Circa 1950s Czech RZ-301 portable radio direction finder, codenamed 'POSPISIL,' designed to locate clandestine radio transmissions. With this unit covertly concealed in a leather briefcase, a member of the secret police could sweep for secret radio transmissions. The finder is comprised of a black box with large 'window' antenna, measuring an overall 3.5″ x 12″ x 15″, with an identification plate on the front reading: "RZ301, Serie D, c.05189." The control panel has a tuning scale, tuning knob, CW/AM switch, on/off switch, and headphones output. In the bottom is a slot for one of four frequency cartridges, corresponding to different ranges. All four plug-in units are included: "I. 1.3 - 2.8 MHz," "II. 2.5 - 5.4 MHz," "III. 5.3 - 10 MHz," and "IV. 9.5 - 20.3 MHz." In very good to fine condition.
