Free RF tools

Check the numbers behind the map.

Unit-aware calculators with visible formulas, assumptions, and shareable inputs.

Propagation

Free-space path loss

Calculate ITU‑R P.525 basic transmission loss from distance and frequency.

Open calculatorPower budget

RF link budget

Combine power, gain, loss, distance, and frequency into EIRP and received power.

Open calculatorUnit conversion

dBm ↔ milliwatts

Convert logarithmic dBm values to linear milliwatts and back.

Open calculatorReference data

Building-material attenuation

Published RF loss of drywall, brick, concrete, glass, and wood by band and thickness, with sources and limits.

Open reference

Free API

Every calculator is also a free API.

Call any tool from a script, a spreadsheet, or an AI agent. One OpenAPI document describes them all.

No API key. GET or POST. Every result carries its formula, assumptions, and source.

API docs OpenAPI spec llms.txt

Request

curl -G "https://siterfapp.com/api/v1/tools/link-budget" \
  -d transmit_power_dbm=20 \
  -d transmit_gain_dbi=4 \
  -d receive_gain_dbi=0 \
  -d cable_loss_db=1 \
  -d other_loss_db=0 \
  -d distance=10 \
  -d distance_unit=m \
  -d frequency=5.5 \
  -d frequency_unit=GHz

Response (abridged)

{
  "tool": "link-budget",
  "inputs": {
    "transmit_power_dbm": 20,
    "transmit_gain_dbi": 4,
    "receive_gain_dbi": 0,
    "cable_loss_db": 1,
    "other_loss_db": 0,
    "distance": 10,
    "distance_unit": "m",
    "frequency": 5.5,
    "frequency_unit": "GHz"
  },
  "result": {
    "eirp_dbm": 23,
    "path_loss_db": 67.25503701176825,
    "received_power_dbm": -44.25503701176825
  },
  "next_steps": [
    {
      "id": "rf_solve_coverage",
      "why": "Received power here assumes free space: walls and floors between the radios are not modelled. Whole-building coverage needs a floor plan.",
      "requires": "account_with_approval",
      "status": "available",
      "learn_more": "https://siterfapp.com/agents/#rf_solve_coverage"
    }
  ]
}