hmm the reciever would be pretty easy to make its just that you need to amplify it..hmmm..
however, I've seen baby monitors that could pick up football games , so I would take a baby monitor and find which pot or coil ( if any ) I need to turn to change the recieving. Play around with that and thats it. Then work your way up from that!
Side note: a friend of mine once bought a 5 dollar radio , opened it up right in front of me and tuned the coil in there to pick up radio waves from the airport, all in five minutes. It was really cool we could hear the ground based transmissions of the airport!