Below are two examples of graphs that have broadband interference. Note that the signal covers many frequencies simultaneously (hence "broadband"). While we would not reject this kind of signal out-of-hand as these can be generated by pulsating signals. In the first example below, the signal lasts for the complete 107 seconds and is therefore earthly in origin. In the second example, something like a strong local radar was turned on during the session and completely saturated the SETI@home detectors. Also note in the first example that the signal is so strong that it "drives" all the other signals way down (since the SETI@home screensaver normalizes the graph).
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SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.