[Ips-hf-warning] IPS HF SWF COMMS WARNING issued 0042 UT on 28 Aug 2015

rwc rwc at ips.gov.au
Fri Aug 28 10:42:04 EST 2015


SUBJ: IPS HF RADIO COMMUNICATIONS WARNING 15/43
ISSUED AT 0042UT/28 AUGUST 2015
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

Active region 2403 (S15W57) that is approaching the west limb 
and produced a M2.9 flare on 27Aug is declining in size and magnetic 
complexity, but still has the potential for further M-class flares 
over the next 24 hours.

DEGRADED HF PROPAGATION CONDITIONS EXPECTED
FOR 28 AUGUST 2015
IF COMMS DIFFICULTIES EXPERIENCED TRY A HIGHER FREQUENCY BAND
_____________________________________________________________

SOLAR ACTIVITY FORECAST       HF COMMS FADEOUTS
28 Aug:  Low to moderate      Possible

Note:
An IPS MUF depression HF Warning and IPS 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 ips.gov.au
Bureau of Meteorology
PO Box 1386                         WWW: http://www.ips.gov.au
Haymarket NSW 1240  AUSTRALIA       FTP: ftp://ftp.ips.gov.au 
tel: +61 2 9213 8010                fax: +61 2 9213 8060 

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