[Ips-hf-warning] IPS HF COMMS WARNING

[rwc]

SUBJ: IPS HF RADIO COMMUNICATIONS WARNING 02/72
ISSUED AT 22/0125Z NOVEMBER 2002
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

GEOMAGNETIC ACTIVITY WAS OBSERVED OVERNIGHT.
REGIONAL IONOSPHERE IS VARAIBLE.

STRANGELY NORTHERN AUSTRALIAN REGION MUFS HAVE
BEEN DEPRESSED 30-40% SO FAR TODAY, WHILST SOUTHERN
AUS/NZ MUFS HAVE BEEN ENHANCED BY UP TO 30%.  SOUTHERN
AUS REGION (HIGHER LATITUDE) STATIONS ARE NORMALLY MORE
LIKELY TO HAVE A DEPRESSION RESPONSE FOLLOWING GEOMAGNETIC 
ACTIVITY.

DEPRESSIONS HAVE BEEN OBSERVED AT PORT MORESBY DARWIN AND
TOWNSVILLE. MUNDARING IN WA APPEARS TO BE THE ONLY
SOUTHERN STATION SHOWING A DEPRESSION. WHILST LEARMONTH
APPEARS TO BE THE ONLY NORTHERN STATION NOT SHOWING A
DEPRESSION RESPONSE.

SOUTHERN REGION AUS/NZ COMMUNICATORS SHOULD USE A T OF 130
AS SOUTHERN REGION MUFS ARE CURRENTLY 30-40% ABOVE MONTHLY
PREDICTED VALUES.


DEGRADED HF PROPAGATION CONDITIONS EXPECTED FOR 22 NOVEMBER 2002
IF COMMS DIFFICULTIES EXPERIENCED TRY A LOWER FREQUENCY BAND.
-------------------------------------------------------------
SOLAR ACTIVITY FORECAST       HF COMMS FADEOUTS             
22 Nov:  Low to moderate      Possible             

HF COMMUNICATIONS FORECAST (NORTHERN AUSTRALIAN/PNG REGION ONLY)
                                   FREQUENCY BANDS  
       T-index  MUFs          2  4  6  8 12 16 22 26
-------------------------------------------------------------
22 Nov   10    -30%           2  4  6  6  8 12 16 16 

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