Amateur Radio Astronomy:   Problems, Opportunities, Suggestions

This page reviews some issues and opportunities having to do with amateur radio astronomy in general, not just meteor observing. Links to relevant sites and a short list of literature are included. The MITROS section includes a collection of all links referenced by this site.

Unlike the optical astronomer who has access to an enormous selection of pre-built professional grade equipment off-the-shelf, the independent radio astronomer must assemble most of his own apparatus, usually from scratch, at great effort and with much application of arcane expertise. Triumphs are hard-won. If you aren't up to this, you should consider doing something else altogether. It is enormous fun, however, if coming to grips with a difficult subject and enduring deferred gratification are your idea of amusement. Lately, however, some excellent equipment has become commercially available and you will find references in later links. Even so, the technical challenges are considerable.

Radio Astronomy (RA) is the science of exploring the Universe at wavelengths longer than those of visible light. We call these "radio" waves although, in fact, radio and light are the same thing apart from their photon frequencies. 

Significant achievements in radio astronomy of the type usually associated with deep-space observation are beyond the resources available to most who do not have access to a university, government or other professional radio observatory. Projects such as mapping galactic structure, searching for pulsars, identifying molecular spectral lines, SETI and so forth require facilities on a scale few individuals can afford or, especially, find the room for.   While there's no overestimating what ingenuity can accomplish, and some individuals certainly have what it takes (as you will find if you become a member of SARA, for example), ignoring the challenges would be foolish.

Nature of The Problem:

• Even to begin doing serious RA as in the highlighted examples above requires equipment working at very short wavelengths (where design and construction are especially challenging) with very weak signals submerged in noise. You will need an antenna half-power beamwidth of 4 degrees or less to obtain meaningful resolution.
  
  
  That means an antenna effective aperture of at least 3 meters (a 9 ft. parabola or "dish") at around 1.4 GHz and you really need 4 meters to get started. The bigger the better is the rule here. Putting up an 8 meter dish (providing a serious observing instrument) would be equivalent to erecting a small house.
  
  
• The antenna will require a guidance and tracking system (unless drift scanning is acceptable) able to operate precisely while managing the weight of the antenna and dealing with wind-loading - a considerable engineering challenge.
  
  
• There are some good alternatives to a dish (such as the helical antenna array) which might prove mechanically more convenient in certain cases but they are still going to be big for serious work and construction challenges are daunting. The laws of physics can't be avoided. Size matters. The signals are weak, the noise is strong. You have to capture the photons to do meaningful work.
  
  
• While suitable low noise electronics are now available at a reasonable cost, construction, calibration and maintenance require a dedication to precision and the acquisition of expertise few will want to aspire to (although for some, that's most of the fun and the effort is its own reward) or have the time for.
  
  
• What this boils down to is that interesting, educational demonstrations of principle and routine observations of brighter celestial radio objects already examined in detail by the "pros" are quite possible with modest equipment (let's say a standard 3 meter TVRO dish system). If you want to accomplish more, by actually discovering something new, plan on significant effort and expense and/or consider a co-operative project where you can pool resources and expertise with others.

It's not all bad news:

• Radio emissions from Jupiter, which can be very strong, overcome some problems with antenna size and equipment sensitivity. These emissions are concentrated in the HF band between 10 MHz and 40 MHz. There is a tendency for the pros these days to ignore planetary radio astronomy while pursuing increasingly obscure Big Bang theories with the sort of equipment only governments can afford. That leaves some way open for the dedicated amateur to pick up the slack in a neglected area of the field.
  
• Solar emissions, also very strong, are readily detected at most frequencies, supporting a good choice of lower cost, technologically straightforward investigative approaches. There's a lot going on on the Sun, and it's accessible. Check-out the Space Weather link you'll find elsewhere at this site.

The foregoing are probably your best bets for small-scale radio astronomy involving subject material at inter-planetary distances but at reasonable cost and with some prospect of doing real science.

If any this is discouraging, consider that serious exploration of the Universe utilizing modest resources for observing electro-magnetic phenomena (which include radio emissions) is possible provided we confine ourselves to the "near Earth" environment. Here we will find many interesting things happening, some at high energy levels, and where good spatial resolution - if required at all - is not always dependent on cumbersome apparatus. In some cases, investigation overlaps the science of geophysics where typical electro-magnetic effects are no longer termed "radio".

Other Readily Accessible Opportunities for Independent Researchers:

• Solar related phenomena: The sun's emissions induce disturbances in the Earth's magnetic field, variations in levels of UV/IR radiation, produce the aurora borealis/australis and generate ionospheric currents. Check the "Space Weather" link (later on this page) for what this is all about. Many of these interesting phenomena - and more - are detectable with a bit of ingenuity and effort.
  
