Anyone who has listened to broadcast radio knows at least a little about station identification requirements; I certainly remember listening to the Indy 500 coverage back in my youth (I grew up in Indianapolis, so we were blacked out for TV coverage and could only listen to the race on the radio) and remember well the periodic interruption of the coverage with "We now pause 15 seconds for station identification" followed by WIBC's identification as the network flagship station. The general rule is that radio stations must, from time to time, transmit identification so that listeners will know who is transmitting. The main regulatory reason for this is so that a station that is suffering harmful interference from another station can, merely by listening long enough, identify who that station is and seek relief appropriately, or determine that they are not entitled to relief. Amateur radio stations are no exception to this general rule, although the specific requirements are different than for the broadcast services.
The general rule for identification in the amateur radio service in the United States (§97.119) is that station identification is required at the end
of a transmission or series of transmissions, and at least once every ten minutes during a transmission or series of transmissions which lasts longer than ten minutes. Note that there is no requirement to identify at the start of a series of transmissions, and identification at the start of a series of transmissions is insufficient to meet the requirements of the rule. In general, the best way to remain in compliance with the rules is to ensure that you always end out your transmission with your identification.
In general, transmissions which do not include identification (known as "unidentified communications or signals") are prohibited, with two very specific exceptions. First, stations operating more than 50 kilometers above the earth's surface ("space stations") are not required to identify under any circumstance. Second, stations being used solely to control a model craft (via telecommand) are not required to identify provided that the transmitter being used has a label affixed to it identifying the licensee's call sign, name, and address, and that the transmitter's power does not exceed one watt. Note that while telecommand signals sent to a space station are permitted to be encrypted
, such transmissions are not exempt from identification. The only type of transmission which is both exempt from identification and permitted to be encrypted is telecommand of a model craft under §97.218.
The identification itself must be a call sign. In general, it'll be the call sign of the operator, but there are several situations in which it can be a different call sign. In general, when operating someone else's station you are supposed to use their call sign, not your own call sign. When operating a station owned by, or being operated on behalf of, a club, the operator should identify using the club's call sign. Also, a station which is operating within the scope of a "special event" may identify using the temporarily assigned special event call sign in lieu of his or her own call sign. In all of these cases, the operator must have the permission of the station owner, the club's trustee or the special event coordinator (respectively) in order to use the call sign. Furthermore, when using a temporarily-issued special event call sign the operator must identify with his or her own call sign at least once in every hour; however, this is not required when using someone else's permanently-issued station or club call sign.
The rules stipulate that station identifications must be transmitted in one of four formats: Morse code, phone (in English), RTTY, or a video format as specified in §73.682(a) (which is part of the FCC's standards for broadcast video); the latter two options apply only if the transmission being identified was in a digital mode or video mode, respectively. In practice, very few stations transmitting digital modes other than RTTY identify in RTTY, identifying instead in the same mode as the transmission, and the FCC has yet to take action against any station for failing to identify, but that's what the rules require. (The regulations relating to digital modes are rather out of date in places, and actual practice is often rather at odds with the regulations, but nobody seems to care a whole lot.)
There's a lot of common myths in the amateur community relating to identification. A common one that is seen with older VHF ragchewers is the practice of identifying in a roundtable with "K9XYZ and the group, this is W9ZXY", and some hams seem to think that this practice is mandatory. The regulations never mandate transmitting the call sign of any station other than that the station transmitting. It is not necessary (in regulation, at least) to identify the intended recipient of the transmission. This particular practice seems to have arisen from an overly zealous interpretation of the regulations relating to broadcasting; someone decided that all communications had to involve exactly two stations, and that identifying in this manner would somehow satisfy this regulation. The only requirements for two (or more) stations who are communicating with one another is that each station must end its final transmission in the exchange with its own call sign, and each station must identify with its own call sign at least once every ten minutes during the sequence of communications.
There's a few situations in which one is required to add indicators either before or after one's call sign, when identifying. If you're operating someone else's station and you are exceeding the privileges alloted to the licensee of that station, you are required to identify by using the station owner's call sign followed by your own call sign, to explain why that station is entitled to operate in those frequencies or modes. There's also three special suffix indicators (/KT, /AG, and /AE) used to indicate that the station operator has recently upgraded and is using the privileges gained thereby pending the processing of the upgrade by the FCC. These are pretty rare now, though, given the speed with which the FCC processes upgrades
these days. Also, when operating in the United States pursuant to a reciprocity grant, the alien operator is required to prefix his or her own (non-US) call sign with a call sign prefix identifying the location of the station. Perversely, for Canadians this goes after, not before, the call sign. (The same rule applies for a US licensee operating in another country, except, of course, in reverse.) Licensees may add additional voluntary designations either before or after their call sign if they so choose, as long as such designations do not conflict with any of the official ones. It's quite common to see "/R" added to repeater station identifications, for example, even though this is (no longer) required by the rules, and many older hams will reflexively add "mobile" to their identification when operating mobile because that used to be required
. The requirement of not conflicting with official designations effectively eliminates most voluntary prefix options because nearly every possible code is a valid national prefix
and would therefore be in conflict. (Out of 1296 possible two-character codes, 1034 are currently assigned.) However, voluntary suffix options are pretty much wide open.
Speaking of myths regarding identification, the NCVEC perpetuates the myth that the "KT", "AG", and "AE" suffixes are initialisms in question T2B11, which tests whether you know that "AG" supposedly means "Authorized General". The regulations do not specify the use of "Authorized General" when identifying in English when operating pursuant to a CSCE granting General privileges; they specify the specific use of the suffix "AG", which in phone would be "Alpha Golf". The reason "KT" is used for Technicians instead of "AT" (which would make more sense) is because "AT" is not a call sign prefix available to the FCC (it's allocated to India) and the FCC, when it selected those suffixes, wished to avoid conflict with other possible uses. "Authorized General" is essentially a backronym from the fundamentally meaningless code. (T2B11 is another example of a bad question; fortunately, this one, like the other bad question I wrote about a while ago
, appears to have been dropped from the 2010 version of the pool.)This post has been brought to you by pool questions T2A05, T2B01, T2B02, T2B03, T2B04, T2B05, T2B06, T2B07, T2B08, T2B09, T2B10, and T2B11. Section references above are to Title 47 of the Code of Federal Regulations, browsable via the GPO Access eCFR service.