long range signal repeaters

[...] explorers encountered curious structures(?) in the region [...] towers of wood that are covered in vines in specific patterns, with large leaves poking at the top pointing to what seems like a straight like, seemingly by design of someone [...]
~ exploration report letter, march 1722

by the means of controlling the growth and position of naturally occurring qoi-nen vines, these dragons did create some of the very first radio signal repeaters, which take signals from one direction and echoing them forward in a straight line

these structures are resilient to climate conditions (except for radio fog) and really pretty when not blending with the environment, constructed at the edges of forests or in arrays extending tens of kilometres, these did let the various tribes expand their communication further than before, largest recorded array letting communication travel along 18 kilometres

although fancy, repeated communication is not real time, with each 'node' taking some time between receiving a signal and echoing it forward (it did use a biological rudimentary processing for noise reduction), and only being able to transmit one thing at a time in each direction

it is yet unknown the specific time these were first created, but from historic records of certain tribes, the instructions of how to construct those has existed since at least 1000 CE