July 1957 Radio & TV News
 [Table
of Contents]
Wax nostalgic about and learn from the history of early
electronics. See articles from
Radio & Television News, published 1919-1959. All copyrights hereby
acknowledged.
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Sunspot cycles repeat approximately
every 11 years, so there had only been six solar maximums from the beginning of
long distance radio communications (Marconi in 1901) up until this article was published
in 1957. That year ('57) had the sun experiencing an extremely high number of sunspots
(see chart below), as had the previous few years, which caused communications to
be profoundly affected during the period. Under ideal conditions, high energy electrons
typically ejected from the sun (coronal mass ejection, CME) cause the Earth's ionosphere
to become an excellent reflector of RF energy at certain wavelengths, resulting
in phenomenal long distance contacts. Under the worst conditions, extreme levels
of "noise" are injected into radio signals, thereby severely degrading or even eliminating
communications. This story reports on a comprehensive study on the effect of such
activity on long distance communications, ultimately disproving the claims of many
that no good ever comes of solar flare activity. Fortunately - or not according
to this article from Radio & TV News - for Marconi, sunspot activity
was at a minimum when he made his first successful transatlantic transmission in
1901.
Sunspots Aid Radio Signals
John H. Nelson, radio weatherman, studies sunspot activity at
skyscraper observatory.
Radio weather forecasts improve the reliability of overseas circuits.
Results of a 10-year study of solar radio disturbances released recently by John
H. Nelson, of RCA Communications, Inc., relegated to the scrap-heap the popular
belief that sunspots are always bad for overseas radio communications. Of course,
severe sunspot activity can cause sudden ionospheric disturbances that may result
in poor or no signals, but by knowing in advance possible sunspot activity, it is
possible to maintain reliable service. This usually involves an increase in operating
frequency to prevent signal loss. At the same time it is possible to even reduce
operating power.
Radio hams and TV DX-er's have long known that during periods of peak sunspot
activity, such as exists at the present time, some very long distance contacts may
be made. RCA Communications is taking advantage of this knowledge, coupled with
Mr. Nelson's observations and forecasts, to maintain reliable radio contact with
its overseas stations. Ordinarily, the bulk of such traffic is carried on 13 or
14 mc. or lower. When Mr. Nelson gives the word, the frequencies are shifted upward
to 18 to 24 mc.
The National Bureau of Standards also supplies, over station WWV, a continuous
forecast of ionospheric conditions. These forecasts, however, are only for some
6 hours in advance while the forecasts used by RCA are for 30 hours in advance.
These latter forecasts are also unique in that they take into account the positions
of the various planets since Mr. Nelson believes these have an influence on radio
conditions.
Posted June 22, 2021
(updated from original post on 10/10/2014)
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