ConceptsNarrowband signal
Concept · radio astronomy · in 3 mysteries
Narrowband signal
A radio signal confined to a very small range of frequencies, which nature rarely makes.
Natural radio sources spread their power over wide bands; transmitters concentrate it in a few hertz. A signal much narrower than any known natural emission is therefore the classic sign of technology, and the reason the Wow! signal was flagged in 1977. Interference from Earth is narrowband too, which is why a signal must be seen again, from another telescope, before it counts.
Where it comes up
Wow! signal
The 2025 reanalysis used previously unpublished archive data and found that cold hydrogen clouds produce similar narrowband signals.
1I/'Oumuamua
The Green Bank Telescope observed on 13 December 2017 across 1.1-11.6 GHz and found no narrowband signal, a limit of 0.08 W for an omnidirectional transmitter on the object .
Cite it
Mysteries Department. (2026). Narrowband signal [Concept CPT0DECW03SJNS9]. https://mysteriesdept.com/r/CPT0DECW03SJNS9
@misc{mysteriesdept_cpt0decw03sjns9,
title = {Narrowband signal},
author = {{Mysteries Department}},
year = {2026},
note = {Concept, catalog key CPT0DECW03SJNS9},
url = {https://mysteriesdept.com/r/CPT0DECW03SJNS9}
}