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<DIV><FONT face=Arial size=4><STRONG>As condições de progação ionosférica,estão
de mal a pior (faz várias semanas):</STRONG></FONT></DIV>
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<DIV><FONT face=Arial size=2><FONT face="Times New Roman" size=3><STRONG><FONT
color=#ff0000 size=4><U>HF Fadeout Warning</U></FONT> </STRONG></FONT><FONT
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<TD vAlign=center width="10%"><FONT face="Times New Roman"><IMG
src="http://www.ips.gov.au/Images/HF%20Systems/Global%20HF/HF%20Conditions/ico_HFFadeoutWarning.gif"></FONT></TD>
<TD vAlign=center width="90%">Last updated 01 Jan 2008 11:00
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<TD colSpan=2><PRE>SUBJ: IPS HF RADIO COMMUNICATIONS WARNING 07/48
ISSUED AT 31/0128Z DECEMBER 2007
BY THE AUSTRALIAN SPACE FORECAST CENTRE.
HF COMMS FADEOUTS EXPECTED DURING DAYLIGHT HOURS
FROM 31 DECEMBER 2007 TO 02 JANUARY 2008
IF COMMS DIFFICULTIES EXPERIENCED TRY A HIGHER FREQUENCY BAND
_____________________________________________________________
SOLAR ACTIVITY FORECAST HF COMMS FADEOUTS
31 Dec: Low Possible
01 Jan: Low Possible
02 Jan: Low 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.
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<DIV><FONT face=Arial size=2><FONT face="Times New Roman" color=#ff0000
size=4><STRONG><U>HF Communications Warning </U></STRONG></FONT><FONT
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<TD vAlign=center width="10%"><FONT face="Times New Roman"><IMG
src="http://www.ips.gov.au/Images/HF%20Systems/Australasia/HF%20Conditions/ico_HFWarning.gif"></FONT></TD>
<TD vAlign=center width="90%">Last updated 01 Jan 2008 11:00
UT</TD></TR>
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<TD colSpan=2><PRE>SUBJ: IPS HF RADIO COMMUNICATIONS WARNING 07/47
ISSUED AT 29/2332Z DECEMBER 2007
BY THE AUSTRALIAN SPACE FORECAST CENTRE.
DEGRADED HF PROPAGATION CONDITIONS EXPECTED FROM
30 DECEMBER 2007 TO 01 JANUARY 2008 DUE TO LOW SOLAR ACTIVITY
Depressions of 15-30% continued to be observed at times
over the Aus/NZ region during the past 24 hours and are
again expected at times over the next few days.
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
_____________________________________________________________
30 Dec -40 -20%/normal 2 4 6 8 8 12 16 16
31 Dec -40 -20%/normal 2 4 6 8 8 12 16 16
1 Jan -40 -20%/normal 2 4 6 8 8 12 16 16
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