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.
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.
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!