Special BBC Broadcast
During a total solar
eclipse an eerie quiet envelopes the landscape inside the path of
totality as day becomes night for a few minutes. However, from
the unique perspective of a ham radio operator, night is anything
but quiet - and neither is a solar eclipse. Many shortwave radio
stations that are undetectable in daytime are easy to pick up at
night. The reason has to do with the Sun's effect on Earth's
atmosphere.
During the day the "D layer" of Earth's ionosphere
absorbs shortwave broadcasts at frequencies below about 20 MHz.
At night the D layer vanishes and radio transmissions can
propagate long distances around the globe.
Scientists think that the same thing happens during a total
eclipse. When the Moon's shadow slices across the landscape, the
D layer above the path of totality vanishes. Radio signals that
moments earlier had no place to go are suddenly able to skip
across the globe. To test this theory, the UK's Merlin
Communications is teaming up with Science@NASA to conduct a special broadcast of the BBC
World Service
during the eclipse. The 7325 kHz signal will be transmitted from Rampisham, England, near the path
of totality.
Normally, the daytime signal would be barely detectable from the
NASA/Marshall Space Flight Center in Alabama, but during the
eclipse it may come in loud and clear. You can monitor the
signal, too, by returning here for a live audio webcast.
Live
Audio Webcast Schedule
Book mark this page and return for audio webcasts from the
Rampisham, England transmitter at the following times:
Calling
all Hams!!
If you have a shortwave radio and would like to assist NASA with
the audio eclipse atmospheric research program, please see Calling All Solar Disk Jockies for more information.
