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When a radio signal is broadcast from a transmitter, some of it disappears upwards into space and is lost. However, during certain weather conditions, the “lost” signal can be bent back ...

Deep Space Network engineers detected the faint S-band signal. The team won't reactivate the X-band transmitter until they understand the fault protection system trigger, potentially taking weeks.

This means that most ground-based transmitters will appear to have a constant frequency, much like the test signal shown above. Signals from deep space will show a drift in frequency due to the ...