Ham Radio
Best Hobby A Young Man In The 1950's Could Have!
National Radio Company
The company was incorporated, in 1914, as the "National Toy Company",
but by 1916 had included household appliances in their product range.
This expansion led to the name change to the "National Company, Inc.".
By 1923 the product line included toys, food mixers, and radio
components. Radio components were to play an important part in the
company's growth in the mid 1920s as they moved in to the large scale
manufacture of capacitors. It was at this time that two engineers from
Harvard University, Fred H. Drake and Glen Browning, approached National
to manufacture components to their specifications for a radio receiver
of their own design. This relationship led to the production and sale of
the "National Regenaformer" kit for home construction of the
Browning-Drake design. The set was capable of tuning the standard AM
broadcast band only and could not achieve shortwave reception. By the
early 1930s National had established a reputation with the amateur radio
community based upon their line of regenerative receivers, including the
SW-3 and SW-5.
In 1935 National introduced their top-of-the-line HRO receiver. This
radio included two RF stages and a crystal filter. The distinctive dial
allowed KC (kHz) resetability and was a National trademark into the
1960s. With few changes other than to keep up with changing tube
technology, this same basic design survived for over 20 years.
In 1939, National became a key supplier to the US and Allied governments
when war broke out in Europe. Military representatives from branches
such as the Royal Navy visited National and ordered large numbers of
receivers, particularly HRO's. When the United States entered the war
some two years later, the word was, "Start building HROs; we'll tell you
when to stop." National began producing for the war effort, and the
number of employees went from approximately 200 to about 2500 during the
war. The war effort brought increased recognition and profits to
National and after the war, in the late 40s, National went public.
During the period in the 50s and 60s, National produced a wide range of
amateur radio equipment which was advertised extensively in the Amateur
Radio ARRL publication QST. Usually new equipment was first shown in
this publication in order to initiate marketing of a new item. The
company would mainly opt for the inside back cover which they believed
would gain prominence for their new wares. In addition, around Christmas
time each year National would produce tempting advertisements festooned
with holly leaves. In 1965, National introduced the solid state HRO 500,
which did not incorporate the famed HRO dial system, but instead relied
on a direct readout rather than a conversion scale or chart. At the
time, Popular Electronics magazine reviewed the HRO 500 as 'possibly the
best amateur receiver ever'. Today, many National radios are collected,
restored and operated by vintage amateur radio enthusiasts.
Through the 1970s and 1980s, National survived as a government
contractor and ceased development and production of civilian equipment.
However, by 1991, after continuing difficulties, the company ceased
trading.
About The NC303
These receivers were manufactured between 1958 - 1962. It is a seven band, ham-band only dual conversion receiver with a tunable HFO. The IFs are 2215 khz and 80 khz. For a filter, it uses an 80 khz L/C and a Q-multiplier. It has AM, CW, and Sideband mode selections. It has 15 tubes.
Tube lineup: 6BZ6 RF, 6BA7 mixer, 6AH6 HFO, 6BE6 mixer 2/ xco, 2 6BJ6 if, 6AL5 det/ANL, 6BE6 product detector/BFO, 6AL5 ssb-cw noise limiter, 12AT7 af1/meter amp, 12AX7 Q-multiplier, 6AQ5 af out, 4H4-C current regulator, 0B2 voltage regulator, 5Y3 rectifier. It produces 1 watt of audio into 8 ohms.
They made a wide variety of equipment through the years.
The NC-300 was extremely sensitive, and generally a real good radio for its time. It had a matching speaker, the NC-300TS, with a very cool thunderbolt "N." There was also a similar-looking case that held up to three accessory VHF convertors, for 6, 2, and (believe it or not) 220 MHz. These were switched in from the receiver, and had their own scales on the big dial. Electrically, all three downconverted to a 30 MHz top band on the main set, which served as a tunable IF.
The NC-300 was followed in 1958 by the NC-303 ($450), an improved version of the 300 which still shows up on a lot of all-time favorite lists right next to such legendary iron as the R-390, 75A-4, and SP-600! It had more filters, two different noise limiters, and a built-in Q-multiplier/ notch filter. The NC-303 lasted until the end of the boat anchor era in 1962.
I converted my receiver to solid state replacing all the tubes with semi-conductors. It worked even better than the original!