[fredsmith42]

Would this be applicable to SETI?

[gus_massa]

No. Any signal that reach here from other star system will be too faint, and you need a huge antena to recollect enough power to detect the signal over the noise. The discovery is very overhyped in the press article (as usual).

Also, the detector is small, but it need to be cooled to very low temperatures, so the whole system will be not as small as the article describe.

[mrfusion]

A simple dish or antenna can collect the signal. Size it to your purpose. A sensor is just the last step of what you do with that signal.

Think of putting your smart phone camera up to a telescope eyepiece.

[varjag]

Antenna geometry restricts the effective frequency range.

[calibas]

Where did "cooled to very low temperatures" come from? The Army article said it was done at room temperature: https://www.army.mil/article/212935

[greglindahl]

For radio astronomy purposes, the signal is so weak that thermal noise in the detector is always an issue.