Hi Greg
wrote in message ups.com...
I see what your saying and I agree, most probes would use a form of
tight beam communications, but there is alot of assumptions that can be
made based on what we know. Any interstellar probe to a high energy
stellar object would have an extreme amount of power at it's core used
mostly for traveling vast distances but also for 'signal to noise'
ratio for a star system who's background noise could easily distort and
overcome less powerfull signals. It might be possible to look for gamma
radiation with particular energy spike a distance from such a stellar
objects.

Please note that gamma radiation for communication (beacons or otherwize)
is very expensive : gamma 'photons' require extreme amounts of energy (h*f very high).
Consequently, the cost/bit would be very high.
Narrow beam optical communication would make a lot more sense.

Also, if one civilisation wanted to contact another, it might be easier
to send a signal from a place that most any civilisation would
naturally be curious about and easily detected, such as pulsars and
black holes. An added bonus would be that the transmitting civilisation
wouldn't need to worry about giving away their home system.


Nice idea. Place a beacon near a black hole or pulsar, since everyone in the galaxy would observe it.
However, black holes and pulsars are rather noisy across the spectrum.
So that would require even more power requirements for the beacon.
Also, its hard to aim accurately around a black-hole or pulsar, since gravity
will distord every beam. So the beacon would not have omnidirectional transmission capability.
Some part of the galaxy will literally be in a 'blind spot'.

Also, I don't even want to think about the logistics of getting an instrument of that complexity
and power transformers/generators placed around a black hole, but hee, ET can do anything with enough technology.
Would be very costly though. For any civilisation...

Maybe a beacon on the home planet or a nearby moon would be most cost-effective.