ARLA/CLUSTER: Radio australiana em Onda Media é escutada numa vila de pescadores na Noruega, a 18 000 Km

[João Costa > CT1FBF]

Adelaide radio making waves 18,000 km away in Norway

AM radio waves can travel amazing distances: a signal broadcast from 891
ABC Adelaide’s Pimpala Transmitting Station at Reynella was received 18,000
kilometres away in the small seaside fishing village of Kongsfjord, Norway.

For the last 38 years Norwegian resident Arnstein Bue has been a keen radio
scanner.

Every October since 1997, Mr Bue has travelled to Kongsfjord at the
northern tip of Norway to scan the radio waves and learn about different
people and cultures.

Mr Bue is a member of a local group of DXers, radio monitors who focus on
capturing signals from afar.

The group use a 500-metre-antenna array with extremely sensitive receivers
to tune in to radio frequencies bouncing off Earth’s ionosphere.

“In September last year we experienced some pretty good conditions to
Australia and I head a few AM radio stations I had not heard before,� Mr
Bue explained. He has managed to capture several signals from around
Australia.

“One of the stations that pleased me a lot was 891 ABC Adelaide, which I
have been hunting for ever since I heard ABC Radio National on 729 AM 15
years earlier.�

He reported hearing the Adelaide-based radio station and another station,
believed to be broadcasting from Asia, on the same frequency.

Mr Bue and three other members of the Kongsfjord DXers have managed to
receive radio signals from around the globe, primarily focussing on AM
radio stations transmitting from North America and the Pacific.

Bouncing radio waves around the world:

The ability to receive an AM signal 18,000 kilometres from its origin is
very rare.

A signal bouncing off the ionosphere is called a skywave. Modern
transmitters are designed to reduce skywave signal, directing transmissions
more at a ground or surface level.

According to ABC senior transmission engineer Pawel Bochenek cloudy weather
and sun radiation also stop a signal from reaching atmospheric levels where
it is able to reflect.

"The angle of reflection from the ionosphere is equal to the angle of
attack," Mr Bochenek said.

"Taking into account the characteristics of the transmission antenna and
the curvature of the earth you can calculate where the first ground contact
will occur using simple trigonometry."

891 ABC Adelaide's transmitter outputs 50,000 watts of power into the
Reynella antenna system.

http://www.abc.net.au/news/2014-09-11/
adelaide-radio-making-waves-18000-km-away/5734132
<http://www.abc.net.au/news/2014-09-11/adelaide-radio-making-waves-18000-km-away/5734132>

Our thanks to *Mike Terry* for spotting this item
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