Radio Astronomy – A Brief History

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The Radio Astronomy section of the ASRAS website is under constant construction. So please be patient with us as we learn how to design effective web pages in WordPress.

Martin Pepe

A Brief History

Relevant Links: Karl Jansky, Grote Reber

In 1928 Karl Jansky started working on a long wire antenna for Bell Laboratories to create a transatlantic Radio Telephone Service to Europe using the 20.5 MHz band.

Results were erratic as they encountered a ‘hiss’ that repeated exactly every 23 hrs. & 56 min (NOT 24 hrs.). Furthermore, the baseline noise level, repeated & tracked each month in every year.

Unknowingly, they were receiving celestial radio emissions from planets, the Sun, stars, galaxies, etc. The reason for the 23 hrs. 56 min. repeat was that it is exactly how long it takes for the Earth to make one complete revolution (1 day) on its axis (not 24 hrs.).

Grote Reber – 1911 – 2002

Additionally, the baseline repeated each month of the year – their antenna was pointed out to a different location in deep sky (for the same reason you don’t see the constellation Orion in the summer & Scorpius in the winter), and they were also receiving synchrotron radiation from the cosmic ray background (CMB) .

A bright grad student and avid ham radio operator, Grote Reber wanted to join this team to continue this work. But alas, the project was canned & he was not hired. Undaunted, Grote built a dish antenna in his mother’s backyard of suburban Chicago, then added a chart recorder to give himself a hardcopy record of his experiments.

He had to switch to evening work, as there was too much interference (RFI) during the day from car ignitions and industry.

I’m sure he raised some suspicions from the neighbors & government as the year was 1943! But it helped to put Ham Radio research on the map during and after WW II.

Book – Cosmic Noise –  >>A History of early Radio Astronomy

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