LPWAN Coverage Calculator

Free-space range has a closed-form algebraic solution because the Friis path-loss equation is a simple function of log-distance. But once environment attenuation (extra dB lost per kilometer) is added, the total loss equation — FSPL(d) plus environment-loss times d — mixes a logarithmic term with a linear term, which has no clean algebraic inverse. The calculator instead uses 50 iterations of bisection search to numerically converge on the distance where the two sides balance, which is precise enough for practical link-budget planning.

The calculator applies +6 dB of extra link margin for every doubling of gateway height above a 2-meter reference height, using log base 2 of (height / 2). Going from a 15-meter rooftop mount to a 60-meter tower — a 4x height increase — adds about 12 dB of margin, which the calculator then re-solves through the same bisection process to get a larger effective range.

Fade margin is a safety buffer for interference and multipath fading, and it's subtracted from the raw link budget to get the 'available path loss' the signal can spend on distance and environment attenuation combined. Subtracting it upfront means every downstream range calculation — free-space, effective, and height-adjusted — already has that safety margin baked in, rather than being an optimistic best-case number you'd have to discount yourself.

The coverage area output is simply π times the height-adjusted range squared, which assumes uniform, obstruction-free propagation in every direction. Real-world coverage is rarely circular because terrain, foliage, and building density vary by direction from the gateway, so treat the reported range and area as a best-case planning estimate rather than a guarantee at every compass point.