a working Java run-time environment which would properly virtualize the pskmail client, I was up and running. I still have some learning to do with this system, however, it seems promising so far.

I’ll be looking into winmor as well – I seem to recall there was an effort to port this over to Linux as a binary. I’ll keep you posted on what I find.