[Ips-hf-warning] SWS HF COMMS WARNING issued 2342 UT on 02 Feb 2022

[rwc]

SUBJ: SWS HF RADIO COMMUNICATIONS WARNING 22/12
ISSUED AT 2335UT/02 FEBRUARY 2022
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

STRONGLY DEPRESSED AND DEGRADED HF CONDITIONS FOR 
03 FEBRUARY ARE NOW NOT EXPECTED DUE TO WEAK OVRNIGHT
GEOMAGNETC ACTIVITY FOLLOWING AN ARRIVAL OF A CME.

AUSTRALIAN REGION MAXIMUM USABLE FREQUENCIES ARE EXPECTED
TO BE INIIALLY DEPRESSED BY APPROXIMATELY 15-20% TODAY, 
PARTICULARLY FOR SOUTHERN AUSTRALIAN REGION,THEN RECOVERING 
TO NEAR NORMAL LATER IN THE DAY.

DEGRADED HF PROPAGATION CONDITIONS EXPECTED
FOR FIRST HALF LOCAL DAY 03 FEBRUARY 2022
IF COMMS DIFFICULTIES EXPERIENCED TRY A LOWER FREQUENCY BAND
_____________________________________________________________

HF COMMUNICATIONS FORECAST (AUSTRALIAN/NEW ZEALAND REGION)
                                   FREQUENCY BANDS
       T-index      MUFs        2  4  6  8 12 16 22 26
_____________________________________________________________
03 Feb:   25   -20%/normal      2  4  6  8 12 12 16 22

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.

Space Weather Services              email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386                         WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240  AUSTRALIA       FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010                fax: +61 2 9213 8060 

IMPORTANT: This e-mail, including any attachments, may contain,
confidential or copyright information.  The views expressed in 
this message are those of the individual sender, unless 
specifically stated to be the views of SWS.  If you are not 
the intended recipient, please contact the sender immediately 
and delete all copies of this e-mail and attachments. 
To unsubscribe from an IPS mail list either send an email to 
"MAIL_LIST"-leave at ips.gov.au or go to
http://www.sws.bom.gov.au/mailman/listinfo/"MAIL_LIST".
Information about training can be obtained from
http://www.sws.bom.gov.au/mailman/listinfo/ips-training.
General information is available from
http://www.sws.bom.gov.au/mailman/listinfo/ips-info.