While writing this I though of algorithm that might work better to maximize amount of civilizations you reach. This would require a relatively stable space transmitter, or series of coordinated ground transmitters:
1. Pick a set of stars S that potentially can support advanced civilization and are located closely in a region of space (so you do not have to reposition telescope a lot).
2. Start sending signals primer signals to stars. For signal S[x], temporal difference between S[x] and S[x+1] would a set amount shorter than temporal distance between S[x-1] and S[x]. Primer signals are short and cheap, transmitting entire Wikipedia should take way longer (Weeks, months, maybe years?).
3. Once time between primer signals reaches some threshold start transmitting data set.
Idea is that this will give advanced civilization potentially listening a chance to prepare to receive full transmission, while avoiding costly repeats of big data set.
[I did the calculation this way because back in about 1990 I had the brilliant idea of a satellite that broadcast the sum total of human knowledge to everyone on Earth, and figured out that a single TV channel could basically handle it on a 24 hour cycle, based on what we knew then. Which just goes to show how stupid brilliant ideas can look a short time later...]
- simultaneously transmit on a lot of frequencies from LF through light
- modulate a minimal "intelligent" message in a wide variety of ways (frequency, amplitude, pulse, phase, polarization, etc.) and also unmodulated (simple carrier).
- assume widely different time scales, so the message should be sent so that it takes 1 second, one minute, one hour, and one day
- alternate sending/receiving on the same lock-step
The goal is to get another intelligent life form to realize we are intelligent and trying to communicate, but there appear to be tons of assumptions baked into the approach used in the article.