Remote Locking Device into Sonic Switch Help Please

Can anyone help please.

I want to use a Remote locking device like you use to lock your car door to switch on and off a power supply to a small transmitter which is difficult to access once in place (Nesting Box).

Is it just a case of modifying the relay within the locking mechanism to just turn the power on and off instead of activating a door lock. If it is, could someone please help with a diagram, as usual size is important! Smaller the better please.

Another question is how easy is it to boost the RC frequency within the activator. I need a fairly long range and may not always have line of sight. What sort of obstacles would the signal pass through.

Thanks for any help

You could use a remote starter as your Transmitter and Reciever. The range on most is about 350 feet.
The only problem I see is the relay would have to stay on while the lock-out was operating. This could Potentially run your Battery Down unless you use some kind of toggle Flip Flop as a Relay switcher.
I will see what I can come up with.