The Hammarlund Super Pro was an

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-made

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communications receiver Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether unintentional or failed transmissions are included and whether communication not only transmit ...

History

In March 1936, the

Hammarlund The Hammarlund Manufacturing Company was founded by Oscar Hammarlund in New York City, New York (state), New York, United States, in 1910. When the company was dissolved in 1973, it was among the United States' very oldest producers of radio equi ...

Manufacturing Company initiated the first of the famous "Super-Pro" line, the SP-10 receiver, followed in January 1937 by the SP-100. Their efforts to improve the design resulted in October 1939 with the SP-200 series, an 18-tube, single conversion superhet receiver. The SP-200 series Super-Pro receivers were manufactured through 1945, with thousands delivered to the military during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

; they saw wide use by the U.S. Signal Corps as the BC-779 and the BC-794. During World War II, government agencies like the

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used the 200 Series Super-Pro at their listening posts. Many were used at ground stations in

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to communicate with the

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and

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armadas that flew bombing missions over

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. According to a November 1940 QST Magazine ad, "The fact that 'Super-Pro' receivers are used extensively by the U.S. Signal Corps and many other governmental departments, speaks for itself." At the end of the war, the market was flooded with surplus Super-Pro receivers at bargain prices, which may be a reason many working examples of this model are still found today. From 1946 to 1948, Hammarlund produced the SP-400 Super Pro for the

amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ...

market. In 1947 the SP-600 Super-Pro receiver, which surpassed the SP-200 in performance, was introduced. The SP-600 series were widely used throughout the world for military, laboratory and commercial application.http://www.hammarlund.info/histpage.html''The Hammarlund Historian''

Specifications

SP-200

Various models of the SP-200 series cover 0.1–40

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...

in 5 bands. The radio and cabinet weigh 73 pounds (33 kg) while the separate power supply adds another 57 to 61 pounds. The Super-Pro was first offered in two basic models, with and without a crystal filter.

SP-400

The SP-400 Super Pros were very similar to the SP-200's with the differences being mainly cosmetic. They were only made from 1946 to 1948 and had outboard power supplies like the earlier Super Pros. There were two of them, the SP-400-X which tuned from .54 to 30 MHz, and the SP-400-SX which tuned from 1.25 to 40 MHz.

SP-600

The SP-600 Super Pro covered the frequency range of 540

kHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base uni ...

to 54

.http://www.dxing.com/rx/sp400x.htm DXing.com SP-600 * SP-600-J omitted optional crystal control of selected frequencies. * SP-600-JLX-2,15 and 23 covered .1–.4, 1.35–29.7 MHz. * SP-600-JX-17, 30 were for

diversity reception In telecommunications, a diversity scheme refers to a method for improving the reliability of a message signal by using two or more communication channels with different characteristics. Diversity is mainly used in radio communication and is a c ...

use. * SP-600-VLF-31, 38 was limited to 10–540 kHz. * SP-600-JX-21A had 22 tubes and featured SSB reception. * SP-600-JLX-27 covered 0.2–0.4 and 0.54–29.7 MHz. * SP-600-JX-28 was R-620. * SP-600-JX-6 was R-274B. * SP-600-JX-12 was R-274A. * SP-600-JX-29 was produced for the

CIA The Central Intelligence Agency (CIA; ) is a civilian foreign intelligence service of the federal government of the United States tasked with advancing national security through collecting and analyzing intelligence from around the world and ...

. * SP-600-JX-39 was produced for the FAA.

References

{{Reflist

General references

*War Department Technical Manual TM11-866, 31 August 1943 ''Radio Receivers BC-779-B, BC-794-B, and BC-1004-C and Power Supply Units RA-74-C, RA-84-B, and RA-94-A'' *Instruction Book for "Super-Pro" Radio Receiver (100-400 kc and 2.5-20 Mc), overprinted ''Radio Receiver BC-779-A and Power Supply Unit RA-84-A'', Undated, ''Published by Authority of The Chief Signal Officer, Order No. 21109'' *''Series 200 Super-Pro by Hammarlund'', undated. *''Communications Receivers, The Vacuum Tube Era 1932-1981'', 3rd Edition, by Raymond S. Moore

External links

''The incredible pre-war Super Pro'', Western Historic Radio Museum
Amateur radio receivers Military radio systems World War II American electronics Equipment of the United States Air Force