AO-27 transmits with a power output of 0.5 W into a quarter-wavelength whip antenna. Satellites are approximately 500 miles (800 km) distant when directly overhead and over 2,000 miles (3,200 km) distant when near the horizon. For use on AO-27 with a half-wavelength whip, your receiver sensitivity at 436 MHz should be at least 0.18 uV for 12 dB SINAD, which corresponds to the approximate signal strength of AO-27 at 10 degrees elevation when your whip antenna is correctly positioned for the polarization of the incoming signal. At the horizon, AO-27’s signal strength, under similar conditions, is approximately 0.13 uV. Most modern, high-quality amateur radio transceivers will meet these specifications if designed to operate at this frequency (i.e., without modifications). Most scanners, and most radios which have had to be modified to cover 436 MHz, will not.
AO-27 transmits FM on about 436.795 MHz, plus/minus Doppler shift of up to 10 kHz on either side. Their uplink frequency is 145.850 MHz, plus/minus Doppler corrections of up to approximately 3.4 kHz.
by Ray Soifer, W2RS
The Spring edition of the AMSAT-UK colour A4 newsletter OSCAR News is being posted to members this week.
In this issue
– Dick Daniels W4PUJ SK
– VEGA Maiden Flight Report
– My way to solve the TLE lottery by Mike DK3WN
– Your Spacecraft recording wanted, urgently
– Getting back on the Satellites by Andrew Sellers G8TZJ
– FUNcube satellite project update
– The Clive Wallis G3CWV Column
– A Swiss satellite to tackle space debris
– ARISSat-1/KEDR goes silent
– FUNcube satellite models part 2
– KickSat – your personal spacecraft in space!
We are looking for articles relating to ham radio satellites or anything related to ham radio in space. This can be anything from tips on working your favorite satellite
to using satellite tracking software or your latest project.
Qtmm is a simple AFSK1200 decoder that uses the computer’s sound card for input. It can be used to decode packet radio, APRS and telemetry from OSCAR and Cubesats.
Testing shows a good performance in monitoring the International space station APRS Beacon. More @ Qtmm soundcard modem for decoding AFSK1200
Telemetry reception from the AO-27 amateur radio satellite, which also uses AFSK.