BendixKing KHF 990 - Manual (Page 163)

siderable difficulty getting through. With few exceptions, the higher
the solar flux and the lower the A and K index values (level of geo-
magnetic disturbance), the better HF propagation conditions should
be and vice-versa.
See Appendix A fo r more information on the format of geophysical
alert broadcasts and a glossary of related terms. Incidentally, prior to
September 30, 1976, radio propagation forecasts useful to an HF
user were broadcast on WWV. Some of this information is in geo-
physical alert announcements, but no forecasts of the actual frequen-
cies you should use is available on a broadcast at this time.
OMEGA NAVIGATION SYSTEM STATUS REPORTS
WWV and WWVH also broadcast status reports on the Omega
Navigation System. The Omega System is a very low frequency navi-
gation aid operating in the 10 to 14 kHz frequency band. These
broadcasts are in voice from WWV at 16 minutes after the hour and
from WWVH at 47 minutes after the hour. Eight Omega stations are
in operation around the world. Omega signals are subject to degrada-
tion caused by ionospheric disturbances at high latitudes. The
Omega announcements on WWV and WWVH are given to provide
users with immediate notification of such events and other informa-
tion on the status of the Omega system.
GLOBAL POSITIONING SYSTEM (GPS) STATUS
ANNOUNCEMENT
Since March 1990 the U.S. Coast Guard has sponsored two voice
announcements per hour on WWV and WWVH, giving current status
information about the GPS satellites and related operations. The 45-s
announcements begin at 14 and 15 minutes after each hour on WWV
ant at 43 and 44 minutes after each hour in WWVH. For further infor-
mation, contact the Commanding Officer, U.S. Coast Guard Center,
7323 Telegraph Road, Alexandria, VA 22310-3998.
MARINE STORM WARNINGS
Weather information about major storms in the Atlantic and Eastern
North Pacific is broadcast on WWV at 8, 9 and 10 minutes past each
hour. Similar storm warnings on the Eastern and Central North pacific
are given from WWVH at 48, 49 and 50 minutes after each hour. An
additional segment (at 11 minutes after the hour on WWV and at 51
minutes on WWVH) may be used when there are unusually wide-
spread storm conditions.
Services
8-5 KHF 950/990 Pilots Guide
Rev. 0
Dec/96