Discovery of microwaves leads to development of radio telescopes

Some magnetrons were handed over to NRC, which improved them and incorporated them into radar systems for the allies

In 1940 Britain was hard pressed defending itself, and did not have the resources to exploit important secret devices it had invented for the war effort. The British government decided to hand them over to Canada and the U.S.A., where the resources were available to continue their development.

One of the most closely-guarded of these secrets resembled a copper hockey puck with cooling fins, with two wires coming out of one edge, with a large connector opposite. This device, the resonant cavity magnetron, invented by John Randall and Harry Boot at Birmingham University, made it possible, for the first time, to produce high-power radio transmissions at short, centimetre wavelengths. Today we call these microwaves. That copper hockey puck made precision radar systems possible, using antennas ten or more times smaller than any existing systems. They could be deployed on aircraft, vehicles and ships. Earlier airborne radars required the plane to be covered in antenna components, making them look like flying hedgehogs. The new antennas could be little dishes concealed in the noses of the aircraft.

Some magnetrons were handed over to NRC, which improved them and incorporated them into radar systems for the allies, making the organization a major centre for wartime radar development. When peace returned, NRC found itself with a lot of accumulated expertise and a lot of radar hardware lying around. One of the NRC scientists working on radar development was Arthur Covington. In 1946 he and his colleagues used those components to make Canada’s first radio telescope. Its operating wavelength was 10.7 cm.

Over the following months, Canada’s first radio astronomers pointed their instrument at the Milky Way, planets, the aurora, the Moon and the Sun. However, the only cosmic radio waves they could detect came from the Sun.

Covington and his team noticed two key things. Firstly the solar radio emissions were stronger than expected, and secondly, they varied from day to day. Using a solar eclipse on 23 November, 1946, Covington found that most of the radio emission was coming from a magnetically active area on the Sun, and that the measurements he and his team were making were a stethoscope on solar magnetic activity.  Fortuitously, 10.7 cm is a very good wavelength for this. Since this magnetic activity affects our communications, satellite performance, GPS navigation, power lines, pipelines and many other human activities and infrastructure elements, Covington’s radio measurements became very important, and a service of providing these data, now known as the 10.7 cm solar radio flux, or F10.7, to users around the world.  NRC, now in partnership with Natural Resources Canada and the Canadian Space Agency, continues to make daily measurements of F10.7 and distribute them to the world. The programme is now located at the Dominion Radio Astrophysical Observatory, in B.C.

In the postwar years, the resonant cavity magnetron made possible one other key piece of technology that most of us have in our homes, the microwave oven.

Mars is low in the Southwest after sunset. Jupiter rises around 7 p.m. and Venus around 4 a.m. The Moon will be new on the 13th.

Ken Tapping is an astronomer with the National Research Council’s Dominion Radio Astro-physical Observatory, Penticton.


Just Posted

A campaign encourages families to put down their phones and talk this Mother’s Day

OpenTable’s #DiningMode gets Okanagan restaurants on board with a no phone policy while dining

Okanagan experience for the Blue Man Group

The world tour of the Blue Man Group came to Penticton this week for two shows.

Olympian Andi Naude retires from freestyle skiing

Penticton native skied in 62 World Cup single and dual moguls events in her career

Syrup commercially produced from Summerland maple trees

Maple Roch produces 50 bottles of syrup after trees in the community were tapped

Photos: Saddle broncs and bullriders raise the dust in Similkameen

The 54th annual Chopaka Easter Jackpot Rodeo took place near Keremeos Sunday

VIDEO: Driver in bizarre hit-and-run at B.C. car dealership turns herself in

Police believe alcohol was a factor in incident causing estimated $15,000 in damages

‘B.C. cannot wait for action’: Top doctor urges province to decriminalize illicit drugs

Dr. Bonnie Henry says current approach in ‘war on drugs’ has criminalized and stigmatized drug users

B.C. woman, 76, challenges alcohol-screening laws after failing to give breath sample

Norma McLeod was unable to provide a sample because of her medical conditions

New report on 2017 wildfires calls for better coordination with B.C. First Nations

Tsilhqot’in National Government documents 2017 disaster and lists 33 calls to action

Okanagan experience for the Blue Man Group

The world tour of the Blue Man Group came to Penticton this week for two shows.

B.C. youth coach banned amid sexual harassment, bullying scandal: Water Polo Canada

Justin Mitchell can’t take part in Water Polo Canada events or clubs

Wilson-Raybould: Feds want to just ‘manage the problem’ of Indigenous Peoples

Former federal justice minister speaks at First Nations Justice Council meeting in B.C.

Okanagan College names new fundraising director

Helen Jackman will join the college as executive director of the Okanagan College Foundation and director of advancement

Most Read