Also known as: meteor scatter, meteor burst, MS
Meteor scatter (meteor-burst communication) is a VHF propagation mode that reflects radio waves off the short-lived columns of ionised gas that meteors leave as they burn up in the upper atmosphere.1 Each trail supports a usable path for only a fraction of a second to a few seconds, so meteor scatter delivers long-distance contact in brief “pings” and “bursts” rather than a steady signal.
How it works
Billions of tiny meteoroids strike the atmosphere every day, most no larger than a grain of sand. As one ablates around 85–110 km up, it ionises a long, thin column of air. That column of free electrons can reflect or scatter VHF signals for as long as it persists before winds and recombination disperse it. Trails fall into two classes:
- Underdense trails — the common, faint ones. They act like a cloud of independent scatterers; the reflection rises and decays exponentially within a few tenths of a second (a “ping”).
- Overdense trails — from larger meteoroids. They are dense enough to reflect like a metallic column and can sustain a usable path for several seconds, sometimes with strong signal and audible Doppler as the trail drifts.
Because any one trail is fleeting, meteor-scatter systems transmit in short, repeated, high-rate bursts and wait for a trail to bridge the path. The reflecting region sits at E-layer height, giving typical single-hop ranges of roughly 1,000–2,000 km. Activity follows the meteor flux: a baseline of sporadic meteors runs all the time, peaking before local dawn, and rises sharply during annual meteor showers.
In practice
Historically, “meteor-burst” data networks (such as remote environmental telemetry) exploited the mode for low-rate, store-and-forward messaging over long distances without satellites. Today it is best known in amateur radio through digital modes purpose-built for it — FT8’s fast cousin MSK144 packs a complete message into a short, repeated frame so a single ping can carry a whole exchange. Its ion supply overlaps with sporadic E, and the two often coexist on the low VHF bands.
Relevance to SDR
Meteor scatter lives squarely in VHF, so it is accessible to ordinary SDR hardware — an RTL-SDR or Airspy can capture the pings, and the decoding is done in software. For a trunking scanner like GopherTrunk the mode is neither a target nor a normal interference source; it is an illustration of how even transient, exotic reflectors briefly extend VHF reach far past the radio horizon that otherwise bounds a scanner’s coverage. GopherTrunk models none of this and simply decodes whatever the front end receives.
Sources
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Meteor burst communications — Wikipedia, on ionised meteor trails, underdense vs overdense reflection, burst timing, and VHF ranges. ↩