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649
NOXX20 KWBC 291923
ADMEMW
NATIONAL ADMINISTRATIVE MESSAGE FOR EMWIN
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
300 PM EDT FRI JUN 29 2001
TO: EMERGENCY MANAGERS WEATHER INFORMATION NETWORK /EMWIN/
USERS
FROM: WILLIAM BROCKMAN
CHIEF...TELECOMMUNICATION OPERATIONS CENTER
NATIONAL WEATHER SERVICE /NWS/
AND
GERALD DITTBERNER
CHIEF...ADVANCED SYSTEMS PLANNING DIVISION
NATIONAL ENVIRONMENTAL SATELLITE...DATA...AND
INFORMATION SERVICE /NESDIS/
SUBJECT: EMWIN TRANSITION UPDATE 6/29/01
THIS MESSAGE IS THE SECOND IN A SERIES OF TRANSITION UPDATE
MESSAGES TO INFORM EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
/EMWIN/ USERS OF NEW INFORMATION REGARDING THE TRANSITION OF THE
EMWIN DATASTREAM. THE FIRST EMWIN TRANSITION UPDATE...DATED
APRIL 27...AND FUTURE EMWIN TRANSITION UPDATES WILL BE
DISTRIBUTED THROUGH EMWIN AND POSTED ON THE EMWIN HOME PAGE AT
/USE LOWER CASE/:
HTTP://IWIN.NWS.NOAA.GOV/EMWIN/INDEX.HTM
THE EMWIN HOME PAGE HAS BEEN REVISED AND UPDATED. WE USED THE
MANY EMAILS AND DISCUSSION GROUP TOPICS THAT RESULTED FROM THE
APRIL 27 EMWIN TRANSITION UPDATE TO CREATE A LIST OF FREQUENTLY
ASKED QUESTIONS. AS WE RECEIVE ADDITIONAL QUESTIONS...WE WILL
ADD TO THE EMWIN FAQS THAT ARE LOCATED ON THE EMWIN HOME PAGE.
HERE IS A BRIEF RECAP...EMWIN IS NOW BROADCAST FROM GOES
/GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITE/ EAST AND WEST
SATELLITES. THE FINAL SATELLITE OF THE CURRENT SERIES /GOES-M/
IS SCHEDULED TO BE LAUNCHED IN JULY 2001. CURRENTLY...GOES-N IS
SCHEDULED FOR LAUNCH AND STORAGE IN ORBIT IN FEBRUARY 2003.
TRANSITION OF THE EMWIN BROADCAST TO GOES-N WILL NOT OCCUR UNTIL
SOMETIME BETWEEN 2003 AND 2005 /BARRING MULTIPLE CATASTROPHIC
SATELLITE FAILURES/.
EMWIN CAN NOT BE BROADCAST IN ITS CURRENT FORM ON THE GOES SERIES
N THROUGH Q. MAJOR DIFFERENCES ARE:
- THE NEW SERIES OF SATELLITES WILL BROADCAST A DIGITAL SIGNAL
RATHER THAN THE CURRENT ANALOG
- THE EMWIN SIGNAL WILL USE A DEDICATED TRANSPONDER RATHER THAN
SHARE A CHANNEL AS IS CURRENTLY DONE
- THE EMWIN SIGNAL WILL CONFORM TO INTERNATIONAL REGULATIONS FOR
POWER FLUX DENSITY RESULTING IN REDUCED EMWIN BROADCAST POWER
LEVELS...AND
- EMWIN BROADCAST FROM GOES-N THROUGH Q WILL REQUIRE DIFFERENT
MODULATION CHARACTERISTICS.
IN EARLY JUNE 2001...THE GOES-11 SPACECRAFT WAS TAKEN OUT OF
ON-ORBIT STORAGE TO PERFORM A SERIES OF TESTS SIMULATING THE
GOES-N ENVIRONMENT. THE TESTS CONFIRMED THE CURRENT SPACECRAFT
SERIES /GOES-I THRU M/ CAN SUPPORT ALTERNATIVE TRANSITION
SCENARIOS. THESE SCENARIOS INCLUDE OPERATING EITHER WEFAX OR
LOW-RATE INFORMATION TRANSMISSION /LRIT/ WITH EITHER THE CURRENT
EMWIN OR A SIMULATED /NOT AT THE FINAL GOES-N FREQUENCY/ GOES-N
EMWIN. THE WIDER CHOICE OF TRANSITION ALTERNATIVES MAY PROVIDE
THE OPPORTUNITY FOR A SIMULATED GOES-N EMWIN CHANNEL /DIGITAL...
BPSK WITH FORWARD ERROR CORRECTING CODING...BUT AT THE PRESENT
RECEIVER FREQUENCY/ BEFORE GOES-N BECOMES OPERATIONAL.
AN INEXPENSIVE CHIP SET INCORPORATING A FORM OF FORWARD ERROR
CORRECTION CALLED TURBO CODING HAS RECENTLY BECOME AVAILABLE. A
STUDY IS BEING CONDUCTED TO DETERMINE THE FEASIBILITY OF USING
TURBO CODING IN THE GOES-N EMWIN MODULATION. IF SUCCESSFUL...
THE NEW CHIP SET WOULD PROVIDE A LOW COST ALTERNATIVE TO THE CHIP
SET ORIGINALLY PROPOSED FOR A GOES-N EMWIN DEMODULATOR.
ADDITIONAL GOES-N THROUGH Q BROADCAST SIMULATIONS USING CURRENT
SATELLITES WILL BE CONDUCTED LATER THIS YEAR TO PROVIDE THE
TECHNICAL INFORMATION NECESSARY FOR THE DESIGN OF NEW DIGITAL
RECEIVER SYSTEMS.
ANSWERS TO MOST QUESTIONS RECEIVED AT THE EMAIL ADDRESS BELOW
WILL BE ADDED TO THE EMWIN FAQS ON THE EMWIN HOME PAGE:
EMWIN.SYSTEM@xxxxxxxx
THE COMPLETION OF THE EMWIN TRANSITION IMPLEMENTATION STUDY
PLANNED FOR EARLY JUNE 2001 IS NOW EXPECTED AT THE BEGINNING OF
AUGUST 2001. THE NEXT TRANSITION UPDATE MESSAGE IS PLANNED
SHORTLY AFTER THE STUDY/S COMPLETION.
END
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