Communication Basics #26 Worked Example: Satellite GEO Delay

Instructor: Dr. Süleyman Burak ÇELİK

First final preparation video in the Communication Basics series. Classic GEO satellite delay problem — in light mode, step by step. 36,000 km geosync orbit, c = 3 × 10⁸ m/s. One-way: t = D/c = 120 ms. End-to-end (Tx → Sat → Rx) is 240 ms, round-trip 480 ms. ITU-T G.114: under 150 ms imperceptible, 150–400 ms noticeable, 400 ms+ problematic. GEO 240 ms end-to-end — fine for TV/data, not for real-time voice. Close: LEO/MEO/GEO comparison. Starlink ~3 ms, GPS ~67 ms, GEO ~120 ms. Altitude = latency. This is why Starlink deploys thousands of LEO satellites — to break the GEO latency wall.