The only sign of a detection was a toast. It is gone in seconds, and an operator
who was tuning at that moment had no way back to it — for an event that lasts
hours and happens a handful of times a season, that is the wrong shape entirely.
The badge sits at the right-hand end of the status bar, before the clock: an
opening is a state of the WORLD, not of this station, so it belongs with the
time and the logbook rather than among the rig and amplifier chips.
Knowing when to go out was the real work. Nothing announces that an opening
ended, and the detector deliberately says nothing more about a band for 45
minutes after announcing it — right for a message, useless for a badge. So it is
inferred: every qualifying spot on that band pushes a deadline out, and when
they stop arriving the badge fades by itself. Fifteen minutes, comfortably more
than the detector's own twelve-minute window, so a quiet couple of minutes
mid-opening does not blink it off and on again.
Gated on the same distance floor the detector uses. Without that, a band busy
with short-range tropo would hold an Es badge lit indefinitely on spots the
detector itself had refused.
The detection shipped reading whatever the operator's cluster nodes happened to
carry. On VHF that is a few hundred skimmers, nearly all of them on HF: a 6 m
opening carrying 869 stations reached OpsLog as a handful of spots or none, and
Nexus flagged it on the same PC while OpsLog stayed silent.
internal/pskr subscribes to pskr/filter/v2/<band>/# on PSK Reporter's MQTT
broker. Every ordinary station running WSJT-X reports what it decodes, so the
difference is two orders of magnitude rather than a threshold. The feed's shape
suits us exactly: BOTH grids are in each message, so distance and bearing are
arithmetic — no lookup, and no DXCC-centre approximation, which is what made the
cluster path's bearings coarse. The geometry is injected from app.go so it stays
the same arithmetic the cluster path uses; two answers to one question is how a
bearing quietly becomes wrong.
Volume was the design constraint, not the protocol. Six metres open is thousands
of messages a minute and this runs on some very old PCs, so nothing is kept or
persisted in the watcher: each message is parsed, measured and handed on or
dropped, and the detector's existing window does the deciding.
And the part that was the real bug: enabling the watch now ARRANGES ITS OWN
SOURCES. It adds the two RBN nodes when missing and brings the feed up. A
feature that silently depends on sources nobody can know are needed does not
look unconfigured, it looks broken. Matched on host and port, not name, so an
operator who renamed theirs does not get a duplicate — which the detector would
read as twice as many stations, and announce an opening that is not there.
Turning it off leaves the nodes alone: they may have been wanted for their own
sake, and removing a node someone is using is worse than leaving one they are not.
Observation, not prediction, and it needs no new data source: the cluster event
worker already enriches every spot with the great-circle distance and bearing
from the operator's grid, which is exactly what a single-hop Es detection rests
on.
The signature is four or more DISTINCT stations at 500-2400 km inside a 90
degree bearing sector within twelve minutes. Each constraint earns its place:
distinct callsigns because one station spotted by six skimmers is six spots and
one station; the lower bound because a 6 m contact under 500 km is ordinary
tropo and says nothing about the ionosphere; the upper bound because past one
hop the bearing test stops meaning anything; and the sector because a real Es
cloud illuminates a direction, which is what separates an opening from a merely
busy evening.
Fed AFTER the Historical guard in the worker. A SH/DX reply replays a hundred
past spots in a second - precisely the shape of a burst - and would announce an
opening that ended hours ago.
Season LABELS, it never gates. Both hemispheres get a summer peak and a lesser
winter one, and an opening outside those is announced with "unusual for the
season" attached: the rare one is the one an operator must not hear about last.
One announcement per band per opening (45 minute quiet period). An opening runs
for hours and produces hundreds of spots; one alert is information, forty is
noise.
rouggy