A radar of particular use at close range has a CRT (3) that is scanned in a spiral fashion by applying phase quadrature sinusoidal signals to resonant deflection coils (31 and 32). A digitizer (43) converts the radar return signals to multi-bit signals which are supplied to a memory (50) with signals for alternate pixels stored in different halves of the memory (51 and 52). The apparatus reads out signals from one half of the memory (51) during one scan and reads out signals from the other half (52) of the memory (50) during the next scan so that they are interleaved with the pixels on the display brightened by the first scan.