Saab Grintek MHF-50 MFSK Modem
The MHF-50 MFSKMultiple Frequency Shift-Keying Modem by Saab Grintek Technologies in South Africa is a data modem that utilizes RTTYRadio TeleTYpe, 2-FSKFrequency-Shift Keying, and 33-MFSKMultiple Frequency Shift-Keying to transmit data. The unique format of the signal makes it easy to identify. The preamble consists of an RTTYRadio TeleTYpe 50Bd with 170 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). shift followed by a long tone, then a 2-FSKFrequency-Shift Keying starter with 390 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). shift and 54.4 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. Then, the main data portion of the signal is a 2200 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). wide 33-MFSKMultiple Frequency Shift-Keying signal, with a 3-tone sequence to mark the end of the transmission.
The primary user of this modem is the South African Navy.
|RTTYRadio TeleTYpe Preamble||2-FSKFrequency-Shift Keying Preamble||MFSKMultiple Frequency Shift-Keying-33 Data||MFSKMultiple Frequency Shift-Keying-33 EOTEnd of Transmission|
8580 kHzKiloHertz (kHz) 10^3 Hz is a common frequency for this signal, and is often paired with 4346, 6504 and 12982 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables). They all carry the same message(s) over and over so they are believed to be either channel markers, propagation markers and/or information about status of other South African Navy working channels on the bands. 4245, 6407, 6493 and 8603 kHzKiloHertz (kHz) 10^3 Hz are believed to be the above mentioned working channels and carry the actual messages because the length of transmissions may vary.
- South African Naval MFSK-8580 kHz
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- Saab Grintek (South African Navy) - MFSK 54 bauds - 6504 kHz
- RadioScanner.RU South African Navy
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