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| \sec Radio astronomy receiver |
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| In the beginnings of radioastronomy, the receivers were constructed as simple stations with single antenna or multi antenna array with fixed phasing. This approach was used because of the existing limits of electronic components and technologies. The main challenges of those times were the problem of noise number and low sensitivity, both present due to the poor characteristics of active electronic components such as transistors and vacuum tubes. |
| At the beginnings of radioastronomy, the receivers were constructed as simple stations with a single antenna or a multiple antenna array with fixed phasing. This approach was used because of the existing limits of electronic components and technologies. The main challenges of those times were problems of noise number and low sensitivity, both present due to the poor characteristics of active electronic components such as transistors and vacuum tubes. |
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| Most of the present-day operating radioastronomy equipment has been constructed in similar manner. It was produced usually shortly after the WWII \glos{WWII}{Second World War} or during The Cold War as a part of military technology. |
| Most of the present-day operating radioastronomy equipment has been constructed in a similar manner. It was produced usually shortly after the WWII \glos{WWII}{Second World War} or during the Cold War as a part of the military technology. |
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| Today we have an access to components having quality, repeatability and price completely different from the components accessible by previous generation of radioastronomers. That is why we can develop better radioastronomical equipment, powerful enough to make new astronomical discoveries possible.\fnote{Most of astronomy-related discoveries in the last fifty years came from radioastronomy.} |
| We have an access today to components with much higher quality, repeatability and a lower price as compared to the components accessible to previous generation of radioastronomers. That is why we can develop a better radioastronomical equipment, powerful enough to make new astronomical discoveries possible.\fnote{Most of astronomy-related discoveries in the last fifty years came from radioastronomy.} |
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| We have the capacities necessary to develop a receiver which will have wide bandwidth, high Third-order intercept point and preferably an option for phase and frequency locking to other receivers located at another radioastronomical site at Earth. Currently there exist several receivers with the above-mentioned parameters, for example USRP2, USRP B210 \glos{USRP}{Universal Software Radio Peripheral} or HackRF and all are commercially available. However all of them lack scalability and have high prices. It is exactly the scalability and redundancy that are the main requirements of noise reduction algorithms. |
| We have the capacities necessary to develop a receiver which will have a wide bandwidth, a high third-order intercept point and preferably an option for phase and frequency locking to other receivers located at another radioastronomical site at the Earth. Currently there exist several receivers with the above-mentioned parameters, for example USRP2, USRP B210 \glos{USRP}{Universal Software Radio Peripheral} or HackRF, which are commercially available. However all of them lack scalability and have higher prices unaffordable to our amateur radioastronomy network. Scalability and redundancy that are the main requirements of noise reduction algorithms which motivated this diploma project. |
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| New radio astronomy systems such LOFAR \glos{LOFAR}{Low-Frequency Array} are explicit examples of the scalability and redundancy approach. LOFAR has completely different and novel structure developed to solve the problems of radioastronomy signal reception. It exclusively uses multi antenna arrays and mathematical algorithms for signal handling. Radio signals recorded by LOFAR can be used in multiple ways: radio images can be computed (if sufficient cover of u/v plane is achieved), radiation intensity can be measured, spectrum can be analysed for velocity measurement, etc. |
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