Predictions come from the ITU's own reference implementation and are verified
numerically identical to a native build of it. Distances, bearings, MUF and the
diurnal behaviour all check out against reality.
The engine's reliability output is a known open defect — it reads zero
for every circuit tested and ignores the required-SNR input — so nothing here
displays it. What you see is SNR margin, which is verified responsive.
The A-score described in the design docs does not exist yet. It is meant to be
a calibrated probability, and calibrating it depends on resolving that defect first.
Reach maps are computed for whatever transmitter you pick, at 100 W into an isotropic
antenna. Power is applied on top as an exact offset. Wire antennas now carry their
real elevation pattern, applied per map cell — the distance to a cell sets the
take-off angle that path needs, and the pattern gives the gain there. Beams still use
peak gain applied flat, and still read optimistic on paths whose take-off angle they do
not favour, because their gain does not follow from the thin-wire model. Coarse passes
paint each sample across the block it stands for, so an early frame is a sketch until
the finer passes land.
The Learn page’s bounce simulator and band clock use a deliberately simple
teaching model of the ionosphere, not P.533. They show how propagation behaves, not
what your circuit will do, and they say so where they draw.
The antenna visualiser is a thin-wire model over perfect ground, not NEC. It
is pinned against the textbook constants it can be checked against — 2.15 dBi for a
free-space dipole, 5.15 for a quarter wave over ground — and it reports directivity,
so every gain figure on it is a lossless upper bound.
Solar activity is live: effective sunspot number from KC2G, refreshed hourly
by our own service so your browser never contacts theirs. Every page states which
source it used and how old it is, and falls back — to the snapshot published with
the build, then to a clearly-labelled placeholder — rather than quietly reverting
to a default sun.
Only the sunspot number is live in the sense that matters — it is the one
input P.533 actually takes. Kp, solar flux and NOAA's alerts are fetched and delivered
to your browser, but nothing reads them yet: they are neither displayed nor applied to
a prediction. Making a geomagnetic storm change the map means a penalty layer on top of
the engine, scaled by geomagnetic latitude, which is the A-score's job and does not
exist. Treat every prediction here as assuming quiet geomagnetic conditions.