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RF Shorts – Feb. 16, 2012

A Huge, Historic AM Antenna Celebrates its 75th Anniversary
Check out this video on the Australian Broadcasting Company's web site Celebrating World Radio Day with a trip around the world. The 201 meter tall 3WV mast in Western Victoria has a 19 meter wide capacitive top hat. Its 594 kHz signal has been heard as far as Canada, Japan and South Africa. Horsham resident James Heard commented, "It really meant a lot to us. It must've been a big undertaking in 1936 to build it because cranes and things that are about today weren't even heard of."

Testing MIMO Radios
Radios with conventional antennas can be easily tested in anechoic chambers, but how do you test radios that use MIMO (multiple-input, multiple-output) technology that's now becoming common in 802.11n Wi-Fi and LTE radios? Test and Measurement World has a good overview in the article Test MIMO Wi-Fi and LTE radios over the air – OTA testing can simulate conditions such as reflections and fading in a controlled environment by Fanny Mlinarsky.

The Advanced Communications Testbed
JPL describes a communications package with all manner of interesting equipment in its release about the Advanced Communications Testbed for Space Station. The release says, "The testbed will be the first space hardware to provide an experimental laboratory to demonstrate many new capabilities, including communications, networking and navigation techniques that utilize Software Defined Radio technology. The SCaN Testbed includes three such radio devices, each with different capabilities. Two Software Defined Radios were developed under cooperative agreements with General Dynamics, West Falls Church, Va., and Harris Corp., Melbourne, Fla., and the third was developed by NASA's Jet Propulsion Laboratory Pasadena, Calif. JPL also provided the five-antenna system on the exterior of the testbed, which will be used to communicate with NASA's orbiting communications relay satellites and NASA ground stations across the United States."

More information and pictures are available on the web page Communications, Navigation and Networking re-Configurable Testbed (CoNNeCT/SCAN Testbed).

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.