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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.
Contents
- Historical development
- Chronology of the commercial radiogram format
- Maritime radio service radiotelegrams
- Airline Teletype Message
- Military radiograms
- MARS radiograms
- US Department of State ACP 127 radiograms
- Police Radiogram
- Section A66 Message Form
- ARRL radiogram
- VOA Radiogram
- References
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
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:
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
Maritime radio service radiotelegrams
The message format for communications transmitted to sea-going vessels is defined in Rec. ITU-R M.1171, § 28:
- 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 111301ASMUTC27SEP03899E001/TSTF DL YNEWBA667/13APRJ 319 C1M25VVA4C26LHR1340 BCN1610LHRQQQ 99/1QQQBCN 98/AQQQQQQ 906/PAYDIV BLHRQQQ 999/1QQQBCN 998/ASIMilitary radiograms
Military organizations have historically used radiograms for transmitting messages. One notable example is the notification of the air raid on Pearl Harbor 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:
RFHTDE RFG NR 114R 151412Z MARFM CG FIFTH CORPSTO CG THIRD INFDIVWD GRNCBTUNCLASPLAINDRESS SINGLE ADDRESSMESSAGES WILL BE TRANSMITTEDOVER TELETIPEWRITER CIRCUITSAS INDICATED IN THIS EXAMPLEBTC WA OVER TELETYPEWRITERNNNNSome of the format lines in the above example have been omitted for efficiency. The translation of this abbreviate format follows:
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), FM 24-6 (Radio Operator's Manual), 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, 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 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.
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."
This example of an USMTF message contains a good summary of the message creation and handling rules.
MARS radiograms
The Military Affiliate Radio System uses radiograms, or MARSgrams, 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.
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.
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 21723T58723ABANDONED DIXON ILLINOIS THREE DAYSHELD ANDREWS GARAGE FRONT END DAMAGEDNOT DRIVEABLE NO APPREHENSIONS WILLBE RELEASED TO OWNER ON PROOF OFOWNERSHIPSHERIFF LEE COUNTYILLINOIS 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.
ARRL radiogram
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 is an experimental Voice of America program, started in 2012, which broadcasts digital text and images via shortwave radiograms This digital stream can be decoded using a basic AM shortwave receiver and freely downloadable software of the Fldigi family. This software is available for Windows, Apple (OSX), 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.