E0407

The E0407 is a directional wattmeter, made by IEMI in Bucharest and designed at the ICE research institute [1].

ICE’s laboratory for electronic instruments for measuring electrical quantities designed all the institute’s generations of oscilloscopes, voltmeters, multimeters, signal generators, frequency meters, logic analysers, RLC bridges and stabilised AC power supplies; they went into production at IEMI or in ICE’s own microproduction workshop, and equipped industrial laboratories and production lines as well as teaching and research laboratories [1]. In the 1970s and 1980s about half of the components of measuring instruments were imported; after 1980 about three quarters were Romanian [1].

ICE’s short-wave radio communications laboratory also lists a 1 kW through-line wattmeter, E 407, made at IEMI [2].

The E407 through-line wattmeter, for up to 1 kW at 1.5–30 MHz and used for tuning radio stations, was approved in 1984 and made at IEMI from 1986 [3].

It measures forward and reflected RF power and the standing wave ratio; it appears in IEMI’s 1988 range [4].

Annex III.2.8 describes it as compact and light enough to be portable, with ranges of 30, 100, 300 and 1000 W for forward and reflected power, a VSWR range of 1–50, an error of ±10% of full scale at 20 °C and N-type coaxial connectors; the instrument measured 95 × 200 × 155 mm and its directional coupler 95 × 85 × 140 mm [5].