I had a former boss convince me that if he held his keyfob pointing towards and touching his chin, he could increase the range at which he could unlock his car. I thought this might have been due to the orientation of the keyfobs sending unit, and possibly his height.
No, every single test that I have performed has shown that I can get a greater distance out of my keyfob by placing it under, and touching my chin. If I held the keyfob at the exact same height and orientation, it fared worse than when I “used my skull as an antenna”.
I have demonstrated this to numerous people, using who knows how many different types and makes of vehicles, and it seems to always work.
Why is this? Can a skull actually be used as an antenna?
Try it yourself. Cycle your cars alarm system until you think you’ve reached its maximum range, point the fob towards the sky until it no longer responds. Then put the fob (pointing towards the sky) right against the front of your chin. Did it respond?
It probably did. Why is this?
Every single test that I have done has seen the same effect.
AFAIK key fobs use radio waves to transmit signals, as opposed to IR or some other sort of wave. If more distance is gained by aiming the wave, or at least positioning it differently, in regards to a human chin… could a skull be a possible antenna?
I don’t know the mechanism, but I have verified the effect for myself, and I recall Clarkson demonstrating it on Top Gear.
Not sure if keyfobs are actually radio or infra-red. If they’re infra-red, it may simply be that you’re using your head as a diffuser, while if you aim your fob at a distance you may be missing the vehicle altogether with a tight beam.
I’ve verified this one myself too, by many experiments - the difference in range is a factor of three or four, so it’s quite easy to eliminate wishful thinking from the test.
I’m not sure about 'skull as antenna though - that seems to be based on the assumption that the radio signal is emitted along the key shaft - which may or may not be true. It could just be that pressing the thing under your chin means it’s in front of your body - and maybe that’s what causes the phenomenon.
Clarkson (who’s video I watched based on the above replies) demonstrated this same phenomenon by placing the keyfob at his temple (or close to it at least).
The explanation I have heard is that your voice box amplifies the signal. Certainly didn’t convince me, but I’m also at a loss to explain the phenomenon.
I know it works but I don’t really know why. I’ve heard two possible explanations. One is that the close proximity of the remote to your skull makes enough signal get coupled into your head that it effectively acts as a larger antenna. The second is that your skull is acting as a large reflector and is focusing the radio waves towards the target.
It would be interesting to put someone with a remote into an RF test chamber and see exactly what is going on.
i agree that your skull or some part of it would be acting as an antenna element, a reflector. other body parts may not work this way, it would depend on the size of a continuous body part and the distance of the remote from it, skull or jaw may just be the right thing.
Except that your skull is convex not concave and a convex surface will spread the reflected signal out, reducing focus. Unless it is the back of the head that is being used. A wooden boat can act as a good radar reflector not because the wood reflects the radar but because the shape of the displace water on the opposite side of the boat is a nice concave shape. Maybe the inside of the rear of your skull, moistened with brain goop is acting as a good reflector.
Not claiming anything one way or the other, but I do want to point out how poorly designed that Top Gear fellow’s experiment was, insofar as the transmitter was held in two very different orientations in the two test cases. Orientation will certainly make a difference, as the transmitter is far from omnidirectional.
Your skin conducts electricity. It can be used as an antenna. My WAG is that youre using the top part of your skin (head) as an antenna. Because your head is the tallest part of you, your signal seems to go out farther because its coming down from an up position as opposed to using your hand which is usually in a low position.
They used to sell cordless phones in the 1980s or 1990s which only worked when you held them in a certain way because they used your body as an antenna.
True, I asked the same question FIVE YEARS AGO. There has yet to be a conclusive explaination, and now I have my own keyfob to experiment with.
It seems to almost have been proven as a phenomenon, especially given the credibility of the variety of testers and their various circumstances. However, the actual workings and physics of it, seem to be a mystery.
The body can certainly act as an antenna. I can get noticeably better reception of a weak signal on my radio if I touch the antenna, or even if i hold my hand near to it. (In the latter case, I believe, this works because of capacitative coupling between the antenna and my hand.) I see no reason why this should not work with the transmitter in a key fob too, although I am not sure why you have to touch it to your head. I don’t know why just holding it in your hand should not be enough.
ETA: Presumably the effect with the fob depends on capacitative coupling too, as the fob’s antenna is encased in the insulating plastic case of the fob and does not make direct electrical contact with the skin.
I’ve done several experiments, and they all show the same results. This phenomenon is real.
I’m sure you have a friend or two with remote unlock keyfobs. Try it yourself, no foil hat required.
I’ve yet to hear of an Empirical test that disproves this phenomenon.
