Reference Plane / Episode 1

NTN physics explorer

Move the satellite, sweep the pass, turn on the rain.

Scale view 550 km ×1.09 Earth radius Slant range 550 km
Satellite altitude
550km

Orbital velocity

7,588m/s
200 kmLEOMEOGEO50,000 km
Frequency & Pass position

Carrier frequency

Pass position

90°zenith
5° rising90° zenith175° setting

Delay

Round-trip

3.67ms

Slant range: 550 km

Cell tower (10 km): 0.07 ms RTT

RTT = 2·d_slant / c

Path Loss

153dB

FSPL 153.3 + rain 0.0 dB

Required sat gain: 25 dBi

Rain rate

0 mm/hr

FSPL = 20·log(4π·d·f/c) + A_rain

Doppler

0Hz

Max during pass: 47 kHz

rising TCA setting

Approach is +, recede is −. GEO is flat.

Δf = f · v_rel · cos(ε) / c

Theoretical maximum data rate
9.0Mbps
HARQ processes
no protocol cap

Shannon × HARQ pipeline factor. Real systems reach roughly 30 percent. C = B · log₂(1 + SNR) · min(1, N·t_slot/RTT).

SNR

4 dB

Channel BW

5 MHz

Sat EIRP

50 dBm

Terminal

Handset, 0 dBi