Category Archives: Meetings

AREG April 17th Meeting – Software Defined Radio for Radio Amateurs

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Modern amateur radio is changing rapidly, and Software Defined Radio (SDR) is at the centre of that change. Many amateurs already own an SDR — or use one indirectly — but few have had the chance to understand how it actually works or why it feels so different from traditional radios.

This upcoming lecture will provide a plain‑language introduction to SDR, aimed specifically at amateur radio operators, not engineers or programmers.

Rather than focusing on mathematics or theory, the talk will explain SDR concepts using familiar radio ideas: receivers, mixers, filters, IF stages, and transmitters — and show how these functions are now being done in software instead of hardware.

Topics will include:

  • What “software defined” really means in a radio
  • Why SDRs can see so much spectrum at once
  • The role of analogue‑to‑digital converters and why bit‑depth matters
  • Why some SDRs are better at weak‑signal work than others
  • How modern SDRs replace IF strips with digital processing
  • What limits SDR transmit power and why filtering still matters
  • How SDRs are used by amateurs, researchers, and modern networks

The lecture will also touch on GNU Radio, the most widely used SDR software framework, explaining what it does and why it has become so important — without requiring any programming knowledge.

Whether you are:

  • Curious about SDR but unsure where to start
  • Using an SDR “black box” and want to understand what’s inside
  • Interested in digital modes, weak‑signal work, or experimentation
  • Wondering how modern radios differ from classic superhets

…this session is designed to demystify SDR and connect it back to the radio principles amateurs already know.

No prior SDR experience is required — just an interest in radio.

So when are where is this event? AREG meets at the Fulham Community Centre, off Phelps Court, in Fulham, Adelaide. Doors open at 7.00pm, Friday 17th April.

This month the meeting will begin with a short Special General Meeting to address a minor change to the group’s constitution, followed by the presentation which will likely start around 7.45pm.

For our regional members, the meeting will, as usual, also be interactively streamed via Zoom. If you are a regional amateur and are interested in finding out a little more about AREG, guest passes are available to our Zoom meetings on request. Please contact our secretary – via vk5arg@areg.org.au

 

AREG March Special Meeting – WSPRDaemon Wideband SDR Radio

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March General Meeting – Change of Time and Venue

Firstly, AREG wishes to advise that we will not be holding our normal March Friday night meeting on the 20th of March, as our meeting venue is not available this month due to it being used as a polling booth for this year’s state election. Instead, AREG is pleased to announce that we have a special guest presenter, Rob Robinett AI6VN, who will join us online from California via Zoom at a special meeting time of Saturday March 7th at 10AM Australian Central Summer Time.

WsprDaemon: A low cost, high performance, all band WSPR decoding system

Rob Robinett, AI6VN, will present an in-depth overview of WSPRDaemon, a low-cost, wideband software-defined radio (SDR) system designed for continuous monitoring of the MF and HF spectrum. WSPRDaemon uses the 16 bit / 128 Msps  RX-888 SDR receiver to digitize the entire 0-64 MHz spectrum which enables the simultaneous recording and reporting of 51 signals: all 11 of the WWV, WWVH and CHU time signals, all 18 of the 2200m – 6 meter WSPR bands, and all 22 of the FT4 and FT8 bands.

When the RX-888 is clocked by a GPS-Disciplined Oscillator, WSPRDaemon records WWV with sub-microhertz accuracy while WSPR ‘spots’ are reported with 0.01 Hz accuracy. That accuracy results in Doppler shift measurements like those shown in the above spectrogram, and from which radio scientists are gaining insights into previously poorly understood ionospheric dynamics, Traveling Ionospheric Disturbances (TIDs), and space-weather-driven propagation effects.

The system operates continuously 24/7 and automatically uploads WWV/CHU recordings to HamSCI servers where they are archived and made available for scientific research and collaborative analysis.

The presentation will cover system architecture, SDR hardware considerations, time and frequency accuracy requirements, software processing chains, and examples of real-world data products, including observations captured during geomagnetic storm events. Rob will also discuss how WSPRDaemon integrates into the HamSCI Personal Space Weather Station (PSWS) framework and how amateur radio operators can deploy stations that contribute meaningful, research-grade data.

This talk will be of particular interest to members involved in SDR, weak-signal modes, propagation research, frequency metrology, and advanced amateur experimentation.

 

AREG February Meeting: Operating on 241 GHz

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At our next general meeting, AREG is pleased to present a talk/demo by David VK5KK and Iain VK5ZD who will discuss their experiments on the 241 GHz microwave amateur band. This band is really the final fronteir in microwave amateur radio experimentation, given this is the highest frequency band allocated to the Amateur Service. David and Iain will take you through the gear they developed and also their efforts to set a VK distance record on this band.

To hear and see more, come along to the next general meeting of the Amateur Radio Experimenters Group, which will be held on Friday 20th February, starting at 7.30pm. AREG meets at the Fulham Community Centre, Phelps Court, Fulham. Doors open at 7.00pm. We hope to see you there!

AREG November Meeting – SA Repeater Network and the VK5RSB Repeater Rebuild

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The next meeting of the Amateur Radio Experimenters Group will be held this coming Friday, November 21st . The presentation this month is by Dean VK5HQ who will take people through the work that the AREG Repeater sub-group has undertaken at Summertown to rebuild it and prepare it to become the SA Repeater network hub repeater. He will also take you though the rest of the linked repeater network sites to give you an understanding of the reach and operation of the central SA network.The meeting was held at the Fulham Community Centre.

A copy of the presentation is available here

 

 

 

 

Next Meeting Friday Oct 17th – Digital Amateur Television

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The next meeting of the Amateur Radio Experimenters Group Inc will be held on Friday October 17th at 7.30pm. Doors will open at 7.00pm. The venue will be the Fulham Community Centre, Phelps Court, Fulham.

Introducing Digital Amateur Television

The topic this evening will be an introduction to 445 MHz (70 cm band) Digital Amateur Television, presented by Steve VK5SFA. Steve will present his journey to establishing an ATV transmission capability, including the various challenges encountered along the way.

Steve will also discuss how to get involved in receiving ATV on the 70cm band, and if you bring along your DVB-T set top box he will help you leave with it programmed ready to receive the local Adelaide ATV operators. The usual retailers are still selling the Laser STB-9000 for about $40.00 which will directly receive 70cm ATV if you want to get on board.

Update: a copy of the Youtube presentation is now available here:

Homework

Below is a list of terms used in DVB-t2 television broadcasting.  I will not be going into any great detail about how DVB-t2 actually works.  It is a mature technology and there is plenty of information on the Internet.
Feel free to conduct your own research if interested.
  • DVB-t (Digital Video Broadcasting – Terrestrial)
  • Coded Orthogonal Frequency Division Multiplexing (COFDM)
  • QPSK (Quadrature Phase Shift Keying) 
  • QAM (Quadrature Amplitude Modulation)
  • MER (Modulation Error Ratio)
  • FEC (Forward Error Correction)
  • Guard Interval
  • Carriers (2K & 8K)
  • PID (Packet Identifier)
  • LCN (Logical Channel Numbers)