Mark Solar Radiation is extremely wide band from VLF to Gama and beyond. Man made signals are extremely Narrow Band compared to the sun.Although that is true to some extent, if the man made radio signals weren't stronger, you wouldn't be able to hear them over the RFI from the sun. In fact, on some bands, 80m and 160m, the natural noise floor caused by nature is very high and takes more power to be heard over.
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