HF Antenna

4X4-INT Radio Amateur Research Station

4X4-INT Radio Amateur Research Station

4X4-INT Radio Amateur / Sky-wave Propagation experimental distributed receiver system is
one of the key demonstration tools at our RF Training center and serves as our “distributed receiver channel analyzer”.

This exciting research system originated from our need to find intuitive ways to teach and demonstrate mathematically complex subjects such as the physical channel’s attributes, Diversity, Beam-forming, MRC and MIMO. Comprising of our local HF / Low VHF reception site in Tel- Aviv, combined with channel samples taken from other remote SDR reception stations by Radio Amateurs around the world (also known as “reverse beacon” receivers), our system utilizes the ability to compare radio amateurs’ “beacon” signals, which are received at multiple sites in order to analyze key attributes of sky-wave propagation.

By comparing received signals which originated from the same Radio-Amateur’s beacon source, taken at multiple RX locations, the system can calculate the time-domain impulse response matrix of the distributed channel, allowing analysis of correlation between paths and much more. This allows our student to enjoy an amazing “playground” and to implement (by some signal processing to the received samples) MRC, MIMO and beam-form systems. The 4X4-INT site is also equipped with a state of the art radio amateur club station, for general purpose “ham radio” communications