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Transmission Modes
WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0
DNCS IWM: Interrogation with Message
PRM: Picket Reply Message
SB: Short Broadcast
Net Test
The data in the frames is coded with Hamming method.
To decode the mode, choose the correct Polarity, put the Doppler Tone cursor in the FFT tuning window to
the Doppler tone. Small frequency error (+/- 30 Hz) and Doppler shift will be corrected automatically and
displayed in the Freq Err/Doppler Shift field. The data will be displayed in the main text window. Because
the mode transmits link information, the data is displayed in a 30-bit group hex.
The frame format is displayed together with the baudrate in the Format field. Confidence shows the de-
coding quality: a value over 95 means the FEC has probably corrected all bit errors, the data decoded is
mostly reliable.
MD-674 ASYNC
MD-674 is an asynchronous FSK system and is based on ASCII. No error detection or error correction is
implemented.
Parameter
Value
Frequency range
HF
Operation modes
Broadcast
Modulation
FSK
Center frequency
1275 Hz
Shift
85 Hz
Symbol rate
50, 75, 100 and 150 Bd
Modulation
FSK
Receiver settings
DATA, CW, LSB or USB
Input format(s)
AF, IF
Additional Info
Async FSK only
For MD-674 mode standard baud rates from 50 to 150 Bd are available. Non-standard baud rates may be
selected using the
Baudrate
menu item.
From “
Options | Alphabet...”
ITA5 and ITA2 are available as output formats.
MD-674 is also known as Wireline FSK.
METEOSAT
The METEOSAT software has been specifically tailored to the transmissions of meteorological satellites
parked in geo-stationary orbit at 0.2 degrees East and transmitting on 1691.0 MHz. Transmissions are al-
ways at 240 rpm using an IOC of 288. In contrast to short-wave stations which use frequency modulation,
satellite weather images are transmitted using amplitude modulation. For this purpose the decoder is fit-
ted with a DSP AM demodulator with an integrated software FIR low-pass filter.
Parameter
Value
Frequency range
VHF/UHF
Operation modes
Broadcast
Modulation
FM, SUB AM
Speed
240 RPM