The problem being that in order to effectively 'jam' a signal far away, antenna theory requires that a fairly significant proportion of that radio energy must be directed out the back of the 'antenna'/gun. Right into the person firing it.

That's also ignoring the fact that if the signal to a drone is lost, it's more than likely to fall out of the sky like a ton of bricks.

> That's also ignoring the fact that if the signal to a drone is lost, it's more than likely to fall out of the sky like a ton of bricks.

Consumer drones typically have well-defined and behaved signal loss behavior, which (for DJI ones at least) is even fairly configurable. Though quite often that behavior involves gaining a substantial amount of altitude (at least by default), which at an airport is actually probably worse than dropping.

I don't see why the signal has to go out the back. Otherwise dish-type antennas couldn't work. And those TV aerials would work as well pointed 180 degrees away from a signal as straight at it, which isn't true.

It's based on the antenna design. These 'jammer' devices aren't dish based; they're designed after Yagi-Uda style antennas, in the format of a 'rifle' that the user points at the drone. The radiation pattern for them is exactly as I described. [1]

[1] https://www.electronics-notes.com/images/antenna-yagi-radiat...