Sunday, January 27, 2013

FreeDV codec2 presentation to Home Brew Group

Today at the ARNSW Home brew group, I presented a talk about FreeDV and codec2. Feeling unqualified to talk about how codec2 works, I wrote to David Rowe - the author of codec2 and last week we met up in Sydney where I interviewed David on video and that conversation is included in my talk.

Codec2 is an exciting new low bit rate voice codec that is open source. It is particularly suitable for digital voice over HF radio.

Thanks to Peter, VK2EMU for asking me to speak, John, VK2ASU for videoing the talk, and of course to David Rowe for taking the time to answer our questions on codec2.

Here's just the interview with David without my prattling on before and after:

Sunday, January 20, 2013

Ham radio software on MacOS - try wine

MacOS users sometimes feel like second class citizens with so much great Ham Radio software for Windows and increasingly Linux. But I've found that many of the Windows versions of programs work brilliantly under the Wine windows api emulator. Here's WSPR for windows:

WSPR shows that audio in and out works well. One thing to note is that you run the installer and then must run the installed program which ends up at ~/.wine/drive_c/Program\ Files/WSPR/wspr.exe so I run it by:

  • cd ~/.wine/drive_c/Program\ Files/WSPR/
  • wine wspr.exe

Here's FreeDV receiving:

Here's me transmitting using the display microphone:

Audio actually works a little better than under real Windows where I'm unable to mix USB and on board audio. MacOS seems to have better built-in audio support. FreeDV is simply downloaded as a zip archive of a directory containing the exe and some shared libraries.

WSPRX unfortunately doesn't run by the way.

Building Wine

Windows are displayed using XWindows and for that you need to install XQuartz.

To install wine I recommend homebrew. I'm on MacOSX Mountain Lion and the build gets a link error and I needed to do this:
  • brew update
  • brew doctor # which reports that all is well, if not take advice
  • brew rm libpng
  • brew install libpng --universal
  • brew install wine
So, great work by the wine and hombrew folks.

MacOS X users are not really short of Ham Radio Software

My opening remark gives the wrong impression, there's actually great Ham Radio software for MacOS these days. Machamradio has a great list.

Sunday, January 06, 2013

ARNSW Sunday broadcast via digital voice

This morning VK2JI relayed the Sunday broadcast via digital voice using freeDV. Here's how I received the signal on 7190 from the Central Coast of NSW (I'm in Sydney).

Earlier in the broadcast:

Here's a screen shot.

There is discussion of all this on the digitalvoice google group.

Here is Ed's video of the transmit setup.

Thursday, January 03, 2013

Upgraded to Bigpond Extreme, getting 80Mbps

We aren't on the three year plan for the NBN so I decided to go ahead and upgrade our cable internet to Bigpond Extreme.

Here is how it was before according to speedtest:

And here's how it is now:

So, oddly, ping time is slightly worse from 6ms to 9ms, but download speed is noticeably better going from 26Mbps to 80Mbsp. The experience of loading a web page is very nice indeed.

We no longer have a land line so we pay $110 per month and get 200GB of data. Incidentally, we've just installed a Skype phone - one that doesn't need a computer - and it seems to work very well.

Tuesday, January 01, 2013

Running a temporary syslog server

I'm trying to connect a SIP VOIP device VK2ASU kindly passed me to pennytel but it won't register with them. The device's web interface doesn't give much information but it does have the option to send logs to a syslog server on your network. I've figured out a very simple way to run up a server for temporary use using netcat.

$ sudo nc -ul 514
<13>[SIP]  | NOTICE | allocating transaction ressource 119 19277552-0131122292
<13>[SIP]  | NOTICE | allocating NICT context
<12>[SIP]  | WARNING| info: Name resolution requested.
<12>[SIP]  | WARNING| Doing asynchronous name resolution.
<14>[SIP]  | INFO   | MESSAGE REC. CALLID:19277552-0131122292
<12>[SIP]  | WARNING| OnEvent_New_Incoming4xxResponse!
<12>[SIP]  | WARNING| User need to authenticate to REGISTER!
<13>[SIP]  | NOTICE | allocating transaction ressource 120 19277552-0131122292
<13>[SIP]  | NOTICE | allocating NICT context
<12>[SIP]  | WARNING| info: Name resolution requested.
<12>[SIP]  | WARNING| Doing asynchronous name resolution.

This gets nc to listen to UDP on port 514 and it displays whatever comes in.