I have read through the science newsletters the last days and I'm curious about a specific question referring to this old newsletter about the Clickplot analysis. If I'm looking at the full Clickplot, even zoomed in fully, I can clearly see that the vertical yellow lines which are test signals or "birdies" consist entirely of yellow dots (=strong signal), while all the weaker red dots all look like randomly crowding the picture.

What I'm curious about is, if SETI@home tries too inject very weak test signals into the system, too. In my opinion signals as week as the weakest signals that are actually returned by the clients would be required. If you would inject weak test signals and then it would turn out that clients are returning signals as weak as the test signal, but not or only a small percentage of the actual test signals, I would interpret it that way, that clients are not capable of actually detecting that weak signals and are just producing random "signals" from the random background noise. In this case detection threshold would need to be adjusted upwards.

Since SETI@home staff are not stupid I assume that they already thought of that years ago. I'm just curious because I've nowhere read about such sensitivity tests of equipment/software on this website. BTW, where in the system are the signals injected anyways? I suppose SETI@home is not allowed to go with an actual radio transmitter onto the Arecibo antenna cause that might screw up other research. The next logical place would be to connect "injection cables" to the cables that are coming from the receiver in front of the recorder.

I'll be blogging about this soon, I hope. It turns out that we don't need to inject weak test signals because there are plenty of weak harmonics of strong (RFI) signals in the data.

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@SETIEric@qoto.org (Mastodon)

Thanks for the answer. Didn't think that RFI could actually be useful for something :). Making the best of something that's disturbing the project most of the time is pretty smart.