may be legal?
"Un fortunate jamming device are illegal to posses and use in the US."
Possess? I think you can possess any kind of radio device you want, as long as you don't use it. Use? The blanket "it's illegal to use" is usually talking about cellular band jammers. The rules for these bands remote controls use? Typically fcc rules say devices must tolerate interference, and must not intentionally generate interfeference. But in most bands, there's also a power limit where if you are below that limit, your device can do whatever it wants. It's entirely possible you could jam a drone if it got close enough AND stay fully within FCC regulations.