Thursday, June 14, 2018

Australian Government reviewing broadcasting into the Asia Pacific

If you have an interest in having Australia resume broadcasting into the Asia Pacific region again, like we did up until budget cuts resulted in an end to Radio Australia's shortwave services in 2014, I urge you to respond to the review being conducted by the Department of Communications and the Arts along with the Department of Foreign Affairs and Trade.

It closes on the 3rd of August 2018 at 17:00 AEST.

The terms of reference are very broad, seeking to assess the reach of Australia's media in the region, and covering many distribution platforms - they mention television, radio and online.

The striking thing that's changed in recent years is the increased output from China which has in some cases taken over frequencies that used to be used daily by Radio Australia (which of course they have every right to do).

Technical things have changed too:

  • Digital Radio Mondiale has been rolled out in India (although receivers are still not very good)
  • Smartphones and mobile data are much more available in the region
  • Use of home satellite receivers has declined globally as more content moves online
  • Use of shortwave AM radios has diminished but it's interesting to note that there are many new models of radio available.
There are many benefits arising from broadcasting into our region from Australia, perhaps the best defence against Fake News is just the provision of consistent, quality, regular news. Tecsun Radios Australia has a great article on the value of shortwave in the region. 

You can find out more by joining the Facebook group "Supporters of Australian Broadcasting in Asia and the Pacific".

Saturday, June 09, 2018

Fascinating talk by Hans Summers

Thanks to Bill's Soldersmoke blog for this tip. At the "Dayton" (not actually there any more) hamvention this year, Hans Summers gave a terrific talk about his distain for the archaic NE602 based transceivers and how it's time to upgrade the design using modern methods.

I recommend, grabbing the slides and then playing the Ham Radio Workbench podcast episode. You might like to seek in 1hr 20 minutes to where the talk begins. Hans has also published a paper with more detail.

Hans describes in detail how to generate quadrature signals from an Si5351 clock generator. Great stuff.

Saturday, June 02, 2018

FreeDV digital voice story on WIA broadcast via FreeDV

The recursion appeals to me, here is a story about the new FreeDV 700D mode complete with comparison with SSB. I heard the story via the relay over FreeDV 1600 from Adelaide.

Interestingly I find digital voice decoded is more intelligible in a small external speaker than in headphones.

After the broadcast relay, Mark, VK5QI conducted a callback on 700D with stations VK3PR, VK3RV, VK5DGR and VK5APR. We often got perfect signals despite some interesting selective fading such as this on VK3RV.

The broadcast on FreeDV is at 10am Sunday Adelaide time on 7.177MHz.

700D uses much less bandwidth than sideband, here's a waterfall comparison David VK5DGR sent me this morning.

One thing to note (it confused me) is that FreeDV uses the same sideband as normal voice on each band. This is unlike other digital modes which generally use upper sideband everywhere.

Installing FreeDV 1.3 on Ubuntu or Debian

Not everyone likes to build from source. You can download and install FreeDV 1.3 (which you need for the new 700D mode) as follows:

Download these files:

In a terminal go to the Downloads folder and:

sudo dpkg --install libcodec2-0.8_0.8-2_amd64.deb
sudo dpkg --install freedv_1.3-1_amd64.deb