This tool uses the SPLAT! implementation of the ITM / Longley-Rice model to calculate radio coverage. Below is a list of the adjustable parameters with their meanings, units, and recommended values.
| Parameter | Description | Units | Default Value | Notes |
|---|---|---|---|---|
| Site Name | Name of the transmitter site | Text | None | Optional, label for the transmitter site. |
| Latitude | Latitude of the transmitter | Decimal Degrees | None | Transmitter location. |
| Longitude | Longitude of the transmitter | Decimal Degrees | None | Transmitter location. |
| Antenna Height | Height of the transmitter above ground | Meters | 2 m | Should include mast or tower height. |
| Transmit Power | Power output of the transmitter | Watts | 0.1 W | Set based on your Meshtastic device and region, defaults to 0.1W / 30 dBm. |
| Frequency | Signal frequency | MHz | 907 MHz | Set based on your region. |
| Antenna Gain | Vertical gain of the antenna | dBi | 2.15 dBi | Isotropic antenna assumed by default, applies to most meshtastic devices. |
Refer to the Meshtastic region settings (https://meshtastic.org/docs/getting-started/initial-config/) and use the correct transmit power and frequency for your location.
| Parameter | Meaning | Units | Default Value | Notes |
|---|---|---|---|---|
| Sensitivity | Minimum signal strength the receiver can detect | dBm | -130 dBm | Default based on the LongFast channel. |
| Height AGL | Height of the receiver above ground level | Meters | 1.0 m | Typical handheld receiver height. |
| Antenna Gain | Gain of the receiver's antenna | dBi | 2.15 dBi | Assumes an isotropic antenna. |
| Cable Loss | Loss in signal strength due to cable attenuation | dB | 2 dB | Assumes a 2 dB additional cable loss. |
Choose your receiver sensitivity based on the channel (defaults to LongFast). It is realistic to reduce the theoretical values to account for radio noise in the local environment. This is particularly important in urban regions, where the Meshtastic channels are shared with other services.
| Channel Setting | Spreading Factor (SF) | Bandwidth (BW) | Estimated Sensitivity |
|---|---|---|---|
| SHORT_TURBO | SF7 | 500 kHz | ~ -126 dBm |
| SHORT_FAST | SF7 | 250 kHz | ~ -129 dBm |
| SHORT_SLOW | SF8 | 250 kHz | ~ -131.5 dBm |
| MEDIUM_FAST | SF9 | 250 kHz | ~ -134 dBm |
| MEDIUM_SLOW | SF10 | 250 kHz | ~ -136.5 dBm |
| LONG_FAST | SF11 | 250 kHz | ~ -139 dBm |
| LONG_MODERATE | SF11 | 125 kHz | ~ -142 dBm |
| LONG_SLOW | SF12 | 125 kHz | ~ -144.5 dBm |
| VERY_LONG_SLOW | SF12 | 62.5 kHz | ~ -147.5 dBm |
Using the RX Boosted Gain feature on devices which have the SX1262 chipset will result in improved sensitivies. Refer to the Semtech datasheet: https://www.semtech.com/products/wireless-rf/lora-connect/sx1262.
| Parameter | Meaning | Units | Default Value | Range |
|---|---|---|---|---|
| Radio Climate | Radio propagation environment. | Text | Continental Temperate | Equatorial, Continental Subtropical, Maritime Subtropical, Desert, Continental Temperate, Maritime Temperate Land, Maritime Temperate Sea |
| Polarization | Signal polarization. | Text | Vertical | Horizontal, Vertical |
| Clutter Height | Average height of ground clutter (e.g., trees, buildings). | Meters | 0 | >= 0 |
| Ground Conductivity | Conductivity of the ground. | S/m | 0.005 | >= 0 |
| Atmosphere Bending | Atmospheric bending constant. | N-units | 301.0 | >= 0 |
For most applications, do not alter the Ground Conductivity or Atmospheric Bending values. See the description and source of the Longely-Rice model here for details: https://github.com/NTIA/itm.
| Parameter | Meaning | Units | Default Value | Range |
|---|---|---|---|---|
| Situation Fraction | Percentage of locations where signal prediction is valid. | Percent | 50 | > 1, <= 100 |
| Time Fraction | Percentage of times where signal prediction is valid. | Percent | 90 | > 1, <= 100 |
| Max Range | Maximum simulation distance. | Kilometers | 30 | >= 1 |
Maximum simulation distances greater than 50 kilometers will result in longer computation times. We request that you use the minimum value posssible for your application to be respectful of shared compute resources.
Situation and time fractions of 90% have been found to be practical in real world applications using Meshtastic devices.