  
• Seismic activity: Measurement of stresses in the Earth by monitoring electric fields, measurements of variations in gravity and related effects are possible with reasonably simple, carefully built equipment. We are really into geophysics here but there is a natural continuum between geophysics and astronomy. Where to draw the line, if that's important, is to some extent a matter of opinion.
  
  
• Weather phenomena: Lightning activity, storm tracking, Low Frequency radio emissions (below 100 kHz: "whistlers", etc.) monitoring are fascinating fields of study and many unanswered questions remain.  Storms produce copious radio energy with interesting characteristics.  Pressure systems generate transient tides in the Earth's crust and variations in the local electric field gradient. Meteorology isn't astronomy, yet, storms on Jupiter produce radio emissions avidly examined by radio astronomers here on Earth. It's all a matter of perspective.
  
  
• Centimeter wavelength radiometry(?): This almost belongs back in the "difficult" area of RA but the author of this site has experimented and discovered that inexpensive (<$100) LNBA down-converters used for satellite television reception  at about 10 GHz have some excellent properties. For example, with only the standard 18 inch dish, radiation from the human body (assuming it is still alive) can easily be detected at 30 ft. or so. It should be possible to do some serious radiometry with these and larger parabolas or horns. If it were arranged to synchronize the down-conversion oscillators in these units, several could be combined to form an exceptionally high resolution interferometer at low cost. We have not found any reports of such experiments.
  
  
• Meteors - what this subweb is all about: The Meteor Science General Index has links leading to full discussion and observations.  Observing meteors by radio offers many intriguing technical challenges and a chance to do real science. The relatively high signal strengths typical of meteor scatter simplify antenna and receiver design, compared to some other areas of radio astronomy. It is possible to obtain useful results with simple equipment and proceed to complex designs as you become more familiar with what is needed for advanced work.

Some Radio Astronomy Starter Links and Bibliography:

These links will help acquaint you with what is being done on a small scale by both amateurs and professionals  in Radio Astronomy. The SRT site is a superb resource, professionally prepared while SARA offers a wide choice of amateur contributions and opportunity to communicate with others sharing your interests:

	Society of Amateur Radio Astronomers
	Small Radio Telescope (MIT - Haystack Radio Observatory)

SARA supports most areas of accessible radio astronomy as well, including meteor research. Their web site includes numerous links of enormous value to the amateur plus complete articles by dedicated researchers. You'll also find an excellent bibliography and equipment sources.

There isn't a great deal of radio astronomy literature in the bookstores but the three "bibles" to many of us are Radio Astronomy, Electromagnetics and Antennas by Dr. John Kraus, one of the foremost radio astronomers of his time (Dr. Kraus died in 2004). Anyone seriously interested in any branch of Radio Astronomy should have  Radio Astronomy, at least. 

You'll have to brush up on your university mathematics to get through any of these but Radio Astronomy comes as close as anything to being approachable, especially in the opening chapters. Kraus writes lucidly, with the student always in mind. SARA offers other publications of interest plus its own Journal, prepared by talented amateurs with contributions by the pros from time-to-time.

Cygnus-Quasar Books ... Dr. John Kraus

For information on the more accessible areas of investigation in the electromagnetic spectrum including, but not restricted to radio:

	Jupiter Space Station - student projects
	Near Earth electromagnetic and charged particle activity
	Scientific American - various articles
	How to get the "The Amateur Scientist" on CD - this seems to have disappeared:-(

Meteor research links aren't included here because you will find them elsewhere at this site.

Unfortunately and inexplicably, Scientific American has discontinued "The Amateur Scientist" series but you can obtain all the proceedings on Compact Disk at a reasonable cost through the link above (well - maybe not - I am trying to find it again). This is a "must have" for anyone interested in independent/small-scale research in any area of science. The CDs describe numerous experiments and construction projects for apparatus to investigate everything from thunderstorm activity to electric currents in the ionosphere.

Finally, a short list of important literature on general electronic theory and practice for anyone undertaking a radio astronomy project in any sub-area of interest:

The ARRL Handbook, The American Radio Relay League, Newington CT

The ARRL Antenna Book, The American Radio Relay League, Newington CT

The Art of Electronics, Horowitz and Hill, Cambridge Press

The foregoing are all readily available at most technical bookstores.

In addition, Radio Meteor observers will want to seek out at the library (because it is out of print) this classic ...

Meteor Science and Engineering, D. W. R. McKinley, McGraw-Hill(1964)

Making a full copy of this should cost around $25 but check with the lender first concerning copyright restrictions. I had no problem at the University of Calgary.

The technology described in McKinley's volume is long out-of-date but there is probably no better collection anywhere of RADAR findings combined with a comprehensive technical/mathematical treatment of meteor dynamics. McKinley worked for the Canadian National Research Council. His objective was the development of systems for providing high bandwidth communications over long distances utilizing meteor plasmas as the means for sending these signals over the horizon.

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