Amateur Radio operators are very fortunate, in that as well as having the use of amateur radio repeaters to extend their range, they also have the use of Low Earth Orbiting satellites(LEOs) that are built and maintained by amateur radio enthusiasts. These satellites operate in the VHF and UHF amateur bands, and can allow stations to communicate with each other at distances far greater than normally possible. One of the most popular satellites used today is AO-51.
AO-51 was launched on the 29th of June 2004 from Baikonur Cosmodrome, Kazakhstan, and it really is one of the easiest satellites to work through.
The uplink frequency (the frequency one transmits on) is in the 2M band (145.920MHz 67.0Hz CTCSS tone), and the downlink frequency (the receiver frequency) is in the 70 cms band (453.300 no tone). First of all we need to find out where and when the satellite will appear at your location. Fortunately, this information is very easy to find.Go to the heavens-above website, and type in your location details to get a list of passes at your location.
Listen on your radio at the time the satellite is about to appear over the horizon, but begin by listening 5 kHz above 453.300MHz.Once the signal becomes clear, start tuning down in 1 kHz increments to get the clearest signal.This is to allow for the doppler effect. Once you hear the satellite, you will be able to put a call out on the uplink frequency, and with a little bit of luck you should hear your own signal relayed back to you.
Recently launched from the International Space Station in February 2011, is a new satellite from North America called ARISSat-1. Uplink is between 435.740-455.760MHz, and the downlink is between 145.918-145.958MHz. As well as voice operations, ARISSat-1 has four SSTV (Slow Scan TV) cameras onboard. Images will be stored and the transmitted in color using Robot36 mode under the callsign RS01S.
Information regarding passes at your location after launch, will be found in this instance by looking on the AMSAT North America website. Although transmitted power from amateur radio satellites is very low (of the order of about 500 mW to 1 Watt), it is still possible to hear and work through them using a handheld transceiver with its built-in Whip antenna.
Remember to tilt your antenna, so that it’s perpendicular to the satellite, for better reception. Amateur satellites can be a boon to Amateurs who are restricted to operating on the V/UHF bands, and can allow intercontinental contacts to take place that wouldn’t otherwise be possible.