R-390A
Encyclopedia
The R-390A /URR
is a general coverage HF
radio
communications receiver
designed by Collins Radio Company for the US military.
shortwave
radio receiver was the result of a project undertaken by the U. S. Army Signal Corps in 1954 to replace the existing R-390 receiver then in use. The R-390 had done its job so well that the Corps decided continued use of this type of receiver necessitated an improved, reduced-cost version.
Originally built by Collins Radio Company in Cedar Rapids, Iowa
, the R-390A was designed by two teams. The mechanical team was led by Fred Johnson while the electronics team was overseen by Collins' Ernie Pappenfus, K6EZ. Besides Collins Radio, other sub-contractors (including Motorola
, Stewart Warner, Capehart, Teledyne
, and others) built R-390As until the last one rolled off the assembly line in 1984. Banks of these radios served the country in all branches
of the US military. Additionally, they found service with the CIA and NSA to monitor communications from behind the Iron Curtain
. Although one citation states that during the Cold War
years, the R-390A was so valued it was classified top secret, a security measure which remained in force until the mid-1960s, there are many references to the R390A in the open literature during this period; a picture of the receiver appeared in the May 1959 issue of the amateur radio magazine QST.
Total production of the R-390A (as determined by the high serial numbers noted) is over 55,000 units. Initial production started in 1955 and ran through approximately 1970, and then was restarted in 1984 by Fowler Industries for Avondale Shipyards. Manufacturers and their approximate production numbers are:
Companies which made spare modules, but not whole sets were Communications Systems Corp., Clavier Corp. and Hacking Labs.
, code
, and frequency shift keying signals. Its tuning range is from 500 kilohertz to 32 megahertz, in 32 one-megahertz bands. The circuit is the superheterodyne type, double conversion above 8 MHz, below which triple conversion is used. It employs 26 vacuum tube
s, a larger than normal count for most general-coverage receivers. The receiver weighs 85 pounds and can be operated on 120 volt or 240 volt supplies. It fits neatly into a 10.5 inch-tall standard 19 inch equipment rack.
Tuning of the R-390A's radio frequency and intermediate frequency
front end is synchronized by means of an ingenious mechanical system of racks, gears, and cams. When the front panel tuning controls are rotated, this system raises and lowers ferrite
slugs in and out of the receiver's tuning coils. This ensures that all front-end circuits are tracked, meaning all circuits are tuned to the correct frequency to maintain excellent selectivity and sensitivity. The receiver's construction is modular for easy servicing. Each major area of the receiver is contained in easily removable subassemblies, and these can be repaired or replaced as needs be. Though the R-390A is mechanically and electrically complex, alignment and servicing were designed to follow simplified procedures published by the Signal Corps.
. There are reports, possibly apocryphal, that R-390A receivers are still in use aboard U. S. Navy submarines since the receiver can withstand the strong radio frequency
fields found aboard ship.
Many of the R-390As that exist today are in the hands of vintage amateur radio
collectors and amateur radio
operators who contend that few modern solid state communications receivers can equal its performance. There is a wealth of information, both printed and electronic, devoted to R-390A restoration and maintenance, as the R-390A is widely considered an example of the best of vacuum tube
technology.
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...
is a general coverage HF
High frequency
High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...
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...
designed by Collins Radio Company for the US military.
History
The R-390A militaryMilitary
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
shortwave
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
radio receiver was the result of a project undertaken by the U. S. Army Signal Corps in 1954 to replace the existing R-390 receiver then in use. The R-390 had done its job so well that the Corps decided continued use of this type of receiver necessitated an improved, reduced-cost version.
Originally built by Collins Radio Company in Cedar Rapids, Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, the R-390A was designed by two teams. The mechanical team was led by Fred Johnson while the electronics team was overseen by Collins' Ernie Pappenfus, K6EZ. Besides Collins Radio, other sub-contractors (including Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
, Stewart Warner, Capehart, Teledyne
Teledyne
Teledyne Technologies Incorporated is an industrial conglomerate primarily based in the United States but with global operations. It was founded in 1960, as Teledyne, Inc., by Henry Singleton and George Kozmetsky....
, and others) built R-390As until the last one rolled off the assembly line in 1984. Banks of these radios served the country in all branches
Military of the United States
The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...
of the US military. Additionally, they found service with the CIA and NSA to monitor communications from behind the Iron Curtain
Iron Curtain
The concept of the Iron Curtain symbolized the ideological fighting and physical boundary dividing Europe into two separate areas from the end of World War II in 1945 until the end of the Cold War in 1989...
. Although one citation states that during the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
years, the R-390A was so valued it was classified top secret, a security measure which remained in force until the mid-1960s, there are many references to the R390A in the open literature during this period; a picture of the receiver appeared in the May 1959 issue of the amateur radio magazine QST.
Total production of the R-390A (as determined by the high serial numbers noted) is over 55,000 units. Initial production started in 1955 and ran through approximately 1970, and then was restarted in 1984 by Fowler Industries for Avondale Shipyards. Manufacturers and their approximate production numbers are:
- Collins Radio Company 6,363
- Electronic Assistance Corp 15,338 (includes Dittmore Freimuth marked radios)
- Capehart 4,242
- Motorola 14,873
- Stewart Warner 6,631
- Amelco/Teledyne/Imperial 7,958 (these companies were related through acquisitions)
- Fowler Industries 5
Companies which made spare modules, but not whole sets were Communications Systems Corp., Clavier Corp. and Hacking Labs.
