About ISS.guru

Helping amateur radio operators connect with the International Space Station

Why ISS.guru Exists

ISS.guru was created specifically for amateur radio operators who want to communicate through the International Space Station's amateur radio repeater system.

The ISS carries amateur radio equipment as part of the ARISS (Amateur Radio on the International Space Station) program. This allows ham radio operators on Earth to make contact with astronauts aboard the station and communicate with other operators via the ISS repeater.

Timing is everything in satellite communications. You need to know exactly when the ISS will be above your horizon, at what elevation angle, and in which direction to point your antenna. ISS.guru provides precise pass predictions to help you plan your contacts and maximize your chances of successful communication.

ISS Amateur Radio Operations

Current Frequencies

Uplink: 145.990 MHz
Downlink: 145.800 MHz
Mode: FM Voice

Note: Frequencies may change. Always check current ARISS status before operating.

Operating Tips

  • Use FM mode with 5 kHz deviation
  • Keep transmissions brief and clear
  • Account for Doppler shift during the pass
  • Higher elevation passes work best

How Pass Predictions Help

Our pass predictions calculate when the ISS will be visible from your location, providing essential information for successful amateur radio contacts:

Rise Time

When the ISS appears above your horizon

Max Elevation

Highest point in the sky - best signal strength

Set Time

When the ISS disappears below horizon

Higher elevation passes (above 20°) typically provide better signal quality and longer communication windows. The ISS is only audible when it's above your radio horizon, typically lasting 2-8 minutes per pass.

Getting Started

1

Find Your Location

Use our location finder or browse cities to get pass predictions for your area.

2

Plan Your Operation

Review upcoming passes and choose ones with good elevation angles. Learn how to use pass data.

3

Make Contact

Set up your equipment and try to make contact during the predicted pass times. 73!

Useful Links