Location of Observatory - RFI and Ground Noise

One of the advantages a professional radio astronomer has is that, generally speaking, the observatory is located in area which is protected against radiofrequency interference (RFI). If the amateur observatory is not located in the wilderness, far from civilisation, the effects of neighbours' plasma screens and the myriad of other electronic devices which radiate radio frequency energy will have a significant negative effect on efforts to receive faint pulsar signals from light-years away. The characteristic of amateur observations which can counter this is that he/she is not usually limited in observation time. For the location of HawkRAO the best times for observing Vela are the months from January to July when it transits between the local hours of midnight and dawn. This reduces the amount of RFI due to the perpetrators being asleep...

Nonetheless, the minimum strength pulsar detected can be severely compromised by RFI. Not only due to intermittent carriers (which can easily identified and avoided), but more insidiously, the general noise floor level can be raised - which is not easily identified unless calibrated measurements are made. This can be designated Trfi.

In addition, ground noise from buildings, trees and other objects add to the system temperature through sidelobe and spillover responses of the antenna, further compromising the sensitivity. This can be designated Tsidelobe.

In practice, in usual amateur observatory environments, the sensitivity radiometry equation becomes...

...which can be the reason why there is a lack of success with small antennas.