Astronomers measure signals in terms of Janskys (1 Jy = 1×10-26 Watts/m2/Hertz, and the GBT often measures signals of milli- or even micro-Janskys. That’s a decimal point with 32 zeros after it:
0.00000000000000000000000000000001 W/m2/Hz
This is much less than, say, the energy of a single snowflake landing on the ground. Another possible way to look at this is that if you were to take your cell phone to Mars, its energy as seen here on Earth would be much, much greater than the energies frequently measured by the GBT. This is why it is incredibly important for the science we do that we are protected by two separate regulations which protect the GBT and the other site instruments from locally produced radio frequency interference.
The Green Bank Interference Protection Group is responsible for minimizing radio frequency interference to astronomical observations from equipment and activities at the Observatory, in the West Virginia Radio Astronomy Zone (WVRAZ), and in the National Radio Quiet Zone (NRQZ). If you have any questions, feel free to reach out to the Green Bank IPG (ude.oarn@gpibg or ude.oarn@dael-gpibg).
Below is an example plot of RFI data taken from the CHIME Outrigger at the GBO site. Digital TV signals make up a great number of signals observed (RFI Memo 165). RFI data from CHIME, and other instruments on site, are used by the Green Bank Interference Protection Group to help identify and minimize radio frequency interference.
