Although somebody here may set me straight, I would have to assume that our drones use some type of SINCGARS series radios. In frequency hop mode, the radios jump frequencies 111 x second. Both radios are programmed with the same hopset and are synched, so one would need the specific set of frequencies and be synched with them to "jam" the drone. What's far more disturbing is the possibility that the signals/commands were being somehow hacked or compromised before they were transmitted.
I think strong enough broadband noise could be transmitted to locally blanket all frequencies ,so hopping wouldn’t matter.If the desired signal is buried in enough noise it won’t be recoverable.Not a new idea.
I doubt the commands were hacked. Once you know the frequency range you simply jam every frequency being used in the range. With a stronger jamming signal, the commands are lost in the noise. It doesn’t matter how many times the frequency changes during the period.
There’s nothing really high tech involved.