Hammarlund Super Pro - AbsoluteAstronomy.com

The Hammarlund Super Pro was an American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

made radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

communications receiver

Communications receiver

A communications receiver is a type of radio receiver used as a component of a radio communication link.-Features:Commercial communications receivers are characterised by high stability and reliability of performance, and are generally adapted for remote control and monitoring...

History

In March 1936, the Hammarlund

Hammarlund

The Hammarlund Manufacturing Company, founded by Oscar Hammarlund in New York City, New York, USA in 1910, initially designed and produced short wave radio equipment.-History:...

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. While designed as a communications receiver, Hammarlund also promoted a home version in a console cabinet during the mid-thirties The SP-200 series Super-Pro receivers were manufactured through 1945, with many thousand delivered to the military during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

and saw wide use by the U.S. Signal Corps. The Military designation

Joint Electronics Type Designation System

The Joint Electronics Type Designation System , which was previously known as the Joint Army-Navy Nomenclature System and the Joint Communications-Electronics Nomenclature System, is a method developed by the U.S. War Department during World War II for assigning an unclassified designator to...

s for the receiver were BC-779-A/B (the most common), BC-794-B, BC-1004-C as well as R-129/U and R-270/FFR. During World War II, government agencies like the FBI used the 200 Series Super-Pro at their listening posts. Many were used at ground stations in England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

to communicate with the Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

and U.S. Air Force armadas that flew bombing missions over Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. According to a November 1940 QST Magazine

QST

QST is a magazine for amateur radio enthusiasts, published by the American Radio Relay League . It is a membership journal that is included in membership with the ARRL. The publisher claims that circulation of QST in the United States is higher than all amateur radio-related publications in the...

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

Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...

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.

SP-200

Various models of the SP-200 series cover 0.1 - 40 MHz 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, one with, and one without, a crystal filter. All the models are 18-tube (16 in the receiver, 2 in the separate power supply), single conversion superhets with 2 RF stages and 3 IF stages operating at 465 kHz. In addition to a 5 position single-crystal filter with variable phasing, the IF selectivity is continuously variable between 3 and 16 kHz. The radios are equipped with full bandspread on all except the 0.1 to 0.4 MHz bands, variable BFO, diode noise limiter, and 14 watts of audio output power. Claimed sensitivity is 1.0 to 1.7 microvolts on the LF and HF ranges. The main dial calibration is 1/2 of 1 percent of the highest frequency on each band. Total power consumption is about 180 watts. Initially, two versions were manufactured. One tuned from the low end of the broadcast band to 20 MHz, and the other started at 1250 kHz and went up to 40 MHz.

The three basic models (there were additional variants and modifications) were:

SP-210-X or BC-1004-C (0.54 - 20 MHz)
SP-210-SX or BC-794-B (1.25 - 40 MHz)
SP-210-LX or BC-779-B (0.1-0.4 and 2.5-20 MHz)

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 -40 MHz.

SP-600

The SP-600 Super Pro covered the frequency range of 540 kHz to 54 MHz with a 0-100 calibrated mechanical band spread. The receiver had provisions for optional crystal control of six selected frequencies. A number of variants were produced.

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 use.
SP-600-VLF-31, 38 was limited to 10–540 kHz.
SP-600-JX-21A had 22 tubes and featured SSB
Single-sideband modulation
Single-sideband modulation or Single-sideband suppressed-carrier is a refinement of amplitude modulation that more efficiently uses electrical power and bandwidth....

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

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