Reflection geometry

Map: the ground footprint (green) and the L1 first Fresnel zones (amber). Fit to sensor area (top right) frames the station and its footprint.
Azimuth sectors: drag across the compass toward the water to draw a sector (up to eight; × removes one). Only satellites inside the sectors are used.
Elevation window: about 5°–45° with the low-cost antenna of the reflexa micro unit, which keeps the reflection visible higher than a geodetic antenna. Lower the top if the near shore or the wall below the unit shows up in the footprint.
Antenna height above the water: an optional estimate, 0.05–250 m; measured or estimated by eye, within a factor of two is enough. Leave it empty (clear it with ×) when you have no idea.
Water-distance (RH) search range: keep Auto. The unit searches the widest range the elevation window resolves (or half to twice your estimate) and widens it when reflections land on its edge.
Measured height: once the unit has three accepted arcs or more, the page shows measured RH x ± σ (n arcs) next to your estimate and draws the map with it; Use the measured height writes it after you confirm.

If you set the range yourself, Let the unit adjust the water-distance range automatically decides what happens when the water turns out to be outside it:

Ticked (default for a new configuration): at the start of the next session the unit moves the range onto the height it found. Your own range stays saved and the page shows the range in use next to it.
Unticked: the unit never changes your range; it only warns, and so does the page.

With Auto the box is always ticked. Background: where the reflection happens and site requirements.