Earth's "radio bubble" is well over 100 light years across now. If there are aliens out there, they are probably already on their way to ask us in person why Ross, the largest Friend, doesn't simply eat the others.
We have literally no idea what technology the alien could have.
Show a spacecraft to someone from the middle ages and they would think it's magic.
There is physics that has not been discovered. Lots of things are still unexplained.
> no, the aliens are not able to collect radio waves from below the noise floor
Before we had quadrature modulation and quadrature phase shift keying, we thought we had hit the noise floor for wireless bandwidth. After we thought we really hit the ceiling, we had beamforming. There's stuff that hasn't been thought of. We don't know the unknown unknowns.
Analogue TV has always felt so much more clever than digital TV to me, at least from a purely technical standpoint. I guess that's because we're mostly digital natives now, so video codecs seem ordinary and programmable electron rayguns do not.
We are already using spectroscopy to gain insights into the chemical composition of exo-planets, and we have barely begun doing this kind of research. In even just a few decades we'll be massively better at this.