Sunday, October 27, 2013

NOAA Weather Transmitter Causing Interference

According to this release from NOAA, the New York City area weather transmitter seems to be causing some interference issues with the Coast Guard:

NOUS41 KOKX 041949
PNSOKX
CTZ005>012-NJZ002-004-006-103>108-NYZ067>075-078>081-176>179-092100-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE NEW YORK NY
345 PM EDT FRI OCT 4 2013

...NOAA WEATHER RADIO NEW YORK CITY REMAINS OUT OF SERVICE...

THE NOAA WEATHER RADIO TRANSMITTER THAT SERVES THE NEW YORK CITY
METROPOLITAN AREA HAS BEEN CAUSING RADIO FREQUENCY INTERFERENCE ON
THE U.S. COAST GUARD CHANNEL 16 TRANSMITTER FOR INTERNATIONAL
DISTRESS...SAFETY AND CALLING SINCE LATE JULY.

THE NEW YORK CITY TRANSMITTER BROADCASTS ON A FREQUENCY OF 162.550
MHZ AND THE U.S.COAST GUARD TRANSMITTER BROADCASTS ON A FREQUENCY OF
156.800 MHZ. OTHER TRANSMITTERS...IN VERY CLOSE PROXIMITY TO THE NYC
TRANSMITTER BROADCAST ON A FREQUENCY OF 168.3 MHZ.

THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT
AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. WE HAVE
INSTALLED A FILTER ON THE NYC TRANSMITTER...WHICH REDUCED...BUT DID
NOT ELIMINATE THIS PROBLEM. WE WORKED WITH ANOTHER FEDERAL AGENCY
AND OVERSAW THE INSTALLATION OF ANOTHER FILTER...ON A TRANSMITTER
BROADCASTING OVER 168.3 MHZ...WHICH DID NOT FURTHER REDUCE THE RADIO
FREQUENCY INTERFERENCE.

WE CONTINUE TO WORK WITH THE U.S. COAST GUARD TO RESOLVE THIS
PROBLEM AND APOLOGIZE FOR THE INTERRUPTION OF OUR ROUTINE WEATHER
BROADCASTS.


...NOAA WEATHER RADIO WILL BE PLACED IN OPERATION TO BROADCAST 
SHORT FUSE LIFE THREATENING WEATHER WATCHES AND WARNINGS...

NOTE THAT THE NYC TRANSMITTER WILL BE PLACED IN OPERATION FOR THE
ISSUANCE OF SHORT FUSE LIFE THREATENING WEATHER WATCHES AND
WARNINGS...SUCH AS TORNADO...SEVERE THUNDERSTORM AND FLASH FLOOD
WATCHES AND WARNINGS...TO ENSURE DISSEMINATION THROUGH THE EMERGENCY
ALERT SYSTEM...WHICH IS CARRIED BY THE BROADCAST MEDIA.

THANKS FOR YOUR PATIENCE AND FOR LISTENING TO NOAA WEATHER RADIO.

WE WILL PERIODICALLY PROVIDE YOU WITH UPDATES ON THE STATUS OF THE
NEW YORK CITY NOAA WEATHER RADIO TRANSMITTER VIA THESE PUBLIC
INFORMATION STATEMENTS.

$$
GC

The 168.3000 MHz transmitter mentioned in this release is an FBI P25 repeater. It appears that the mixing between the FBI repeater and the NWS broadcasts are causing interference issues on marine channel 16. Various filtering solutions have apparently not solved the problem.