New FreeDV 700D HF Digital Voice Mode

Many amateurs are experimenting with various digital voice modes, such as Yaesu System Fusion C4FM, D-STAR and DMR etc, mostly on the VHF and UHF bands. Did you know, however that there is also a digital voice mode for HF radio operation that was specifically designed by amateur radio experimenters?

FreeDV, based on a fully open source codec known as Codec2, has been created by David Rowe VK5DGR in collaboration with a team spread across the globe.

FreeDV is enabling amateur radio enthusiasts to experiment with new open source digital based voice transmission techniques on the High Frequency (HF) bands.  While text based HF digital modes are common, FreeDV is the first new VOICE mode for HF since SSB was introduced in the 1950s and 60s.

New version of FreeDV – 700D announced

Over the past 18 months or more, David and his team have been busy working to improve the lower bit rate versions of FreeDV. The original system, released as FreeDV 1600, was based on a 1600bits/sec data stream, but was a few dB off being equal with SSB. Now, David is pleased to announce that the new FreeDV 700D mode is ready for wider trials.This new version uses a 700 bit/s speech voice codec, powerful forward error correction, and a new modem to send digital speech over HF radios.

What is really exciting however is that testing of FreeDV 700D has demonstrated that it is outperforming SSB on poor channels! Here is a demo of SSB, followed by FreeDV 700D, on a poor quality 3,200 km path between Adelaide and the Bay of Islands, in New Zealand.

Where can I get it?

You can run FreeDV using any PC set up for digital modes, using the FreeDV 1.3 GUI program, which you can download from freedv.org.

Where can I find FreeDV activity?

Australian FreeDV activity is typically on 7.177 and 14.236 MHz. You can also coordinate FreeDV QSOs using the FreeDV QSO finder at qso.freedv.org

So why not try the new FreeDV 700D mode, and join us in experimenting with it on the HF bands!

Next AREG Meeting Friday May 18th – RF Connector Myths Dispelled

Like most Amateur Radio operators your shack probably contains a plethora of different RF connectors linking radios to tuners, antennas, amplifiers, receivers etc. Have you ever wondered why there are so many varieties? Have you ever wondered which ones are the right ones to use in a given situation? Do you run high power and have you considered whether your connectors are up to the task, especially if you are dealing with high VSWR leading towards your tuner?

Our guest speaker this month is Matt VK5ZM, who will take you through the different types of connector and provide an insight into their design and the criteria to consider when choosing them for your installation.


The meeting will start at 7.45pm at the Fulham Community Centre, off Phelps Court in Fulham (formerly known as the Reedbeds hall) with the presentation starting at 8.00pm. Following the meeting, tea coffee and cake will be served followed by a club business meeting.

Visitors are most welcome to come along – the meeting is open to everyone. We would love to see you down at the Amateur Radio Experimenters Group!

River Paddling Marathon 200: Practice Day This Saturday!

In preparation for the RPM200 there will be an opportunity to run through the practice for checkpoints at Murray Bridge this Saturday the 5th May.

Why are we getting together? We are honing our skill at spotting paddlers on the river for their back to back event, which in turn is a practice for the RPM. Getting the opportunity to practice scribing the paddlers numbers while they are on the far side of the river will help prepare us for tracking at checkpoints. This event will also help us understand what equipment we will need for the RPM. An afternoon sitting  beside the river isn’t a bad thing either, with a sausage or two sizzling on the BBQ.

What time: Arrive at the reserve at 12:00pm for the BBQ, with the first paddlers arriving around 1:00pm, through until around 4pm.

What to bring;

  • Lunch, offerings to the BBQ, drinks etc.
  • Hat, sun screen, jumper
  • Table and Chair
  • Optical amplification, ie binoculars
  • Pen & paper
  • Hand held radio

Where will you find us? Under the shelter at the Murray Bridge Foreshore Reserve;

Liaison on 439.025MHz FM Simplex.

If you are coming to participate, please let us know; kimhawtin@gmail.com