Learn Italian: Il drone è al di fuori del raggio del segnale. - The drone is outside the range of the signal.

al di fuori is a complex spatial preposition meaning outside. When followed by a noun like raggio, it must be linked using the preposition di. Since raggio takes the masculine article il, they combine to form the articulated preposition del (di + il).

Could I just use fuori by itself instead of the whole al di fuori structure?

Yes, but the linking preposition changes. If you just use fuori, it pairs with da, so you would say fuori dal raggio. Using al di fuori pairs with di (making it al di fuori del raggio) and sounds slightly more formal, often used to emphasize the exact boundary of the signal.

Is raggio the standard word for range in Italian?

In the context of signals, radar, or a radius of action, yes. Its literal translation is radius or ray (as in a ray of light, un raggio di sole). If you were talking about a range of products or choices, however, you would use a different word, like gamma.

Why is it del segnale and not just di segnale?