[Ips-hf-warning] ASWFC HF SHORTWAVE FADEOUT WARNING issued 0401 UT on 06 Jan 2023 [SEC=OFFICIAL]

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SUBJ: ASWFC HF RADIO COMMUNICATIONS WARNING 23/03
ISSUED AT 0355UT/06 JANUARY 2023
BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

Update of Shortwave Fadeout (SWF) Warning 23/01. 

Solar region AR3182 recently rotated onto the solar disk in the 
solar southeast quadrant and produced an R3 (X1.2) flare at 
06/0057UT. Further R3 events are now considered likely from this
solar region. Frequent HF shortwave fadeouts are now expected on 
daylight HF circuits. Isolated severe HF fadeouts may be experienced.

DEGRADED HF PROPAGATION CONDITIONS EXPECTED
FROM 06-08 JANUARY 2023
IF COMMS DIFFICULTIES EXPERIENCED TRY A HIGHER FREQUENCY BAND
_____________________________________________________________

SOLAR ACTIVITY FORECAST       HF COMMS FADEOUTS
06 Jan:  R1-R3                 Probable
07 Jan:  R1-R3                 Probable
08 Jan:  R1-R3                 Probable

Note:
An SWS MUF depression HF Warning and SWS shortwave fadeout 
HF Warning are both current. Shortwave fadeouts degrade 
lower shortwave radio frequencies first (through increased 
ionospheric absorption) and the usual strategy during shortwave 
fadeouts is to try a higher frequency. In contrast, during 
periods of ionospheric MUF depression, the upper frequencies 
are degraded first and the usual strategy is to use a 
lower frequency. 

In general use a lower frequency if you are having trouble
with your normal workable frequency.

If a shortwave fadeout occurs during a period when ionospheric 
MUFs are depressed the available HF bandwidth will be "squeezed", 
with increased absorption raising the lowest usable frequency 
and the ionospheric depression lowering the highest usable 
frequency. Under such conditions it is suggested that the 
HF communicator operates on the highest usable frequency, 
even though this may well be in fact lower than what is normally 
supported for that particular circuit.

Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au