The "listening device" on Trisol was used to send transmissions to Earth. Later those transmissions were observed by another distant civilization.

Why did it even have the ability to transmit, let alone under the control of a single operator?

  • 1
    I've edited to make the language a little clearer
    – Valorum
    Commented Sep 11, 2021 at 10:32

1 Answer 1


The transmitter element of the station is very low powered. Its function isn't described in the books, but we know that the Trisolarians have a fleet of spaceships and satellites in orbit that would need to be communicated with.

“Listening Post 1379 is a small facility without high transmission power. The maximum range may be twelve million light-hours, about twelve hundred light-years.”

By comparison, a typical Earthican satellite broadcast station (of which there are tens of thousands) would easily be able to beam a signal that strong into space if we knew what direction to point it in with any degree of certainty.

  • The problem is that transmission eventually reached hostile civilization and so Trisol was destroyed. That (transmitter preсense of the station) should not have happened. And communication with the fleet requires much less power. Also it could be arranged via some kind of central (and better controlled) transmitter. Commented Sep 11, 2021 at 15:12
  • @YaroslavKornachevskyi - The Trisolaran in charge of that station had been working without fault for more than a thousand years. His risk profile was, apparently, quite low
    – Valorum
    Commented Sep 11, 2021 at 15:16
  • By the way, the type of transmitter was the same: "It was a record of the dead world’s three communications with another location using medium membrane". Commented Sep 11, 2021 at 15:35
  • @YaroslavKornachevskyi - Sort of. The first transmission (from Earth to Trisol) was sent using solar amplification. Presumably the subsequent ones were mundane radio signals.
    – Valorum
    Commented Sep 11, 2021 at 15:39
  • It could be, still all messages were called "medium membrane", or "primitive". And also there is "short membrane", which could be for the radio. Commented Sep 11, 2021 at 15:43

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