LEO Amateur Satellites

Saudi-Sat SO-50

SO-50 hosts various experiments, including a mode J FM amateur repeater operating at 145.850 MHz uplink and 436.795 MHz downlink. This repeater is available to amateur radio operators worldwide as long as power allows. To activate it on demand, you need a 67.0 Hz PL tone on the uplink. There’s also a 10-minute timer that must be armed by transmitting a 2-second carrier with a 74.4 Hz PL tone.

The repeater features a compact VHF receiver with a sensitivity of -124 dBm and a 15 kHz IF bandwidth. Its receive antenna is a 1/4 wave vertical located at the top corner of the spacecraft. The received audio is filtered, conditioned, and gated in the control electronics before being sent to the 250 mW UHF transmitter. The downlink antenna, a 1/4 wave mounted at the bottom corner, is tilted inward at a 45-degree angle.

Memory NameTransmitReceiveCTCSS Tone
SO-50 ON145.850 MHzN/A – Timer Activation74.4 Hz
SO-50 1145.850 MHz436.805 MHz67 Hz
SO-50 2145.850 MHz436.800 MHz67 Hz
SO-50 3145.850 MHz436.795 MHz67 Hz
SO-50 4145.850 MHz436.790 MHz67 Hz
SO-50 5145.850 MHz436.785 MHz67 Hz

Sarah Rose

An avid amateur radio operator and linux fan girl.