SPREAD

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SPREAD
SPREAD.jpg
Frequencies 3 MHz,30 MHz
Frequency Range 3 MHz - 30 MHz
Mode USB
Modulation FSK
ACF
Bandwidth 600 Hz
Location Worldwide
Short Description SPREAD, also known as AUTOSPEC Mk2, SPREAD-11, SPREAD-21, and SPREAD-51, was a FEC system used by Romanian diplomatic stations and the Brazilian Navy and shore stations. SPREAD is considered the successor to AUTOSPEC.
I/Q Raw Recording
Audio Sample

SPREAD, also known as AUTOSPEC Mk2, SPREAD-11, SPREAD-21, and SPREAD-51, was a FECForward Error Correction system used by Romanian diplomatic stations and the Brazilian Navy and shore stations. SPREAD is considered the successor to AUTOSPEC, and like AUTOSPEC, used the 10-bit Bauer code. SPREAD is named so because it spreads bits after the 10-bit bauer code.

Three variants of SPREAD exist, SPREAD-11, SPREAD-21, and SPREAD-51.

  • For SPREAD-11, after each bit of the 10-bit Bauer code, 10 data bits from other characters are sent.
  • For SPREAD-21, after each bit of the 10-bit Bauer code, 20 data bits from other characters are sent.
  • For SPREAD-51, after each bit of the 10-bit Bauer code, 50 data bits from other characters are sent.

The spreading of bits helps to improve the data transfer reliability.

SPREAD uses a 410 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). FSKFrequency-Shift Keying shift, and had been mostly seen at 68.5 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second., 102.7 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. and 137 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. with 218 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. seen seldomly.

Samples[edit]

SPREAD-51:

Decoding Software[edit]

Professional Equipment/Software
  • Hoka Code 300-32
  • Shoc go2decode
  • Shoc go2monitor
  • Wavecom W-Code
  • Wavecom W-Spectra

Additional Links[edit]

Additional Images[edit]