re: #29 ericblair

Yes, sort of like triple locking the front door and leaving the garage open.

Frequency hopping is used quite a lot in military comms to prevent hostile jamming. It can also make a signal almost impossible to detect, as the signal can weaker than the natural background noise and still be received correctly.

3G cellular as well (but not 4G), and Bluetooth are based on frequency hopping. These can be jammed because everyone knows their hopping codes, but helps the radios deal with interference problems.

Oh, the technology is much better than it was 50 years ago. All cell phones use it, and you don’t have to raise your voice. In fact, I’m always having to tell people to speak more softly because their voice is distorted from the amplifier clipping.

As for being impossible to detect, you know the old saying: “Any sufficiently advanced communication is indistinguishable from noise.” People need to think about that when they talk about eavesdropping on alien signals. After having radio for barely a century, they couldn’t get anything out of our signals.