Tropospheric and line of sight
) is the scattering of distant
stations by the troposphere
so that they
travel farther than the line
. This effect sometimes allows reception of stations up
to a hundred miles away.
The phenomenon has been used to build communication links in a
number of parts of the world. Large billboard antennas
focus a high power
radio beam at the troposphere mid-way between the transmitter and
receiver. A certain proportion of the signal is refracted and
received at a similar antenna at the receiving station.
link operated between the North of Scotland, at Mormond Hill and the Shetland Isles.
US Army TRC-170 Tropo Scatter
The U.S. Army uses tactical tropospheric scatter systems developed
for long haul communications.
The systems come in two configurations, the original "heavy tropo",
and a newer "light tropo" configuration exist. The systems provide
group channels and
trunk encryption, and 16 or 32 local analog phone extensions.
The U.S. Marine Corps also uses the same device, albeit an older