Even at C-band, a local interferer causes high spikes on the solar plot. I was so far only successful in recording solar and lunar noise with C-band and Ku-band satellite LNBs, and a 60x80 cm offset antenna at C-band a 1-ft dish was OK. I could hear the solar noise but all records were only full of spikes without any reasonable solar noise visible. I was trying to detect and record solar noise over the UHF range as well as around 50 MHz with various antennas and receivers but the local TV and other interference caused that all attempts to record anything were bad.
