June 16, 2000
All of us who are responsible for managing successful satellite
uplinks are reminded to be aware of possible "sun outages" which
may cause temporary interruptions in satellite transmission
services for periods of up to seven to eight minutes per day.
This natural phenomenon occurs in the Spring and Fall and can
affect both uplink and downlink ground stations. Interruptions
in service may occur when the satellite ground station, the
transmitting satellite and the sun are in complete alignment.
The time of day during which this alignment occurs for a particular
ground station is predicable.
If you have questions about a satellite transmission which you
have planned during these outage periods, and you are concerned
about possible interference during your transmission, you may
contact ADEC or you may call the appropriate satellite carrier
SATELLITES CARRIER TELEPHONE NUMBER
GALAXY & SBS PanAmSat (800) 321-3959
TELSTAR Loral Skynet (800) 242-2422
SPACENET & GE GTE Spacenet (800) 772-2363
ANIK Telesat Canada (800) 265 3074
The satellite carriers provide technical assistance on their
websites which may be helpful in determining if transmission
difficulties may be encountered. Some of the following sites
require the user to register (no cost) and/or to download operational
CARRIER SUN OUTAGE WEBSITE
(This site provides a detailed description of the causes of
GE Americom <http://www.geamericom.com/tools/license.html>
(Registration is required prior to accessing webpage)
Loral Skynet <http://www.loralskynet.com/tech_resources/tools_us.asp>
(Requires downloading of program)
In order to determine if transmission interference is probable,
you will need to provide the date and time of day for the transmission,
the name of the satellite you will be using and the location
of your satellite ground station.
SOLAR FLARES (Sun Spots):
Earth has experienced the effects of increased solar activity
since the occurrence of two AX-Class@ solar flares (the most powerful
class) on June 6th of this year. The geomagnetic storms resulting
from these solar disturbances sent ionized gas clouds and electromagnetic
energy towards earth at 1.6 million miles per hour. Solar activity
varies in intensity on an eleven year cycle and peaked this year.
The Space Environment Center in Boulder, Colorado, advised
that sunspot clusters could be active through June 24th.
Geomagnetic storms can adversely effect electric power grids,
disrupt terrestrial electronic telecommunications and cause
disorientation or failure of communications satellites. During
this period of maximum solar activity, ADEC recommends that
program providers which are using satellites check with the
satellite operator or with ADEC for information regarding the
effects of solar activity on transmission quality.