Tywyn
Wales · MW
Position 52.582920, -4.096237 Grid reference SH58070041 Nation Wales Ground height 6 m Antenna height — OpenStreetMap has a mast 41 m away, matched on proximity alone [I] . That is an independent check on the position, not a correction to it — see how positions were checked .
On the map
Tywyn is not the strongest signal anywhere the model predicts — it is shown here in place. That is normal for a relay, which fills in inside a main station's area.
Medium wave Medium wave is listed but never predicted. It propagates by ground wave by day and ionospheric skywave by night, and the model used everywhere else on this site — ITU-R P.1812 — starts at 30 MHz and does not describe either. A coverage figure here would be invented, so there isn't one.
Transmitter data is Ofcom's; every dataset and the terms it is used under are listed under sources . Coverage figures are modelled, not measured, and are systematically optimistic .