mesh

Calculates LoRa packet time-on-air using the Semtech AN1200.13 formula. Computes symbol duration, preamble time, payload symbol count, effective data rate, and the minimum transmission interval for 1% duty cycle compliance. Essential for capacity planning in LoRaWAN and Meshtastic mesh networks. Accepts spreading factor (SF7-SF12), bandwidth (125/250/500 kHz), coding rate (4/5-4/8), payload size, header mode, CRC, and optional low data rate optimization. Feeds airtime_ms to channel_utilization for mesh load analysis.

post/api/lora_airtime

Request

  • Base URL: https://calc.engineer
  • URL: https://calc.engineer/api/lora_airtime
  • Auth: none declared

Request body

sfnumber

LoRa spreading factor (7-12). Higher SF = longer range but slower data rate.

bw_khzunknown
crnumber

LoRa coding rate denominator (5-8). Represents 4/5 through 4/8 FEC ratio.

payload_bytesnumber required

Application payload size in bytes (0-255).

preamble_symbolsnumber

Number of preamble symbols. LoRaWAN uses 8; raw LoRa may vary.

explicit_headerboolean

Whether to use explicit header mode. True for LoRaWAN; false for implicit header.

crcboolean

Whether CRC is appended to payload. Recommended true for reliability.

low_data_rate_optimizeboolean

Enable low data rate optimization. Auto-calculated if omitted: enabled for SF >= 11 at BW 125 kHz.

Response

Computed result for lora_airtime

toolstring required
versionstring required
computed_atstring date-time required

Changes

No recorded changes to this operation across all 1 revision of this API.