A radiogram is a formal written message transmitted by radio. Also known as a radio telegram or radio telegraphic message, radiograms use a standardized message format, form and radiotelephone and/or radiotelegraph transmission procedures. These procedures typically provide a means of transmitting the content of the messages without including the names of the various headers and message sections, so as to minimize the time needed to transmit messages over limited and/or congested radio channels. Various formats have been used historically by maritime radio services, military organizations, and Amateur Radio organizations.
Radiograms are typically employed for conducting Record communications, which provides a message transmission and delivery audit trail. Sometimes these records are kept for proprietary purposes internal to the organization sending them, but are also sometimes legally defined as public records. For example, maritime Mayday/SOS messages transmitted by radio are defined by international agreements as public records.
Historical development
From 1850 to the mid 20th century industrial countries used the electric telegraph as a long distance person-to-person text message service. A telegraph system consisted of two or more geographically separated stations linked by wire supported on telegraph poles. A message was sent by an operator in one station tapping on a telegraph key, which sent pulses of current from a battery or generator down the wire to the receiving station, spelling out the text message in Morse code. At the receiving station the current would activate a telegraph sounder which would produce a series of audible clicks, and a receiving operator who knew Morse code would translate the clicks to text and write down the message. By the 1870s, most industrial nations had nationwide telegraph networks with telegraph offices in most towns, allowing citizens to send a message called a telegram for a fee to any person in the country. Submarine telegraph cables allowed intercontinental messages called cablegrams.
The invention of radiotelegraphy (wireless telegraphy) communication around 1900 allowed telegraph signals to be sent by radio. An operator at a radio transmitter would tap on a telegraph key, turning the transmitter on and off, sending pulses of radio waves through the air, and at the receiving station a radio receiver would receive the pulses and make them audible as a sequence of beeps in the earphone, and the receiving operator would translate the Morse code to text and write it down. High speed systems used paper tape to send and record the message. Guglielmo Marconi's demonstration of transatlantic radiotelegraphy transmission in 1901 showed that the wireless telegraph could be a useful long-distance communication technology which didn't require the costly installation of a telegraph wire. Around 1906 industrial nations began building powerful transoceanic radiotelegraphy stations to communicate with other countries and their overseas colonies. By World War I these were integrated with landline telegraph networks, so citizens could go to a telegraph office and send a person-to-person telegraph message by radio to another country. This was written down on a standardized form called a radiogram. International radiotelegraphy was expensive so radiograms were mostly used for business and commercial communication.
The concept of the standard message format originated in the wired telegraph services. Each telegraph company likely had its own format, but soon after radio telegraph services began, some elements of the message exchange format were codified in international conventions (such as the International Radiotelegraph Convention, Washington, 1927), and these were then often duplicated in domestic radio communications regulations (such as the FCC in the U.S.) and in military procedure documentation.
Military organizations independently developed their own procedures, and in addition to differing from the international procedures, they sometimes differed between different branches of the military within the same country.
For example, the publication "Communication Instructions, 1929", from the U.S. Navy Department, includes:
One procedure for messages transmitted "in naval form over nonnaval systems" (Part II: Radio, Chapter 15)
One procedure for exchanging messages with commercial radio stations (Part II: Radio, Chapter 16, pages 36–37 for examples; see also Part I: Chapter 7)
One procedure for messages transmitted within the Navy (Part IV: Procedure and Examples, Chapter 32, especially pages 21 & 22 for the format)
One format for exchanging messages between the Army and Navy (Part IV: Appendix A), called the "Joint Army and Navy Radiotelegraph Procedure", with the format shown on page 70.
Notable characteristics of radiograms include headers that include information such as the from and to addresses, date and time filed, and precedence (e.g. emergency, priority, or routine), so that the radio operators can determine which messages need to be delivered first during times of congestion.
Chronology of the commercial radiogram format
International Telegraph Conference (London, 1903; including Order of transmission beginning on page 40)[1]
International Telegraph Conference (Paris, 1925)[2]
International Radiotelegraph Convention (Washington, 1927)
International Radiotelegraph Conference (Madrid, 1932) was redrafted to include general principles common to telegraph, telephone and radio services.
