The UAVs have two alternative systems for communication.
Line of sight radio :
In the military C-Band 500 - 1000 MHz that can be jammed with simple spark-gap radio
Satellite communication :
In the Ku-Band between 10.95 - 14.5 GHz, and the satellite can be jammed.
The Uplink-Band to the satellite is 13.75 - 14.5 GHz
The Downlink-Band from the satellite is 10.95 - 12.75 GHz
And you should jam the Uplink frequencies with a jammer directed at the satellite.
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