Squarial

The Squarial (a portmanteau of the words square and aerial) was a satellite antenna used for reception of the now defunct British Satellite Broadcasting television service (BSB). The Squarial was a flat plate satellite antenna, built to be unobtrusive and unique. BSB was counting on the form factor of the antenna to clearly differentiate itself from its competitors at the time. At the time of development, satellite installations usually required a 90 cm dish in order to receive a clear signal from the transmitting satellite. The smaller antenna was BSB's unique selling point and was heavily advertised in order to attract customers to its service.

The Squarial was launched at a high-profile event in Marco Polo House, BSB's headquarters. The media were invited to a demonstration to see how much better MAC pictures could be than PAL. But MAC took a back seat when BSB unveiled the mock up Squarial, to replace the dish aerials usually needed for satellite reception. The Squarial was a surprise to everyone, including the four companies which had signed to manufacture the receivers which would have to work with the new aerial. The Squarial deal, with British company Fortel, had been struck only hours before the London event. BSB was itself surprised at the press reaction.

The media were apparently so excited by the new antenna that they failed to ask whether there was a working prototype, and there wasn't. All that existed at this point was a wood-and-plastic dummy. Believing that someone would be able to make the Squarial work as well as a much larger dish, BSB built a whole advertising campaign on the Squarial. STC in Paignton was the first company to make a British Squarial. These were a little bigger, 38 cm across, to provide adequate reception throughout the UK, and more expensive than a dish.^{[citation needed]} Due to production delays and limited availability of the STC squarial and to save face at launch, BSB sourced already available Squarials from Matsushita (now called Panasonic) in Japan which was producing them in quantity for the Japanese market. Industry rumours at the time of launch suggested that BSB was buying the squarials from Matsushita for several hundred pounds each and heavily subsidising the cost to the four manufacturers of DMAC receiver. The Matsushita squarial was of a slightly better quality construction compared to the STC design and was used by Ferguson, Philips and Tatung while ITT-Nokia supplied the STC squarial. However all offered the 30 cm traditional mini dish for a slightly lower price (several dish manufacturers were used including Lenson Heath and Channel Master).

The Squarial was withdrawn from sale in November 1990, a few days after the merger between BSB and Sky Television and it became obsolete in 1993, when the Marcopolo satellites, which the Squarial received, stopped broadcasting signals from BSkyB, which had carried the Sky channels over the D-Mac system for a period.

Unlike a normal satellite dish, which uses a parabolic reflector to focus the radio waves on a single feed horn antenna, the Squarial was a phased array antenna, a common design in which multiple small antennas work together to receive the waves. The Squarial consisted of a planar array of either 144 or 256 resonant cavity antennas spaced 0.9 wavelength apart, all embedded in plastic. Each antenna element was a tiny open-ended metal box in which the microwave downlink radio waves excited standing waves, with a wire probe projecting in which received the radio waves and conducted them to an integral low-noise block converter (LNB) amplifier. The feed network combined the radio currents from the separate elements with the correct phase so that radio waves from the desired direction would be in phase and add together, while radio waves from other directions would be out of phase and cancel.

Since the microwaves had to pass through the plastic surface to reach the antennas, special low-loss plastic was used. Three of these plastic sheets were stacked upon each other, padded with polystyrene layers to add rigidity to the unit. All this was engineered into a 38 cm white plastic body with the BSB logo at the bottom. The low-noise block converter mounted in the center, behind the layers, was a standard unit similar to those in other satellite dishes, which converts the frequencies from the satellite down to a lower frequency band around 800 MHz and transmits it through a coaxial cable into the building to the set-top box at the TV. It was manufactured by Matsushita and rated as a 10 GHz standard unit.

The Squarial's small size was possible thanks to the high power of the two Marcopolo DBS satellites, which simulcast the same channels on the same frequencies. The broadcast power was 59 dBW, with a 0.05 degree accuracy.

Manufacturers of the DMAC receivers used with the Squarial included, Ferguson, Phillips, Nokia and Tatung.