A SART radar signature typically appears as which pattern?

• A. A single bright dot
• B. A ring of dashes
• C. 12 dots, then 12 arcs, then 12 concentric circles
• D. A flashing square

Answer: (C)

A SART signature is a distinctive, time-based radar response that shows up as a recognizable pattern on the interrogating radar screen. When the SAR transponder is activated by the radar’s sweep, it replies with a burst of pulsed energy that the radar displays in a way that traces out specific shapes as the antenna rotates.

First you see a line of about a dozen bright dots. These dots come from the SART’s pulsed replies aligning with the rotating radar beam, so you get discrete points as the beam crosses the beacon area. As the sweep continues, these replies also trace out curved segments, appearing as about a dozen arcs. Finally, the continued transmissions produce several rings around the beacon, seen as concentric circles, again in a count around a dozen. Altogether, the pattern of 12 dots, then 12 arcs, then 12 concentric circles is the characteristic SART signature and is used to identify and locate a SART on the radar display.

This isn’t a single dot, a ring of dashes, or a flashing square, because those shapes don’t reflect the timed, rotating-beam pulsed response that a SART emits when interrogated.