Sites progress from unknown to rumored to mapped. Rumors make players search; Direction-Finding stations make enemy activity detectable without revealing free exact positions.

Rumors can lapse, only a limited number can be open, and Cartography Institute adds one server-wide rumor slot. Tier 2 and Tier 3 sites need a regional Survey Station at level 1 and 2 respectively. Demolishing it removes the tier access it provided.

Mapped airfields can build Loop, Adcock and Watson-Watt stations. Their network reaches 40 km, 55 km and 70 km. Settlements and airfields relay from level 1, Factories from level 2 and Sources from level 3. A relay listens about 22 km from itself; the station airfield listens about 30 km.

A bare airfield still anchors a 75-degree rumor direction. Station level narrows that sector and expands threat-network reach, but every threat contact remains bearing-only.

Terrain widens a station's sector without shifting its centre. Fly 8-12 km from the station at 300-900 m above ground and remain in one 30-degree sector for 20 seconds to calibrate it. Twelve completed sectors persist across sorties, apply to the whole station network and reset when the station is upgraded. Calibration is fully effective for 180 in-game days, fades by day 365, and cannot remove night error.

Raw threat cones have no range. With a Direction-Finding Control Centre, two reports can produce a bounded plotted fix or a true point when the area is sufficiently small; the Control Centre requires three Adcock stations. Map a Rumor with SRS gives the player procedure.