How to Work International Space Station Using APRS Packet Radio?

How to Work International Space Station Using APRS Packet Radio?

APRS stands for Automatic Packet Reporting System and serves as a digital communications channel for Ham radio, using a digipeater. Packet radio digipeater on the International Space Station works on 145.825 MHz FM. Any 2m VHF FM radio will be able to receive this signal. Quarter wave ground plane antenna which has a high angle of radiation works better than large colinears as their radiation pattern is concentrated at the horizon. International Space Station is above 15 degrees elevation for most of a pass and hence an antenna with a high angle of radiation is better. When outdoors, a hand held 2m radio can receive the International Space Station with a quarter wave whip antenna.

Pass time of International Space Station in your region can be obtained from the link: https://www.n2yo.com/satellite/?s=25544. Packet radio contacts are usually originating from the earth stations using the Amateur Radio on International Space Station digipeater. If the specific equipment is not being used, only a special sound of the 1200 baud audio frequency shift keying (AFSK) signal will be heard from ARISS digipeater.

Soundcard of the personal computer can route the output from the computer to an interface from the line out connection. Interface transfers it to the transmit audio connection on the radio. Audio output from the radio will have to be routed through the interface to the line in of the sound card on the computer. Serial port on the computer is used to control the push to talk of the radio. Some use VOX instead. Careful adjustment of the sound drive level is needed to switch the radio to transmit. This is only a preliminary discussion of the basic setup needed. Stations whose packets have been received and digipeated by ARISS digipeater will be displayed on the map at ariss.net: http://www.ariss.net/.