SITOR

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SITOR (simplex teletype over radio) is a transmission mode used to transmit textual messages akin to regular radioteletype (RTTY), but implements simple error correction.

Comparisons of MT63, RTTY and HF Packet bandwidth usage

Two modes of SITOR are used:

SITOR-A which implements automatic repeat request (ARQ) -- sometimes called AMTOR
SITOR-B which implements forward error correction (FEC)

SITOR is used commonly on shortwave bands, where it is used to transmit maritime-related information such as weather forecasts and storm warnings. In the United States, it is regularly used by the United States Coast Guard.

SITOR has an aurally easy to identify idling pattern. Synchronization bursts are transmitted every second or so and last for slightly more than one second. Every few sync bursts, a Morse identifier of three letters is transmitted (for example NMO in Honolulu).

SITOR idling pattern (file info) — play in browser (beta)
- Listen to a sample of a SITOR idler pattern, from the U.S. Coast Guard station NMC (Point Reyes). The letterns "NMC" are also transmitted in Morse.
- Problems listening to the file? See media help.