Maritime radio service radiotelegrams
The message format for communications transmitted to sea-going vessels is defined in Rec. ITU-R M.1171, § 28:[3]
radiotelegram begins: from . . . (name of ship or aircraft);
number . . . (serial number of radiotelegram);
number of words . . .;
date . . .;
time . . . (time radiotelegram was handed in aboard ship or aircraft);
service indicators (if any);
address . . .;
text . . .;
signature . . . (if any);
radiotelegram ends, over
Airline Teletype Message
The international airline industry continues to use a radioteletype message format originally designed for transmission to Teleprinters, Airline Teletype System, which is now disseminated via e-mail and other modern electronic formats. However, the relationship of the IATA Type B message to other radio telegram message formats is clearly visible in a typical message:
QD AAABBCC .XXXYYZZ 111301 ASM UTC 27SEP03899E001/TSTF DL Y NEW BA667/13APR J 319 C1M25VVA4C26 LHR1340 BCN1610 LHRQQQ 99/1 QQQBCN 98/A QQQQQQ 906/PAYDIV B LHRQQQ 999/1 QQQBCN 998/A SI
Military radiograms
Military organizations have historically used radiograms for transmitting messages. One notable example is the notification of the air raid on Pearl Harbor[4] that brought the United States into World War II.
The standard military radiogram format (in NATO allied nations) is known as the 16-line message format, for the manner in which a paper message form is transcribed through voice, Morse code, or TTY transmission formats. Each format line contains pre-defined content.
When sent as an ACP-126 message over teletype, a 16-line format radiogram would appear similar to this:
RFHT DE RFG NR 114 R 151412Z MAR FM CG FIFTH CORPS TO CG THIRD INFDIV WD GRNC BT UNCLAS PLAINDRESS SINGLE ADDRESS MESSAGES WILL BE TRANSMITTED OVER TELETIPWRITER <!-- sic --> CIRCUITS AS INDICATED IN THIS EXAMPLE BT C WA OVER TELETYPEWRITER NNNN
Some of the format lines in the above example have been omitted for efficiency. The translation of this abbreviate format follows:
Format Line
Message Text
Explanation
Line 2
RFHT
Station being called, which will receive the message
Line 3
DE RFG NR 114
Sent by radio station having the callsign RFG, station serial number 114
Line 5
R 151412Z MAR
Routine precedence, March 15, 2:12pm UTC in Date-time group format
Line 6
FM CG FIFTH CORPS
The message is from CG FIFTH CORPS
Line 7
TO CG THIRD INFDIV
The message is to CG THIRD INFDIV
Line 10
WD GRNC
Accounting symbol (WD); word groups have not been counted (GRNC)
Line 11
BT
Section separator between heading and text
Line 12
UNCLAS
PLAINDRESS SINGLE ADDRESS
MESSAGES WILL BE TRANSMITTED
OVER TELETIPWRITER CIRCUITS
AS INDICATED IN THIS EXAMPLE
Message content is unclassified, and the message is...
Line 13
BT
Section separator between text and the ending
Line 15
C WA OVER TELETYPEWRITER
corrects (C) word after (WA) "OVER" to "TELETYPEWRITER"
Line 16
NNNN
end-of-message indicator
This radiotelegraph message format (also "radio teletype message format", "teletypewriter message format", and "radiotelephone message format") and transmission procedures have been documented in numerous military standards, including the World War II-era U.S. Army Manuals TM 11-454 (The Radio Operator), FM 24-5 (Basic Field Manual, Signal Communication),[5] FM 24-6 (Radio Operator's Manual),[6] TM 1-460 (Radiotelephone Procedure), FM 24-18 (Radio Communication), FM-24-19 (Radio Operator's Handbook), FM 101-5-2 (U.S. Army Report and Message Formats), TM 11-380, FM 11-490-7 (Military Affiliate Radio System), AR 105–75, Navy Department Communication Instructions 1929,[7] and their modern decedents in the Allied Communications Procedures, including ACP 124 (messages relayed by telegraphy), ACP 125 (messages relayed by voice), ACP 126 (messages relayed by radio teletype), ACP 127 (messages relayed by automated tape), AR 25–6, U.S. Navy Signalman training courses[8][9] and others.
At one point before World War II, the U.S. FCC defined (at least for domestic police radio traffic) a station serial number as a sequential message number that was reset at the beginning of each calendar month.[10]
The Communications Standard Dictionary defines radiotelegraph message format as "The prescribed arrangement of the parts of a message that has been prepared for radiotelegraph transmission."[11]
MARS radiograms
The Military Affiliate Radio System uses radiograms, or MARSgrams,[12] to transmit health & welfare message between military members and their families, and also for emergency communications. Some MARS radio procedure documents include instructions on how to exchange ARRL NTS Radiograms over a MARS radio net. Both formats include a procedure for counting the number of word groups (words in NTS, groups in the ACP/MARS format), but differ in how word groups are counted, for instance, so the counting method must be resolved when converting messages between formats.
