The National Radio Company, along with Hallicrafters, and Hammarlund, was once one of the “big three” American manufacturers of shortwave receivers and communications equipment.

The company began in 1914 as the National Toy Company, in Cambridge, Massachusetts. By 1916, it branched out into household and mechanical goods, and shortened its name to the National Company. In the early 1920s the company was approached by the Boston representative of Cardwell Capacitors, who was having trouble fulfilling capacitor orders. National agreed to supply him with capacitors and thus entered the radio business.

National broadened its involvement in radio when it agreed, in 1924, to manufacture components for the Browning-Drake kit receiver. National supplied the coils, marketed as the “National Regenaformers”, and also the capacitors and knobs. One component, the tuning dial, was of sufficient quality to be sold on its own. This was the National “Velvet Vernier” dial, which would become one of the company’s staple products.

A turning point in National’s history was in 1928 when James Millen joined the company as chief engineer and general manager. Millen was a mechanical and electrical engineer, and his influence would soon become evident in the company’s products. Millen was also a talented writer, and his articles on technical developments at National were found in many of the popular radio journals of the time, particularly in QST (the American Radio Relay League’s journal).

National, under Millen’s guidance, began to test the receiver market. One of the first products that the company produced was the famous “Thrill Box” series of receivers. These inexpensive receivers (of which the model SW-3 is the best known) were reliable performers. They were sold in the late 1920s and early 1930s, and helped bolster the company’s reputation.

In 1932, National (now known as the National Radio Company) introduced the first of a long line of classic receivers. This was the model AGS, for Aircraft Ground Station use, probably the most advanced communications receiver available at that time. It was developed in conjunction with the U. S. Department of Commerce Airways Division and required nine vacuum tubes. The AGS was made available for commercial sale, but few Depression-era ham radio operators could afford it.

Accordingly, National decided to offer a lower-cost version of the AGS. This was the model FB-7, released in 1933. It featured a set of plug-in coils for easy band changing and sold for a more reasonable $26. The FB-7 was a small regenerative circuit type receiver, capable of decent performance.


With the success of the FB-7, National discontinued its earlier products and moved full-time into receiver design and manufacture. Near the end of 1933, the company began work on what would become its most famous series of receivers. Earlier, James Lamb, a well-known radio engineer, had authored an article in QST entitled “What’s Wrong With Our Present Receivers”, in which he discussed current design problems and possible solutions. Millen put many of Lamb's ideas into practice with the design of the HRO series of receivers, which were based on the AGS. The first model to appear was the original HRO, introduced in March 1935. The receiver was an electrical and mechanical marvel; among its features were:

  • The PW dial, a large dial with cutout windows. As the operator rotated the dial, the numbers inside the dial ascended or descended, and partially indicated the frequency to which the receiver was tuned.
  • A tight differential gear drive, which made for precise tuning with little or no backlash.
  • Well-designed plug-in coils and ganged tuning capacitors, each in their own compartments. This reduced interaction between the components and assured a stable receiver.

National, and Millen, followed the successful HRO series with the NC-100 and NC-101 series of receivers. The NC-100 was a general coverage receiver, and the 101 covered only the existing Amateur Radio bands. Instead of plug-in coils, these receivers featured a gear driven coil catacomb. As the operator selected the required band, the catacomb moved the corresponding tuning coils into position. This system avoided the leakage and cross-coupling inherent in normal mechanical bandswitch operation. National continued to use the coil catacomb in its receivers until 1947.

In early 1939, the National Radio Company became a publicly traded company. There was internal disagreement over this move and, as a result, James Millen decided to leave the company. He went on to form the James Millen Manufacturing Company, and built a successful business manufacturing precision radio parts. With Millen went much of National’s innovative spirit; the company would continue to design and produce receivers (sometimes of varying quality), but would not again be an industry leader.

During World War II National, like most major receiver manufacturers, converted to wartime production. The company supplied the HRO and NC-100 receivers to all the armed forces. As time went on, these receivers would go through many variations as the military’s requirements and specifications changed.


National spent the 1950s and 1960s fulfilling government and military contracts. The company continued to introduce new receiver models, but these models were mostly improvements on their pre-war designs. Notable during this period was the NC-183D receiver, a band switching receiver that was an engineering departure for National, but rather conventional by industry standards. However, it was very successful and a stable performer. Many NC-183Ds are still in service, and the receiver is highly prized by collectors.

The company made an attempt in 1955 to regain primacy in the receiver field. National had been hinting, in radio journals, of a new “dream receiver” that would shortly be available. This was the model NC-300 amateur band only receiver, a huge box designed to appeal to operators wanting a receiver that was, as advertisements put it, “massive in the modern manner”. It was followed in 1958 by the improved NC-303. Both receivers were excellent performers, but they met with only moderate success. The public’s idea of a modern receiver had shifted to smaller, more compact designs.

Nonetheless, National persevered with its design philosophy. The company brought out a final receiver in the NC series, the model NC-400. This was a general coverage receiver, introduced in 1959. It featured sleek styling, double conversion in the radio-frequency section, and crisp audio response. The NC-400 is rarely seen today; a mystique has developed around this receiver, and it commands a high price when one does surface.

Around this time National, again like other receiver manufacturers such as Hallicrafters, decided to test the consumer television and stereo markets. The company met with varying degrees of success, though, and soon abandoned the consumer market.


As the communications industry moved toward solid state electronics, National wasted no time adapting. Recapturing some of its earlier innovative spirit, the company introduced a completely transistor based receiver in 1964, the model HRO-500. It was among the first communications receivers to implement full frequency synthesis, and featured the PW dial of the original HRO series, albeit modernized. The HRO-500 was a success, but the design was not without flaws. The transistors were socketed, and this led to numerous service problems. Nevertheless, the HRO-500 was ahead of its time and is today another highly collectible receiver. It was followed in 1968 by the model HRO-600, an expensive mainframe-based receiver that was intended for professional use. The HRO-600 is rarely seen today.

By the end of the 1960s, the National Radio Company had become a shell of its former self. It had underbid on a few military projects, such as the military WRR-2 receiver (a huge receiver containing sixty-four vacuum tubes, intended to replace the Collins R-390A). These projects ultimately cost more to produce than the original bids had specified, and the company was forced to reorganize under Chapter 13 bankruptcy rules.

National struggled on, existing mainly on its remaining government contracts, until 1992. That year, the company was forced, by the Internal Revenue Service, to liquidate its remaining assets and cease business. Since that time, there has been no mention of a revived National Radio Company.


Orr, William I., W6SAI. “The Golden Years of Radio: The National AGS Receiver”. CQ Magazine, November 1975: pages 25-29.
Moore, Raymond. Communications Receivers, Fourth Edition: La Belle, Florida, RSM Communications, 1997
Osterman, Fred. Shortwave Receivers Past and Present: Reynoldsburg, Ohio, Universal Radio Research, 1998

Log in or register to write something here or to contact authors.