SDR – Tecsun Radios Australia

For many shortwave listeners and amateur radio operators, the Tecsun Radios Australia SDR is a valuable tool for tuning into signals that may be impossible to hear from their own location. Whether you’re listening to international broadcasts or monitoring amateur radio activity, the online receiver opens up a world of listening opportunities.

What many users may not realise, however, is that the Tecsun SDR can also be used as a highly effective HF propagation monitoring tool thanks to its integrated International Beacon Project (IBP) extension.

What is the International Beacon Project?

The International Beacon Project (IBP) is a worldwide network of 18 continuously operating CW beacons managed by the Northern California DX Foundation (NCDXF). These stations are strategically located across the globe and transmit continuously on a rotating schedule across five amateur radio bands.

By monitoring which beacons can be

heard and at what signal strengths, radio operators can gain valuable insight into current propagation conditions between different parts of the world.

Accessing the IBP Scan on the Tecsun SDR

Using the feature is straightforward.

Simply select “IBP Scan” from the “Extensions” menu within the Tecsun SDR interface. The receiver will then display a series of thumbnail spectrum windows while automatically scanning all 18 beacon locations.

By observing the spectrum displays and listening to the CW transmissions, users can assess how well radio signals are travelling fro

m various regions of the world to the SDR receiving site.

Beacon Locations Around the World

The IBP network includes stations in:

New York City, USA (4U1UN)
Canada (VE8AT)
California, USA (W6WX)
Hawaii (KH6RS)
New Zealand (ZL6B)
Perth, Australia (VK6RBP)
Japan (JA2IGY)
Siberia (RR9O)
Hong Kong (VR2B)
Sri Lanka (4S7B)
South Africa (ZS6DN)
Kenya (5Z4B)
Israel (4X6TU)
Finland (OH2B)
Madeira (CS3B)
Argentina (LU4AA)
Peru (OA4B)
Venezuela (YV5B)

Because these beacons are spread across every inhabited continent, they provide an excellent snapshot of global HF conditions at any given time.

Beacon Frequencies

Each beacon transmits on five amateur bands:

At any given moment, five different beacons are transmitting simultaneously, one on each band.

Understanding the Transmission Sequence

Each beacon transmits for a 10-second cycle before the next beacon takes its turn.

During this sequence, transmission power is progressively reduced to help listeners judge path quality:

0 to 5.5 seconds: Callsign transmitted in CW at 22 WPM using 100 watts
5.5 to 6.5 seconds: Long dash at 10 watts
6.5 to 7.5 seconds: Long dash at 1 watt
7.5 to 8.5 seconds: Long dash at 100 milliwatts
8.5 to 9.5 seconds: Long dash at 10 milliwatts
9.5 to 10 seconds: Silent period before the sequence repeats

The lower-power dashes are particularly useful. If you can still hear the beacon at 100 milliwatts or even 10 milliwatts, it indicates an exceptionally strong propagation path between the beacon location and the receiving station.

What Can You Learn?

The beauty of the IBP system is that it transforms the SDR into a real-time propagation monitoring station.

For example:

Strong signals from North America may indicate favourable trans-Pacific conditions.
Improved reception from Europe can signal an opening on higher-frequency bands.
Weak or absent signals from traditionally reliable stations may suggest deteriorating propagation due to geomagnetic activity or changing solar conditions.
Comparisons between bands can reveal which frequencies are currently performing best for long-distance communication.

For amateur radio operators planning DX contacts, this information can be invaluable in choosing the optimal band and time to operate.

A Powerful Tool Hidden in Plain Sight

Many listeners use the Tecsun SDR solely as a remote receiver, but the built-in IBP Scan extension offers a fascinating way to study HF propagation in real time. By monitoring beacon activity from 18 locations around the world and observing how signal strengths vary across five amateur bands, users can develop a deeper understanding of the constantly changing nature of the ionosphere.

Whether you’re a seasoned DXer, a contest operator, or simply curious about how radio waves travel around the globe, the IBP Scan feature is well worth exploring.

Image: IBP thumbnail scan display showing beacon frequencies and callsigns as viewed within the Tecsun SDR interface. http://www.tecsunradios.com.au/store/tecsun-sw-radio-online/

Tecsun Radios Australia has set up a Software defined radio (receiver) in Araluen, a small rural community in NSW, Australia. It’s a quiet location for radio “noise”, far away from high density population and the accompanying RF noise generated.

You can listen to the Tecsun Radios Australia SDR here.

The SDR itself is called a “KiwiSDR” and is a commercially available unit, costing around $500. The Kiwi SDR compared to others has 2 advantages: (1) it allows the user to observe the entire shortwave spectrum in one screen, and (2) it can easily be connected to the internet to allow remote operation.

Other SDRs only receive a narrow portion of the radio spectrum, and require extra equipment to connect to the internet.

With the Kiwi SDR, it is easy to remotely identify that a signal exists from the “waterfall” display and then accurately tune and receive it.

The SDR is connected to two separate trapped HF vertical antennas. Each antenna is fed via common mode chokes ,one at the antenna end, and one at the equipment end of each cable run. These 2 antennas are then fed to an HF signal combiner. This provides some degree of antenna redundancy. The HF combiner feeds a 1:1 50 ohm transformer to isolate the KiwiSDR power supply ground from the antenna ground.

The antennas have been located as far away from man made noise sources as possible, and are fed with 75 ohm quad shield cable. Careful attention has also been paid to the grounding of the antenna.

Because the location is remote and in a bushfire affected area, mains power is supplemented by battery backup. The 5 volt power supply required by the KiwiSDR is a linear power supply that has a built in switching delay of 0.5 seconds, to ensure stable reset after power failure. We have been unable to surce a UPS with low RFI footprint for this application.

Connectivity to the www is achieved via a Skylink Ka band satellite link.

The Kiwi SDR can be used to receive AM, AM Narrow, USB, LSB, weatherfax, CW (Morse Code) and DRM signals.

The Tecsun Radios SDR ‘waterfall’

You can listen to the Tecsun Radios Australia SDR here.

Or, simply logon to the SDR (go to http://kiwisdr.com/public/ for a worldwide list), select an SDR located close to the transmission source you’d like to listen to, select the appropriate mode and the desired frequency.

Have you tuned into the Tecsun Radios SDR?
Tell us in the comments below where you’re tuning in from and what you listened to!

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Using the Tecsun SDR to Evaluate HF Propagation Around the World