U.S. Department of State ACP-127 radiograms
The U.S. Department of State uses the military's automated message delivery version of the 16-line format, known as ACP-127, with its own structured definitions of the format lines.[13]
Police Radiogram
Police radiograms had their own format, likely derived from the commercial radiogram format.
Example radiogram from A National Training Manual and Procedural Guide for Police and Public Safety Radio Communications Personnel, 1968.[14]
15 SHRF LEE COUNTY ILL 12-20-66 (A. Preamble) PD CARBONDALE ILL (B. Address) DATA AND DISPOSITION RED 62 CHEVROLET (C. Text) 4 DOOR ILL LL1948 VIN 21723T58723 ABANDONED DIXON ILLINOIS THREE DAYS HELD ANDREWS GARAGE FRONT END DAMAGED NOT DRIVEABLE NO APPREHENSIONS WILL BE RELEASED TO OWNER ON PROOF OF OWNERSHIP SHERIFF LEE COUNTY ILLINOIS JRM 1530 CST (D. Signature)
Section A6.6 Message Form
From the above training manual:
A formal message is one constructed, transmitted and recorded according to a standard prescribed form (see Sec. 4). A formal message should contain the following essential P A R T S:
Preamble - message number, point of origin or agency identifier, date.
Address - to whom the message is directed.
Reference - to previous message, if any.
Text - the message.
Signature or Authority - department requesting the message.
An ARRL radiogram is an instance of formal written message traffic routed by a network of amateur radio operators through traffic nets, called the National Traffic System (NTS).
It is a plaintext message, along with relevant metadata (headers), that is placed into a traffic net by an amateur radio operator. Each radiogram is relayed, possibly through one or more other amateur radio operators, to a radio operator who volunteers to deliver the radiogram content to its destination.
VOA Radiogram
VOA Radiogram was an experimental Voice of America program, aired from 2012 to 2017, which broadcasts digital text and images via shortwave radiograms [15] This digital stream can be decoded using a basic AMshortwave receiver and freely downloadable software of the Fldigi family. This software is available for Windows, Apple (macOS), Linux, and FreeBSD systems.
The mode used most often on VOA Radiogram, for both text and images, is MFSK32, but other modes are occasionally transmitted.
Broadcasts were made via the Edward R. Murrow transmitting station in North Carolina on the following schedule:[15]
Due to the retirement of Dr. Kim Andrew Elliott from VOA and the decision of VOA to not replace his role with the program,[16] VOA Radiogram program's final airing was on June 17–18, 2017,[17] however Elliott will be continuing to air Radiograms via commercial shortwave stations under the name of "Shortwave Radiogram."[18][19]
Related Research Articles
Morse code is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs. Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy.
Wireless telegraphy or radiotelegraphy is the transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term wireless telegraphy was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in Morse code. In a manual system, the sending operator taps on a switch called a telegraph key which turns the transmitter on and off, producing the pulses of radio waves. At the receiver the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code.
A radio net is three or more radio stations communicating with each other on a common channel or frequency. A net is essentially a moderated conference call conducted over two-way radio, typically in half-duplex operating conditions. The use of half-duplex operation requires a very particular set of operating procedures to be followed in order to avoid inefficiencies and chaos.
The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially amateur radio. To distinguish the use of a Q-code transmitted as a question from the same Q-code transmitted as a statement, operators either prefixed it with the military network question marker "INT" or suffixed it with the standard Morse question mark UD.
SOS is a Morse code distress signal, used internationally, originally established for maritime use. In formal notation SOS is written with an overscore line, to indicate that the Morse code equivalents for the individual letters of "SOS" are transmitted as an unbroken sequence of three dots / three dashes / three dots, with no spaces between the letters. In International Morse Code three dots form the letter "S" and three dashes make the letter "O", so "S O S" became a common way to remember the order of the dots and dashes. IWB, VZE, 3B, and V7 form equivalent sequences, but traditionally SOS is the easiest to remember.
Ten-codes, officially known as ten signals, are brevity codes used to represent common phrases in voice communication, particularly by US public safety officials and in citizens band (CB) radio transmissions. The police version of ten-codes is officially known as the APCO Project 14 Aural Brevity Code.
