Actually, people do there all the time. There are lots of tables and graphs of sun's noise temperature, tellin the engineers how much noise you should expect coming from the sun in every frequency, season, place on Earth (or outside it - really, sattelites often get this noise), azimuth, zenith, or whatever.
The fine print: nobody wants an antenna to to look straight to the Sun. The noise from it becomes a real problem, specially in higher frequencies.
E.g, satellite TV, at least here in Brazil, stops working for a up to an hour a day for some weeks because of it. This happens twice a year, and its cause is the Sun getting behind the satellite (or the other way round, as Copernico told us).