Plan radio coverage (RF / ITM)

Where a line-of-sight viewshed shows what’s visible, RF mode estimates signal strength over the terrain — for repeaters, point-to-point links, WISP planning and antenna siting. Here’s the workflow.

1. Switch to RF

Click RF Propagation at the top of the control panel. The point becomes a Transmitter and the heights relabel to TX height / RX height. RF (ITM) is computed by the WASM engine — on the GPU when available, with a CPU fallback otherwise — so it works without a dedicated GPU, just more slowly. (The button is only unavailable if that engine can’t load in your browser, which leaves you the LOS viewshed.)

The LOS / Viewshed and RF Propagation mode buttons — Click RF Propagation to switch from a viewshed to a signal-strength estimate.

2. Set the RF parameters

An RF Parameters section appears:

Model — ITM / Longley-Rice, the irregular-terrain model used for real-world coverage. (Free Space Path Loss is listed as coming soon.)
Freq (MHz) — your operating frequency (e.g. 145, 433, 868).
Power (W) — the transmitter’s radiated power.
Min signal (dBm) — the weakest signal to map; anything below this isn’t drawn.

3. Heights, range & run

Set TX height (your antenna) and RX height (the receiving antenna), usually AGL. Choose a range and resolution and press Run Simulation. The overlay is now coloured by signal strength (low → high); recolour or export it from the Appearance section.

The RF Parameters section: Model, Freq, Power and Min signal — ITM / Longley-Rice with frequency, power and a minimum signal threshold.

Good to know. ITM accounts for terrain diffraction but not buildings (unless you include them), foliage or reflections — so coverage can be optimistic in built-up or wooded areas. ITM over a large area is heavy on CPU; see Performance. Treat the map as a planning estimate, not a guarantee.

Open the simulator →