A radiotelephone, abbreviated RT, is a radio communication system for conducting a conversation; radiotelephony means telephony by radio. It is in contrast to radiotelegraphy, which is radio transmission of telegrams (messages), or television, transmission of moving pictures and sound. The term is related to radio broadcasting, which transmit audio one way to listeners. Radiotelephony refers specifically to two-way radio systems for bidirectional person-to-person voice communication between separated users, such as CB radio or marine radio. In spite of the name, radiotelephony systems are not necessarily connected to or have anything to do with the telephone network, and in some radio services, including GMRS, interconnection is prohibited.
A signal strength and readability report is a standardized format for reporting the strength of the radio signal and the readability (quality) of the radiotelephone (voice) or radiotelegraph signal transmitted by another station as received at the reporting station's location and by their radio station equipment. These report formats are usually designed for only one communications mode or the other, although a few are used for both telegraph and voice communications. All but one of these signal report formats involve the transmission of numbers.
Radiotelephony procedure includes various techniques used to clarify, simplify and standardize spoken communications over two-way radios, in use by the armed forces, in civil aviation, police and fire dispatching systems, citizens' band radio (CB), and amateur radio.
Message precedence is an indicator attached to a message indicating its level of urgency, and used in the exchange of radiograms in radiotelegraph and radiotelephony procedures. Email header fields can also provide a precedence flag.
CQ is a station code used by wireless operators derived from long established telegraphic practice on undersea cables and landlines, particularly used by those communicating in Morse code,, but also by voice operators, to make a general call. Transmitting the letters CQ on a particular radio frequency means that the transmission is a broadcast or "General Call" to anyone listening, and when the operator sends "K" or says "Go Ahead" it is an invitation for any licensed radio station listening on that frequency to respond. Its use on radio matched the existing use on Morse landline telegraphy and dates from the earliest wireless stations. It was widely used in point-to-point diplomatic and press services, maritime, aviation, and police services until those services eliminated Morse radiotelegraphy. It is still widely used in amateur radio which still has active use of Morse radiotelegraphy.
A Radio code is any code that is commonly used over a telecommunication system such as Morse code, brevity codes and procedure words.
Procedural signs or prosigns are shorthand signals used in Morse code telegraphy, for the purpose of simplifying and standardizing procedural protocols for landline and radio communication. The procedural signs are distinct from conventional Morse code abbreviations, which consist mainly of brevity codes that convey messages to other parties with greater speed and accuracy. However, some codes are used both as prosigns and as single letters or punctuation marks, and for those, the distinction between a prosign and abbreviation is ambiguous, even in context.
Procedure words are words or phrases limited to radiotelephony procedure used to facilitate communication by conveying information in a condensed standard verbal format. Prowords are voice versions of the much older procedural signs for Morse code which were first developed in the 1860s for Morse telegraphy, and their meaning is identical.
A plain-language radio check is the means of requesting and giving a signal strength and readability report for radiotelephony (voice) communications, and is the direct equivalent to the QSA and QRK code used to give the same report in radiotelegraph communications. SINPEMFO code is the voice signal reporting format developed by the ITU in 1959, but sees little use outside of shortwave listeners.
16-line message format, or Basic Message Format, is the standard military radiogram format for the manner in which a paper message form is transcribed through voice, Morse code, or TTY transmission formats. The overall structure of the message has three parts: HEADING, TEXT, and ENDING. This heading is further divided into procedure, preamble, address, and prefix. Each format line contains pre-defined content. An actual message may have fewer than 16 actual lines, or far more than 16, because some lines are skipped in some delivery methods, and a long message may have a TEXT portion that is longer than 16 lines by itself.
Fldigi is a free and open-source program which allows an ordinary computer's sound card to be used as a simple two-way data modem. The software is mostly used by amateur radio operators who connect the microphone and headphone connections of an amateur radio SSB or FM transceiver to the computer's headphone and microphone connections, respectively.
The QSA code and QRK code are interrelated and complementary signal reporting codes for use in wireless telegraphy. An enhanced format, SINPO code, was published in the ITU Radio Regulations, Geneva, 1959, but is longer and unwieldy for use in the fast pace of Morse code communications.
Allied Communication Procedures is the set of manuals and supplements published by the Combined Communications Electronics Board that prescribe the methods and standards to be used while conducting visual, audible, radiotelegraph, and radiotelephone communications within NATO member nations. These procedures relate to procedure words, radiotelephony procedure, Allied Military phonetic spelling alphabets, plain language radio checks, the 16-line message format (radiogram), and others.
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