Why does a remote car key work when held to your head/body?

I was trying to unlock my car with a keyfob, but I was out of range. A friend of mine said that I have to hold the transmitter next to my head. It worked, so I tried the following later that day: Walked away from the car until I was out of range Put key next to my head (it worked) Put key on my chest (it worked) Put key on my leg (didn't work) So first I thought it has to do with height of the transmitter. But I am out of range if I use the key at the same height as my head but not right next to my head. Same applies when my key is at the same height as my chest. So it has nothing to do with height (as it appears). Then I thought, my body is acting like an antenna, but how is that possible if I am holding the key? Why would it only amplify the signal if I hold it against my head and not if I simply hold it into my hand? Here's a vid of Top Gear demonstrating it.