Key Fob Conundrum..........................calling ScienceBoy.

[Slime]

Interesting query regarding car key fob blipper things.
I've been aware of this for a few years but never knew the reason why this happens.
My car blipper works from about 30ft away when held out in front of me, but, when I operate it from by the side of my head the operating distance almost doubles.
Why is this ScienceBoy.
Thanks,

Slime.

P.S. If anyone thinks I'm mad, try it, you'll be amazed.

 

[Wolfman]

Yep you are correct this works but not sure why and it needs to be close to the head / chin etc

Spooky

 

[chris661]

Its like holding onto a radio antennae. They work on the same principal.

 

[Slime]

Its like holding onto a radio antennae. They work on the same principal.

Que?

 

[chris661]

Radio waves, your body then becomes part of the antennae.

 

[DappaDonDave]

Radio waves, your body then becomes part of the antennae.

Exactly...works a treat with all my cars which had central locking.

 

[Slime]

Radio waves, your body then becomes part of the antennae.

But only when held close to ones' head?

 

[chris661]

But only when held close to ones' head?

yer heid is full o water!

Dunno, you ever tried it anywhere else?

 

[Slime]

yer heid is full o water!

Dunno, you ever tried it anywhere else?

Only when handheld in front of me or by my side!

 

[sawtooth]

Could be fresnel zone clearance from the ground.

 

[Slime]

Could be fresnel zone clearance from the ground.

I thought about that, obviously, but there are no objects in the way to deflect the signals.

 

[JustOne]

Would it work with my keys in my pocket if I was nursing a semi?

 

[sawtooth]

You can have clear line of sight but the ground can still interfere with the RF signal. The fresnel zone is a kind of bulge in the RF signal above and below the LOS. That bulge needs to be clear from obstructions, buildings, trees, etc but also the ground.

I'm not sure this is the reason with key fobs but its a possibility.



.

 

[Slime]

Would it work with my keys in my pocket if I was nursing a semi?

It depends on who's semi you were nursing and how you were nursing it .

 

[richart]

They tested this on Top Gear years ago, and no one could come up with a scientific reason for it.

 

[Smiffy]

Would it work with my keys in my pocket if I was nursing a semi?

Isn't that 90% of the time James??????

You're like the butchers dog. All ribs and cock.

 

[ScienceBoy]

This is more one for the physics teachers, a class I hated as it had too much maths.

I am more biology and chemistry, as for the answer, I would hazard a guess that those before me are right and it has something to do with this friend zone thing.