Design
The R-390A is a general coverage radio receiver capable of receiving amplitude modulatedAmplitude modulation
Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...
, code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
, and frequency shift keying signals. Its tuning range is from 500 kilohertz to 32 megahertz, in 32 one-megahertz bands. The circuit is the superheterodyne type, double conversion above 8 MHz, below which triple conversion is used. It employs 26 vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s, a larger than normal count for most general-coverage receivers. The receiver weighs 85 pounds and can be operated on 120 volt or 240 volt supplies. It fits neatly into a 10.5 inch-tall standard 19 inch equipment rack.
Tuning of the R-390A's radio frequency and intermediate frequency
Intermediate frequency
In communications and electronic engineering, an intermediate frequency is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called...
front end is synchronized by means of an ingenious mechanical system of racks, gears, and cams. When the front panel tuning controls are rotated, this system raises and lowers ferrite
Ferrite (magnet)
Ferrites are chemical compounds consisting of ceramic materials with iron oxide as their principal component. Many of them are magnetic materials and they are used to make permanent magnets, ferrite cores for transformers, and in various other applications.Many ferrites are spinels with the...
slugs in and out of the receiver's tuning coils. This ensures that all front-end circuits are tracked, meaning all circuits are tuned to the correct frequency to maintain excellent selectivity and sensitivity. The receiver's construction is modular for easy servicing. Each major area of the receiver is contained in easily removable subassemblies, and these can be repaired or replaced as needs be. Though the R-390A is mechanically and electrically complex, alignment and servicing were designed to follow simplified procedures published by the Signal Corps.
Use
The R-390A was deployed to most branches of the US military and remained in general use through the 1980s. The last major update to its documentation was in 1984. As the military procured newer receivers, many R-390As were released to surplus while others were destroyed. Some receivers were retained by the services, however, when they found that the R-390A's vacuum tube circuitry could easily survive an electromagnetic pulseElectromagnetic pulse
An electromagnetic pulse is a burst of electromagnetic radiation. The abrupt pulse of electromagnetic radiation usually results from certain types of high energy explosions, especially a nuclear explosion, or from a suddenly fluctuating magnetic field...
. There are reports, possibly apocryphal, that R-390A receivers are still in use aboard U. S. Navy submarines since the receiver can withstand the strong radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
fields found aboard ship.
Many of the R-390As that exist today are in the hands of vintage amateur radio
Vintage amateur radio
Vintage amateur radio is a subset of the amateur radio hobby, considered a form of nostalgia much like antique car collecting, where enthusiasts collect, restore, preserve, build, and operate amateur radio equipment from bygone years, most notably those using vacuum tube technology.Popular modes of...
collectors and 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...
operators who contend that few modern solid state communications receivers can equal its performance. There is a wealth of information, both printed and electronic, devoted to R-390A restoration and maintenance, as the R-390A is widely considered an example of the best of vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
technology.
See also
- ART 13 transmitter
- ARC-5ARC-5The AN/ARC-5 Command Radio Set is a series of radio receivers, transmitters, and accessories used to provide two-way Morse code and AM radiotelephone communication for U.S. Navy aircraft during World War II and the years following. It was an improvement of the Navy's ARA/ATA command set. Similar...
- BC-348BC-348The BC-348 is a compact American-made communications receiver, which was mass-produced during World War II for the U.S. Army Air Force. Under the Joint Army-Navy nomenclature system, the receiver system became known as the AN/ARR-11. -History:...
- BC-654BC-654The SCR-284 was a World War II era combination transmitter and receiver used in vehicles or fixed ground stations.- History :The Crosley Corporation of Cincinnati, Ohio manufactured the Signal Corps Radio set SCR-284 that consisted of the BC-654 and associated support equipment.The BC-654 first saw...
- Collins Radio
- Hammarlund super proHammarlund Super ProThe Hammarlund Super Pro was an American made radio communications receiver.- History :In March 1936, the Hammarlund Manufacturing Company initiated the first of the famous “Super-Pro” line, the SP-10 receiver, followed in January 1937 by the SP-100...
- National HRONational HROThe original National HRO was a 9-tube shortwave general coverage communications receiver manufactured by the National Radio Company of Malden, Massachusetts, USA.-History:...
- Vintage amateur radioVintage amateur radioVintage amateur radio is a subset of the amateur radio hobby, considered a form of nostalgia much like antique car collecting, where enthusiasts collect, restore, preserve, build, and operate amateur radio equipment from bygone years, most notably those using vacuum tube technology.Popular modes of...
- Sherwood Engineering's HF Receiver Performance Specs.
General references
- Rippel, Chuck. R-390A History and R-390A Overview. The R-390A/URR Archive on the Web. (Nov 15, 2010)
- Couillard, L. W, Cost Reduction Program for Radio Receivers R-390. Cedar Rapids, Iowa: Collins Radio Company, 1952
- United States Department of the Army, Technical Manual TM-11-5820-358-35: Radio Receiver R-390A/URR. Washington, DC: Government Printing Office, 1961.