Skip to main content
Calcimator

Satellite Pass Predictor Calculator

Estimate satellite pass parameters including duration, max elevation, Doppler shift, and orbital period for amateur radio satellites.

Inputs

km
°
°
°

Results

Orbital Period

100.72 min

Max Pass Duration

15.3 min

Usable Pass Duration

9.7 min

Orbits per Day14.3
Orbital Velocity7.46 km/s
Visibility Footprint3,038 km
Max Range (Horizon)3,291 km
Max Doppler (146 MHz)3.63 kHz
Est. Passes/Day6
Overhead Distance800
How to Use This Calculator
  1. Enter the satellite's orbital altitude (km) and inclination (degrees).
  2. Set your station's latitude and the minimum usable elevation angle (typically 5–15°).
  3. Review calculated orbital period (min), orbits per day, and maximum pass duration.
  4. Use usable pass duration and passes per day to plan satellite operating schedules.
  5. Higher elevation angles reduce pass duration but provide stronger signals with less multipath.

How the result changes with Orbit Altitude

Orbit AltitudeOrbital PeriodMax Pass DurationUsable Pass Duration
3,735168.51 min47.7 min38.3 min
12,698436.77 min171 min146.8 min
23,453854.3 min368.6 min321.1 min
32,4151,266.99 min566.9 min496.6 min

What each input means

Orbit Altitude
Satellite orbit altitude above Earth surface (ISS: 420 km, typical LEO: 600-1000 km)
Orbital Inclination
Orbital inclination in degrees (ISS: 51.6°, sun-sync: 97-99°)
Your Latitude
Observer latitude in degrees (positive = North)
Minimum Usable Elevation
Minimum elevation above horizon for workable pass (10-15° typical)

How this is calculated

Formula

T = 2π√(a³/μ); v = 2πa/T

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Orbit Altitude = 800, Orbital Inclination = 98, Your Latitude = 40, Minimum Usable Elevation = 10 = 4 input(s) provided
  2. Calculate Orbital Period
    Orbital Period
    100.72 = 100.72
  3. Calculate Max Pass Duration
    Max Pass Duration
    15.3 = 15.3
  4. Calculate Usable Pass Duration
    Usable Pass Duration
    9.7 = 9.7
  5. Calculate Orbits per Day
    Orbits per Day
    14.3 = 14.3
  6. Calculate Orbital Velocity
    Orbital Velocity
    7.46 = 7.46

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Amateur Radio

HF Propagation Calculator

Estimate Maximum Usable Frequency (MUF), optimum frequency, and hop count from solar flux index, time, distance, and season.

Amateur Radio

QSL Card Distance Calculator

Calculate great circle distance and bearing between two Maidenhead grid squares for QSL cards and contest logging.

Astrophysics & Astronomy

Orbital Period Calculator

Calculate orbital period using Kepler's laws. Find orbital velocity, angular velocity, and perihelion/aphelion distances.

Amateur Radio

Wire Antenna Calculator

Calculate wire length for dipole, vertical, loop, end-fed, and G5RV antennas by frequency and band. Includes height analysis.

Physics

Doppler Effect Calculator

Calculate the observed frequency when a sound source and observer are in relative motion using the Doppler effect equation.

More in Technology & Computing.