There's no good way to reliably limit the range of a wireless signal like this. A sufficiently sensitive receiver will always be able to eavesdrop from a dista

There's no good way to reliably limit the range of a wireless signal like this. A sufficiently sensitive receiver will always be able to eavesdrop from a distance far greater than that in the design use-case. If we don't want the signal intercepted, the answer is stronger encryption. That said, any potential vulnerability here appears to mostly spring from the remote control functionality, more than the remote reporting functionality. Here again, encryption is the answer.