ARLA/CLUSTER: África do Sul chama a atenção para contactos por "Tropo Scatter" em VHF

João Costa > CT1FBF ct1fbf gmail.com
Segunda-Feira, 8 de Maio de 2017 - 13:17:35 WEST


Tropo Scatter communications

Tropo Scatter could provide almost daily contacts countrywide on VHF.
Propagation via the Tropo Scatter mode is possible almost daily across most
of South Africa.

Tropo Scatter is not weather related, unlike Tropo Enhancement and Tropo
Ducting, but is caused by dust particles, moisture and turbulence in the
atmosphere.

Unfortunately, Tropo Scatter communication comes at a price of running 400
up to 1 000 Watts of power with high gain horizontal Yagi beam antennae and
sensitive receivers.
The advantage is reliable communications daily on VHF and UHF over
distances up to 1 000 km, while the disadvantage is signals of low level
and deep QSB cycles.

Diversity reception and computer correction has been successfully applied
to commercial and military communications to provide constant signals. The
144 and 432 MHz bands could be the most practical for radio amateurs
beaming just above the horizon.
It only requires a few dedicated and well-equipped amateurs to explore this
type of propagation and they could also use EME equipment.
Division 4 is centrally situated and could become the hub of this type of
activity in South Africa.

The South African Radio League <http://www.sarl.org.za/Default.asp>
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