Codes and Alphabets

Related wiki pages: Calculators

CW Abbreviations
These abbreviations are commonly used in CW transmissions to shorten transmission times. Not all CW operators use all of them - most will use very few. As a general rule most operators do not abbreviate unnecessarily, especially when communication with an operator that they do not know or whose experience is unknown. In contest conditions, abbreviations are common as operators try to gain as many contacts as possible over the competition period.

In 1859, Western Union standardized on the "92 code", a series of telegraphic abbreviations in which numbers (originally 1 to 92) were assigned meanings. These were later included as part of the "Philips Code", a series of abbreviations first published in 1879 by Walter Phillips of the Associated Press for use in the telegraphic transmission of press dispatches.

While most of the codes have fallen into disuse, the form 19 and 31 train orders remained in railroad use long beyond the end of landline telegraphy, the use of '30' at the end of a news wire story was continued through the teletypewriter era and the '73' and '88' greetings remain in use in amateur radiotelegraphy.

Two non-standard codes, rarely-used, were coined within the amateur radiotelegraph service. The Young Ladies Radio League (YLRL) organized in 1939 and quickly coined '33' as "Love sealed with mutual respect and friendship between one YL and another YL". More recently, '72' has been used in QRP operation to signify a '73' sent with reduced transmitter power.

Morse Code
International Morse code is composed of five elements:


 * 1) short mark, dot or 'dit' (·) — one unit long
 * 2) longer mark, dash or 'dah' (–) — three units long
 * 3) intra-character gap (between the dots and dashes within a character) — one unit long
 * 4) short gap (between letters) — three units long
 * 5) medium gap (between words) — seven units long

Radio traffic uses International Morse only; while the original railroad landline telegraph system used American Morse code, this code is now obsolete.

External link : Morse Code

Phonetic Alphabet - Nato
A number of phonetic alphabets exist. The NATO version is most common and can be considered to be the "international" phonetic alphabet.

Q-Code
These codes were originally developed to shorten transmission times when using CW, but are frequently used in voice transmissions. (eg. I am going to go QRT, thanks for the QSO.)

The QRA...QUZ code range includes phrases applicable to all services and is allocated to the International Telecommunications Union. NATO's ACP 131(E), COMMUNICATIONS INSTRUCTIONS - OPERATING SIGNALS, March 1997, chapter 2 contains a full list of 'Q' codes. Other 'Q' code ranges are allocated specifically to aviation or maritime services; many of those codes have fallen into disuse as voice displaces CW in commercial operation.

The Q-code was originally instituted at the Radiotelegraph Convention held in London, 1912 and was intended for marine radiotelegraph use. The codes were based on an earlier list published by the British postmaster general's office in 1908. More information about the history and usage of Q-codes can be found here.

RSQ code
Often used to describe reception and quality of digital modes such as PSK31

RST code
The RST code, in its original form, is intended for CW operation. On SSB, the final digit (tone) is normally omitted.

In CW operation, individual digits may be abbreviated by substituting as follows: 1 = A,  2 = U,   3 = V,   4 = 4,   5 = E,   6 = 6,   7 = B,   8 = D,   9 = N,   0 = T (for instance, RST 599 could be sent as 5NN - a shorter message in CW). These are referred to as "cut numbers" and are obtained by replacing all of the dashes in a CW digit with a single dash. Cut numbers are not suitable for transmitting data which already contains mixed alphanumerics, such as callsigns.

RSV code for SSTV transmissions
In fast-scan amateur television (ATV), signal-to-noise ratio is reported as one of:
 * P0 - all image detail lost
 * P1 - 3-8dB, barely legible
 * P2 - 8-20dB, definitely noisy
 * P3 - 20-35dB, somewhat noisy
 * P4 - 35-45dB, slightly noisy
 * P5 - 45dB+, no discernible noise