Technical analysis and engineering reference.
A 100 milliwatt (+20 dBm) transmitter on Earth attempting to reach a satellite at a slant range of 1,000 kilometers experiences over 150 dB of free-space path loss. If this small power is distributed across a wide 20 MHz cellular channel, the signal sinks tens of decibels below thermal noise, making detection impossible without a massive satellite dish.
By reducing the channel bandwidth from 180 kHz down to 3.75 kHz, NTNSensors achieves an 18 dB gain in Power Spectral Density (PSD): - The same 100 mW of transmitter energy is packed into a microscopic spectral window. - The satellite receiver applies high-resolution digital filtering, excluding out-of-band noise. - This allows humble omnidirectional patch antennas etched onto printed circuit boards to successfully close link budgets with LEO satellites without any physical pointing requirements.
Sensors deployed across maritime shipping containers operate for over a decade on two standard AA lithium batteries, automatically broadcasting location, tilt, and shock alerts once every 12 hours.