ARLA/CLUSTER: Como um radioamador descobriu a propagação troposferica.

[João Costa > CT1FBF]

How did Ross A. Hull, VK3JU, discover tropo propagation?

Ross A. Hull, VK3JU, ex-editor of Wireless Weekly, emigrated from
Australia to the USA where he joined the staff of the ARRL and became
Associate Editor of QST magazine.

As a foreigner he was not allowed by US law to apply for an amateur
radio licence, but as a member of the ARRL headquarters staff he could
operate under their call sign.

He developed new equipment for the ARRL and produced many
constructional articles for the early ARRL Radio Handbooks, and showed
a particular interest in the "Ultra High Frequency" (UHF) 5 metre (56
- 60 MHz) band.

At the time all the experts believed that the "UHF" spectrum above 30
MHz were only suitable for short distance line-of-sight
communications, but in 1934 Ross Hull proved them wrong. He was
resident at West Hartford, Connectcut, and decided to conduct some
tests on 60 MHz with amateurs in Boston, Massachusetts, about 160 km
away.

At first the Boston amateurs did not hear anything at all until Ross
changed his vertical antenna to a beam consisting of four quarter wave
radiators fed in phase with four reflectors. Signals varied from
morning to afternoon or day to day from weak to very strong. Ross soon
realized that this phenomena was weather related and caused by
temperature inversions; he discovered refraction of VHF radio waves in
the troposphere!

Soon other amateurs started using beams on 5 metres too and extended
the range to 500 km.

Unfortunately Ross Hull came to a sudden and sad end when he reached
for a switch underneath his desk, and touched the 6 000 Volt contact
of the transformer supplying power to his cathode ray TV tube; he died
instantly.

Source: The South African Radio League