Neither a single nation nor a single person can say that the discovery and development of radar technology was his (or its) own invention. One must see the knowledge about “Radar” than an accumulation of many developments and improvements, in which any scientists from several nations took part in parallel. In the past, there are nevertheless some milestones, with the discovery of important basic knowledge and important inventions:

1865 The Scottish physicist James Clerk Maxwell presents his “Theory of the Electromagnetic Field” (description of the electromagnetic waves and their propagation) He demonstrated that electric and magnetic fields travel through space in the form of waves, and at the constant speed of light.

1886 The German physicist Heinrich Rudolf Hertz discovered electromagnetic waves, thus demonstrating the Maxwell theory.

1897 The Italian inventor Guglielmo Marconi achieved the first long distance transmission of electromagnetic waves. In his first experiments he used a wire to a wooden pole. In Italian a tent pole is known as l’antenna centrale, and the pole with a wire alongside it used as an aerial was simply called l’antenna. Today Marconi is known as pioneer of radio communication.

1900 Nicola Tesla suggested that the reflection of electromagnetic waves could be used for detecting of moving metallic objects.

1904 The German engineer Christian Hülsmeyer invents the “telemobiloscope” for a traffic monitoring on the water in poor visibility. This is the first practical radar test. Hülsmeyer apply his invention for a patent in Germany, France and the United Kingdom.

1921 The invention of the Magnetron as an efficient transmitting tube by the US-american physicist Albert Wallace Hull.

1922 The American electrical engineers Albert H. Taylor and Leo C. Young of the Naval Research Laboratory (USA) locate a wooden ship for the first time.

1930 Lawrence A. Hyland (also of the Naval Research Laboratory), locates an aircraft for the first time.

1931 In Britain the first known proposal for a radar system came from William A. S. Butement and P. E. Pollard in January 1931. They equipped a ship with radar. As antennae were used parabolic dishes with horn radiator. Although their equipment produced short-range results the work was abandoned for lack of government support.

1933 On the basis of the in 1931 from himself invented sonar, Rudolph Kühnhold presented a so called “Funkmessgerät”. It worked on a wavelength of 48 cm and the transmitter had a power of about 40 Watts. From these tests, the Freya-radar was developed, which was produced in series beginning in 1938.

1935 Robert Watson-Watt (later: Sir Robert) suggested that radio waves might be used to detect aircraft at a distance and outlined a means of doing so. Intensive research began and by 1939 Britain possessed a defensive chain of highly secret Radio Direction Finding (RDF) stations.

1936 The development of the Klystron by the technicians George F. Metcalf and William C. Hahn, both General Electric. This will be an important component in radar units as an amplifier or an oscillator tube.

1939 Two engineers from the university in Birmingham, John Turton Randall und Henry Albert Howard Boot built a small but powerful radar using a Multicavity-Magnetron. The B–17 airplanes were fitted with this radar. Now they could find and thus combat the German submarines in the night and in fog.

1940 Different radar equipments are developed in the USA, Russia, Germany, France and Japan.

Driven by general war events and the development of the Air Force to major branch of service, the radar technology undergoes a strong development boost during the World War II, and radar sets were used during the “Cold War” in large numbers along the inner German border.

The Q-Code is a standardised collection of three-letter message encoding, also known as a Brevity Code, (Brevity Codes are used in amateur radio, maritime, aviation and military communications. The codes are designed to convey complex information with a few words or codes, all of which start with the letter “Q”), initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio. Although QCodes were created when radio used Morse Code exclusively, they continued to be employed after the introduction of voice transmissions. To avoid confusion, transmitter call signs are restricted; while an embedded three-letter Q sequence may occur (for instance when requested by an amateur radio station dedicated to low-power operation), no country is ever issued an ITU prefix starting with “Q”, (The International Telecommunication Union [ITU] allocates call sign prefixes for radio and television stations of all types). The codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services.

Early Developments

The original Q-Codes were created, about 1909, by the British government as a “list of abbreviations… prepared for the use of British ships and coast stations licensed by the Postmaster General. The Q-Codes facilitated communication between maritime radio operators speaking different languages, so they were soon adopted internationally. A total of forty-five Q-Codes appeared in the “List of Abbreviations to be used in Radio Communications”, which was included in the Service Regulations affixed to the Third International Radiotelegraph Convention in London (The Convention was signed on July 5, 1912, and became effective July 1, 1913.)

Later Usage

Over the years, modifications were made to the original Q-Codes to reflect changes in radio practice. Over a hundred Q-Codes were listed in the Post Office Handbook for Radio Operators in the 1970s and cover subjects such as meteorology, radio direction finding, radio procedures, search and rescue, and so on.

Some Q-Codes are also used in aviation and some in maritime. (A subset of Q-Codes is used by the Miami-Dade County, Florida local government for law enforcement and fire rescue communications, one of the few instances where Q-codes are used in ground voice communication.) Many military and other organizations that use Morse Code have adopted additional codes, including the Z-Code used by most European and NATO countries. Used in their formal “question/answer” sense, the meaning of a Q-code varies depending on whether or not the individual Q-code is sent as a question or an answer. For example, the message “QRP?” means “Shall I decrease transmitter power?”, and a reply of “QRP” means “Yes, decrease your transmitter power”. This structured use of Q-codes is fairly rare and now mainly limited to amateur radio and military Morse Code (CW) traffic networks.

Breakdown by Service •

QAA to QNZ – Assigned by the International Civil Aviation Organization (ICAO). •
QOA to QQZ – Reserved for the Maritime Services.
QRA to QUZ – Assigned by the International Telecommunications Union (ITU). •
QVA–QZZ – Are not allocated.

Amateur Radio

Selected Q-Codes were soon adopted by Amateur Radio Operators. In December, 1915, the American Radio Relay League (ARRL) began publication of a magazine titled “OST”, named after the Q-Code for “General call to all stations”. In Amateur Radio, the Q-Codes were originally used in Morse Code transmissions to shorten lengthy phrases and were followed by a Morse Code question mark (··–··) if the phrase was a question.

Q-Codes are commonly used in voice communications as shorthand nouns, verbs, and adjectives making up phrases. For example, an Amateur Radio Operator will complain about QRM (manmade interference), or tell another operator that there is “QSB on the signal”; “to QSY” is to change your operating frequency.

They can still be heard on HF communications but are not normally used on UHF and VHF communications. The reason is quite simple. Many radio amateurs have become certified purely to be volunteer communicators for their local emergency programs and consequently are not very familiar with the Q-Codes. Recently Q-Codes have again been used more for Morse Code communications than for voice communications.