80k Hops per Second Measurement Confirm Starlink Up/Downlink Channel Pairing

A hardware-controlled setup using an AD9361 software-defined radio raises channel-scanning speed from 10,000 to 80,000 hops per second. It switches channels every 12.5 microseconds, scanning all eight Starlink channels in 100 microseconds. Although the radio’s specifications give a longer settling time, the experiment finds that 10 microseconds is enough to measure stable in-band signal energy, leaving 2.5 microseconds for integration. The faster system reproduces behavior seen in earlier software-controlled measurements, supporting the reliability of the method. Using two radios and satellite-TV low-noise block converters, the measurements track terminal uplink transmissions and leakage from its receiver’s local oscillator.

The central finding is that Starlink terminals consistently use the same channel number for uplink and downlink, despite the two directions operating at different frequencies: eight 500 MHz downlink channels span 10.7-12.7 GHz, while eight 62.5 MHz uplink channels span 14.0-14.5 GHz. No mismatched channel numbers appeared during ten minutes of observation. The setup also detects both transmissions and receiver leakage several meters from a consumer terminal, even with an LNB pointed away from the antenna’s rear, suggesting measurable off-axis radiation beyond the intended narrow beam. A real-time display shows channel activity, including denser uplink transmission during a speed test, indicating the signals reflect actual terminal operation rather than interference.