AMATEUR  RADIO  ASTRONOMY
              Western  Australia
                 Hans  Michlmayr  
                         (vk6zt)                                                                               
Radio Astronomy
This website reflects the results , or sometimes a lack of it, of persuing Radio Astronomy
as a hobby , or as some have pointed out to me , as an obsession.
The intention is not to give here an in-depth radio astronomy course, there are countless publications around to cover this amply. Instead here the emphasis is on practical , can-do
projects , with the focus on home constructed equipment , trying to maximise the cost vs.
performance ratio of  "amateur radio telescope making"  .

It is however appropriate here to explain the differences between typically available radio telescope configurations to amateurs and the rationale for specifically opting for the phase switching technique instead of other interferometer systems.  ( see  PHASE SWITCHING)

As with many sciences , radio astronomy encompasses a large field of specialized sub categories, so enthusiasts often have to decide into which particular area they should pour their efforts . In practical terms the limits will be one's own subject knowledge, educational background , time and finances.  If we already have experience in electronic design and construction , the financial strain can be better controlled.  In any case , unlike the optical astronomy amateurs , their radio astronomy counterparts do not have such a huge variety of commercially produced equipment at their disposal . And the few items which are being sold are either quite expensive , because the equipment is not mass-produced, or are a bit too primitive for more serious usage. Consequently radio astronomy amateurs frequently opt for acquiring certain key elements of home consumer electronics and cobble this together with home made electronics and/or software in order to circumvent the need to construct purpose built electronics for the job. This approach can be made to work with reasonable success,
but will usually entail inherent performance restrictions , because the equipment was originally designed for something totally different.  Such systems are often combined with very good software ,which cannot necessarily compensate for the hardware shortcomings.  Yet for computer enthusiasts who simply like to find something deep and meaningful to do for their otherwise under-utilized PCs, such a set-up would probably suffice .  I'm of course guilty of being somewhat obsessed with hardware, similar to an (optical) amateur astronomer who spends most of his time building telescopes, but not doing much observing.....
There are however a number of observations for which a software approach is not only better but mandatory , like charting, spectral , pulsar and SETI work . The increasing availability of SDR type of equipment reduces much of the RF electronics burden, but still at a substantial cost factor , especially if the items have to be imported from another country . Available soft -
ware often will dictate what commercially produced equipment has to be purchased , which in turn can ultimately put limits on equipment configuration and applications.

Before I first began this rather unusual and lonesome hobby (in 1973) , it was inconceivable to me  to actually build a radio telescope in my own backyard and get anything tangible from it. At that time I was an avid electronic constructor / radio amateur and also a keen (optical) amateur astronomer ,so it was not without logic to combine these two activities .

The inspiration came from reading Frank Hyde's book "Radio Astronomy for Amateurs" and later on from John R. Smith's radio astronomy publications in the BAA journals .
In the 1970's there was no such thing as modern ultra-low noise RF amplifiers and amateur radio astronomy equipment was quite "deaf" by today's standards. Therefore we had to find ways to extract the cosmic signals from very much greater receiver noise than today.
   John Smith provided a very convincing argument for the construction of 2-antenna phase switched interferometers as the preferred modus operandi for amateur equipment. I found the logic for this was very persuasive and feel it holds true right to the present day.   For this reason most of my radio astronomy projects are based on this technique .  It is electronically simple, efficient and direct, meaning you get immediate results without involving a PC for anything else but charting. This technique also largely cancels base line drift (temperature
problems), allowing operation without front-end temperature control .
Without phase switching and the availability of ultra-low noise signal amplifiers amateur radio astronomy would have largely been restricted to recording solar and galactic noise and the occasional HF radio noise from Jupiter . With phase switching amateurs can now routinely observe fainter radio sources of perhaps less than 10Jy with relatively small antennas .

Over the years a number of other interesting radio astronomy activities were explored, and most are featured on this website. I'm guilty of failing to keep this website up to date with the various projects , technical details and observational results over the last few years.
This is being addressed at the moment and should be completed within a year .
Therefore not all page links are functional as yet . If you require info on any subject for which the designated link button is inoperative, please email me direct .
 
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