WEBSITE OF THE YELLOWKNIFE AMATEUR RADIO SOCIETY

Yellowknife, Northwest Territories, CANADA

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When one thinks of astronomy one rarely thinks of amateur radio.  Yet consider the electromagnetic spectrum - only a very small portion of that is visible light.  Traditional optical telescopes only look at a small portion of the universe using visible light. 

Accidental Discovery of the Black Hole at the Centre of the Milky Way

The Milky Way - At its Centre is a Very Strong Radio Source Believed to be a Black Hole

An electrical engineer named Karl Jansky carried some experiments into the propagation of shortwave radio signals in 1931 while working at Bell Labs.  Through his observations of static he managed to detect a radio source that seemed to move depending on the day.  Quickly he discovered that this radio source was extra-terrestrial and was in fact located in the constellation of Sagittarius in an area known as Sagittarius A - the supermassive black hole at the centre of our own galaxy, the Milky Way.  Amateur radio was born by accident - a serendipitous discovery.

Yet black holes are not the only radio sources in the universe.  In the 1950s radio telescopes resulted in the discovery of quasars.  Closer to home the Sun was discovered to be an important radio source by accident during World War II when radar was being developed by the Allies.  Observation of solar emissions can be used to predict solar activity - which results in solar storms and geomagnetic storms.  Such storms can result in radio blackouts, aurora and confused migrating birds. 

Jovian Aurora as Viewed by Hubbel 2016

The planet Jupiter is a radio source and when Comet Shoemaker Levy was captured by its gravity and collided with the planet, this was observed via radio.  Jupiter even has its own Jovian aurora, and that can be observed on the HF band here on Earth.  NASA even has an educational outreach project on this subject, including a kit (Radio Jove).  Amateur radio equipment is already capable of detecting these transmissions. The Jovian aurora interacts with aurora on some of Jupiter's moons.

Arrow 2m 70cm Satellite Antenna for Field Day 2015 Hay River

Although not strictly astronomy, amateur radio satellite communications requires a basic understanding of tidal forces and the effects of solar particles on satellites.  Since one has to track satellites, a certain understanding of Keplerian motion needs to be obtained.  Early satellites such as Sputnik were first observed by amateur radio operators.  Radio amateurs have observed variations of tone from satellite beacons to calculate information about the rate of tumble of satellites as they fall into the atmosphere and burn up.  Some radio amateurs also try to intercept transmissions from deep space probes such as Pioneer and Voyager (source:  http://en.wikipedia.org/wiki/Voyager_1; VE8EV's detection of NanoSail-D in 2010 at http://ve8ev.blogspot.ca/search/label/6m%2FEME%2FSatellite).

Radios can be used to observe astronomical effects - for example check out meteor scatter propagation mode on this site.

Aurora Borealis

Different forms of the aurora borealis

The aurora borealis (aurora australis in the southern hemisphere) is caused by the interaction of charged solar particles with the magnetic field of the Earth and the atoms of the gases in the Earth's upper atmosphere.  The charged particles and field energize the atmospheric atoms of nitrogen and oxygen to make them glow.  This is exactly how a neon lamp works.  The aurora is the fourth state of matter - plasma.

For Yellowknife, the aurora is very important as there is a tourism industry based on it.  Astronomy North and the Canadian Space Agency maintain observations of the aurora through a program called AuroraMax

For amateur radio operators in the North, the aurora has a profound effect on radio propagation throughout the year.  At times it may make propagation very difficult, it may make the effects of auroral "flutter" pronounced or it may make propagation very good. Quite often when there is a strong aurora over the south, we can make distant contacts under the auroral oval with European and Asiatic Russia, Scandinavia, Nunavut and the United Kingdom.

Earth (Planetary) Noises

VLF Spectrogram of Electromagnetic Chorus Recorded at Palmer Station, Antarctica

Radio sources need not be extra-terrestrial.  The aurora may have its origins from the sun but it is terrestrial for it is the interaction of solar particles with the planetary geomagnetic field.  There are however other noise phenomenon that may be heard on radios - such as the Dawn Chorus.  The spectrogram above shows a sampling of this.  NASA has a recent satellite observation of this pheonomenon available at YouTube - Dawn Chorus.  The radio emissions are generated in the Earth's radiation belts - the zone around the Earth that protects us from solar radiation.  The aurora is probably related.  While this is all very ephemeral, it has practical concerns for the safety of astronauts and satellites.

There are other planetary radio emissions -  VLF noises.  A collection of these in .wav format may be found at S.P. McGreevy's website.  The manner in which these emissions arise is not entirely well understood. 

Meteors

Image from ukmeteorbeacon.org of a meteor echo

Here is an interesting video about Detecting Meteors with Software Defined Radio.  There is an active project in the UK on this:  https://ukmeteorbeacon.org/Home .  There is a gallery on that website showing spectrographs of the meteor reflections of a 6 m beacon. 

The equipment is very minimal - one needs just a software defined radio (SDR) and an antenna.  SDR RTL receivers are very cheap and simply plug into one's USB port.  While the UK beacon mentioned is probably a bit far for the NWT, other stations and beacons could be used.  One could also go up to the FM broadcast bands to do this with FM stations. 

The image above is from the website mentioned.  The sloping trails are of relatively long duration (30 seconds according to the scale) and are aircraft reflections.  From our work with amateur radio satellites they are probably a function of the velocity of the aircraft (remember velocity is a vector and includes speed and direction) - and what we see is a Doppler shift. The blue shift and red shifting are evident.  The slope is probably an indication of speed.  The direction from the receiver could be determined with a directional antenna. This is of course the principle behind radio detection and ranging - in effect: RADAR! 

The meteor signals are of short duration (seconds) and are effectively the horizontal blur.  This is because the meteor ionizes the atmosphere as it enters and burns up.  See also our  Meteor Scatter page.

Project Jove

Project Jove is a NASA-run project that is over 20 years old.  It has evolved over the years.  It is aimed at high school students in order to promote Science, Technology, Engineering and Mathematics (STEM).  It is primarily aimed at observing the coupling of the auroral activity of Jupiter with some of its moons (Io and Europa).  It can also be used to observe radio emissions of the Sun and galaxy.  The project involves construction of a real radio telescope observatory, collecting the data and sharing it around the world.  At one time a 10 m receiver had to be build but now a software defined radio (SDR) is now used.  The antenna still needs to be built.  A video of the project is at:  https://youtu.be/L5KL0DZJOYw .

Conclusion

Amateur radio astronomy is an interesting bridge between amateur radio and the hobby of astronomy.  Both are firmly rooted in the science of physics.  Although one does not need a licence to observe, the technical basics of knowing how to use the tools of observation may be of great use in knowing how to observe and understanding what it is that one is observing.  Astronomers after all should know about their telescopes, how they function and what their limitations are.

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