The former „National Toy Company“ renamed to become National Company Inc. in 1916, produced radio components for the „Browning - Drake broadcast receiver kit“ and „Velvet vernier“ dial drives from 1924.
Under the direction of James Millen, National began to develop increasingly powerful shortwave receivers, the „Thrill Box“ from about 1927 was followed by the SW-5 and SW-3 receivers. In 1932, National launched the AGS, the „aeronautical ground station“, the most powerful communications receiver to date, already a design with interchangeable coils and a dial with fine tuning arrangement. It was followed in autumn/winter 1934 by the famous receiver HRO, developed with the support of Herbert Hoover. This receiver was equally successful as a communications receiver among radio amateurs as in commercial and military use.
It's concept with plug-in coil sets in slide-in units and the PW dial, a round tuning dial with gears and small windows arranged in a star shape in the tuning knob showing numbers, was retained throughout the war years.
It was not until the successor model to the NC-100, the NC-100 in the A version, that a „direct readout“ dial was fitted; when changing the wave band, the coil sets no longer had to be reinserted but were brought into the correct position my means of a movable „coil catacomb“ in the bottom of the set. This receiver was used in various military variants. After the Second World War, in addition to commercial and military shortwave receivers, National also developed amateur radio receivers in different price categories. The company missed to keep up with the development towards a compact and lighter generation of equipment.
With its HRO-500, the first communication receiver built in semiconductor technology with synthesiser technology, National brought another technical innovation to the market in the year 1964. After the company went bankrupt in 1969, National continued to produce military equipment for a few years under government contracts, but was unable to recover. In 1991, the last company inventory was in an auction sale.
|AGS||1933||Single conversion||1.5 - 20 MHz, additional coils for the ham bands||AM, CW/SSB (BFO)|
|HRO||1934/38||Single conversion||1.7 - 30 MHz, with additional coils 50 kHz - 30 MHz||AM, CW/SSB (BFO)|
|NC-100XA||1938||Single conversion||0.5 - 30 MHz||AM, CW/SSB (BFO)|
|HRO-7||1947||Single conversion||1.7 - 30 MHz, with additional coils 50 kHz - 30 MHz||AM, CW/SSB (BFO)|
|HRO-50||1950||Single conversion||50 kHz - 30 MHz||AM, SSB (BFO)|
|HRO-500||1964||Single conversion||5 kHz - 30 MHz||AM, USB/LSB|