Poor Man's Radar

An airport's instrument-landing radar is a gadget-lover's dream. Outside, it blossoms with dials, scopes and switches, and its insides are stuffed with wires and vacuum tubes that look like spaghetti sprinkled with caviar. It is such an expensive gadget that only big airports can get it. Last week Britain's Ekco Co. was telling about its "poor man's radar," designed for the pocketbook of the small-field manager.

Four years ago Manager Bernard Collins, of Britain's Southend Airport near the mouth of the Thames, was having a drink with Tony Martin, chief radar engineer of Ekco. "If only you boffins,"-said Collins, "would give us a cheap way of locating an aircraft, then we'd be quids in." Martin said he would "look around in the factory junkshop."

He found nothing suitable in the junk-shop, but Collins' suggestion set him thinking. The trouble with radar, he decided, is a too-prosperous infancy. It grew up in wartime, when the military had unlimited money to lavish on it. Each improvement was achieved by adding complication. So. radar bypassed the "primitive" early stages of its evolution.

Martin started to backtrack, trying to design the simple radar that might have been developed in the early days if military money had not been so plentiful. He consulted continually with Collins (usually in a pub), and whenever he suggested adding another tube, Collins complained that he didn't want a cheaper radar, he wanted a really cheap one that would land planes effectively in the fog.

Held rigidly down to the primitive level, Martin's "Approach Aid" (on the market last week) has only 50 tubes and costs less than -L-4,000 ($11.200), while a standard airport radar has something like 1,200 tubes and costs about -L-50,000. The poor man's radar has no spinning surveillance antenna as does conventional Ground Control Approach Radar and so does not give a continuous radar-eye view of the air around the airport. Instead it shoots out only a single narrow beam of radar pulses. Guided by a direction finder, the operator swings the beam with a pair of "handle bars" until it picks up an approaching plane. A "blip" on the radar's scope tells him that he has found it. Then, keeping the plane in the scope, he "talks" it down just as operators do with more complicated radars.

The Ekco Approach Aid is now in legal operation at Southend Airport, where it was used successfully during the record fog that plagued Britain early this month. The R.A.F. has ordered 25 sets, and the U.S. armed services are interested.

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