Wavecom W61PC V7.5.0 - Manual (Page 194)

184  Transmission Modes WAVECOM Decoder W61PC/LAN Manual V7.5
NWR-SAME
NWR is the abbreviation for NOAA (National Oceanic and Atmospheric Administration [USA]) Weather Ra-
dio All Hazards, which is operated by the NWS (National Weather System). A similar system using the
same message format is operated as Weather radio Canada by the Meteorological Service of Canada.
Parameter Value
Frequency range VHF/UHF
Operation modes Broadcast
Modulation FM, SUB FSK
Center frequency 1822.9 Hz
Shift 800 Hz
Symbol rate 520.83 Bd
Receiver settings FM
Input format(s) AF, IF
SAME is the abbreviation for Specific Area Message Encoding.
This feature is incorporated in information regarding severe weather conditions, which is distributed by the
NWS. The area to which such a message applies is restricted by the area code, thus avoiding false alarm
in areas which are not affected by the weather condition which causes the alarm.
The coded message is transmitted, using Audio Frequency Shift Keying, on the audio channel of the NWR
transmitter system. Seven channels on 162.400, 162.425, 162.450, 162.475, 162.500, 161.525 and
162.550 MHz are assigned to this task.
The baud rate is 520.83 Bd the mark frequency is 2083.3 Hz and the space frequency 1562.5 Hz, all val-
ues fixed.
The user cannot change the audio frequency by tuning the receiver.
For this reason the center frequency is preset, as well as the baud rate.
The display shows the information of the messages split into its meaningful parts.
A message contains a preamble (sync word), a data header part, an alert tone signal (if applicable), a
voice message part and an end-of-message part. The data part format is as follows:
ZCZC-ORG-EEE-PSSCCC-PSSCCC+TTTT-JJJHHMM-LLLLLLLL
ZCZC Start-of-message header block code
ORG Originator header block code
EEE Event header block code
PSSCCC Geographical area header block code
TTTT Purge time header code block
JJJHHMM Original dissemination time header block (Julian date, UTC)
LLLLLLLL Message originator header block
The area-code (PSSCCC) is divided into state, county and subpart-code, the dissemination date is divided
into day, hour and minute.
If the message originator (LLLLLLLL) is a NWS office, the ICAO location identifiers are used, e.g.
KDTX/NWS. If the message is a re-broadcast, the call sign of the broadcast station is used, e.g. KFAB/AM
or WDAF/FM.