[ghporter]

Since the 1980s (at least), human electronic communication has moved more and more to very focused, inwardly directed signals. Satellite communications and especially "broadcast TV" have moved more and more to tightly aimed communications systems that allow small antennas to pick up everything without transmitters splattering signals all over the place using tons of RF power. This is made possible through the use of a number of techniques that are intended to increase the available bandwidth; spread spectrum approaches, based on the same principles that WiFi uses; the distant transmitter can put out quite low levels of power because the receiver "knows" where to look for the actual signal in the background noise.

It seems to me that, except for actual terrestrial signals for local radio stations, everything is moving toward digital signals that are crafted to use less power and be very directional. Broadcast HDTV is an example; it's digital, mostly UHF (line of sight), it's transmission pattern appears to be carefully designed to direct the signal toward the coverage area without blasting signals upward, and while that leads to better coverage, we're not telling ET that we're still here.

So my thought is, "what if the whole concept of SETI is based on 1950s-era blasting out signals into space?" If we think of our own move toward directional communications as an indicator, doesn't it sound like we're only looking for a very short-lived burst of ET's "I Love Lucy", with a real possibility that we'd miss that entirely most of the time?

[subego]

Maybe that's what's keeping the aliens away.

If they swing by and can still hear Hannity on the AM, you're judged not yet worthy to join the Galactic Federation.

[Thorzdad]

Originally Posted by subego 

Maybe that's what's keeping the aliens away.

If they swing by and can still hear Hannity on the AM, you're judged not yet worthy to join the Galactic Federation.

I would think hearing Hannity would put us in the "Exterminate before they can get off their planet" category.

[starman]

If aliens started the same way we did, we'd pick up on their 1950s-type signals, right?

[subego]

If we're looking in the right place with a sensitive enough telescope.

And now, as has been posited, over the right tiny stretch of time, which makes the haystack bigger.

The original idea was we'd be spitting this stuff out for several thousand years.

[reader50]

Over-the-air broadcasts aren't vanishing. Even if you use directional antennas, they'll still radiate out of the atmosphere in those directions. Last I heard, the Earth radiates more radio wattage per square meter (average) than the Sun. Of course, the Sun has a lot more square meters ...