Amateur Radio Astronomy
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.
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. 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.
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).
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.
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.
Earth (Planetary) Noises
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.
A traditional area of amateur radio is electronics. To understand electronics, one must learn about electricity, analogue electronics, digital electronics and so forth. This is an applied science and one quick learns about soldering technique, electrostatic discharge and good laboratory techniques. All of these things can either make or break the performance of radio communications equipment.
Technology changes over the years and amateur radio operators have to change with it. Some amateurs modify their equipment to make it perform better. Quite often we must design and build our own equipment because it is better performing or significantly cheaper than equipment purchased on the market. Radio Direction Finding kits, keyer kits, transceiver kits - these are just some of the equipment that we build - not necessarily from scratch. One of the skills we acquire is being able to salvage components from discarded electronics. Being able to use these and incorporate them into a working device is a skill - and it is an old survival skill. What happens when one's radio breaks or a commercial antenna snaps off? Many persons would be astonished that an apparent piece of junk can be transformed into a high performing electrical device. For amateur radio operators, we "jury rig".
High Altitude Balloons
Although such activity is still in very early planning stages for YARS, a number of amateur radio groups have been conducting experiments by launching high altitude balloons into the stratosphere. Typically they attach video cameras, a beacon transmitter, sensors and automatic position reporting system (APRS) and then track the balloon as it ascends and then falls back to Earth. These experiments are quite popular in the United States and in Canada.
- Alberta Balloon Experiments with Amateur Radio
- Amateur Satellite Organization (AMSAT)
- YouTube Experimental Balloon Ascent KJ4IES
Linux and Computers
Since the 1990s the fields of radio and computers have converged. Many radios can be operated with computer aided control, logging and even anaysis of signals. With convergence, most amateur radio stations have the capability of radio teletype and other digital communications that, only fifteen years ago, were within the capabilities of large telecommunications companies, government organizations or militaries.
YARS has an active group of amateurs experimenting with Linux, an alternative operating system to Windows or the MacIntosh. True to our hobby, experimentation and the recycling of old equipment is facilitated. Computers that are obsolete are routinely given a new lease on life.
Many of the skills developed through experimentation have application in daily life or at work. Whether it is programming, learning how to set up and maintain a website, using desktop publishing software or hooking up a radio to a computer controller.
Amateur radio may well be your grandfather's hobby, but it exists in our technological time.
Satellites, EME, Meteor Scatter and Weak Signal Modes
The North presents a number of challenges for HF operations however there are alternatives.
- Satellites - The amateur radio service does have its own satellites (about 400 in number) in orbit around Earth - some of which work reliably, others that are intermittent and some that do not work at all. Many of these are very small satellites. They carry on board beacons, telemetry devices and in some cases repeaters (VHF/UHF/HF). There are computer programs to track these satellites and one can easily point a directional antenna to the sky where they are found to listen in. Interesting effects occur that are very well studied including doppler shifting in frequency. The modes are all low power (< 5 Watts). We have reached Manitoba, Alberta, Washington State and even California from Yellowknife via satellite. Of course one only has 4 minutes typically. There are offshoots from the amateur satellite projects including AMSAT, the ARISS program (which allows amateurs to speak to the ISS with school students) and the development of the FunCube Dongle (a type of SDR). Educationally this is a great way to gain exposure to space science and space technology. In terms of tracking, one can experiment with robotics and track satellite passes and learn about the tidal effects on satellites and spacecraft.
- EME - Earth-Moon-Earth - Probably the ultimate in satellite communications using the largest satellite of the Earth. While the moon moves slower and its doppler shift is less pronounced, it poses other challenges. The surface of the moon may reflect light and radio waves but its surface is uneven and signals tend to be attenuated by our atmosphere and dispersed by the surface of the moon (albedo). To compensate high gain antenna arrays and high power are needed. The benefit of this method is that there is potentially a reliable satellite in the sky for nearly half a day (moonrise to moonset). Since the signals coming back are weak, methods of detecting faint signals need to be used.
- Meteor Scatter - Meteor scatter techniques can be sophisticate or not. When a meteor burns up in the atmosphere it leaves an ionized trail. Radio signals can bound off that trail. It is possible to hear distant FM stations during a meteor shower and that technique is actually used to measure the storm's intensity. For amateur radio it is possible to send bursts of signals over time and thereby eventually pass message traffic. This was a viable commercial method of radio communications before the advent of satellites. With programs such as WSJT this method is within the grasp of an amateur radio operator - even one who can only operate on VHF.
- Weak Signals - YARS has recently been investigating some of the techniques available to the amateur radio community and has made hundreds of contacts in 2014 using JT-65 and JT-9 as well as Olivia. These are advanced digital modes that make use of significant forward error correction and statistical averaging to pull very weak signals out of the noise. Nearly all of our JT-65 and JT-9 contacts were made using 5 Watts (QRP). JT-65 and JT-9 first appeared in WSJT software. YARS notes in particular the support from Nobel Laureate and American astrophysicist, Joe Taylor, K1JT, in making this software freely available to the amateur radio service (we also note that it was amateur radio that propelled Joe Taylor into astrophysics). WSJT software also facilitates meteor scatter and one of these days we hope to actually get that mode operational. JT-65 is not generally used during contests such as Field Day, however we can use it to test antenna reception and directivity and band conditions. As of January 2015, JT-65 is YARS' third most used mode (SSB being first followed by PSK31) and stations contacted on all continents. Because of the forward error correction JT-65 is robust, economical on power and seems to get through even when the bands are marginal for use.