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Author Topic: Why does a key fob work better against the temple ?  (Read 17766 times)

Offline neilep

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Dr Beav , discussing the nature of a cars key fob said in a recent thread that:

It'll work over even greater distance if you hold it against your temple when you use it. This was tested on Top Gear and the presenters were stunned that it's true.

Why is this ?


Could it be as simple as the fact that you have raised the key fob higher and so the signal has less obstruction to reach the car ?......and the ' temple' is just a red herring ?




 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #1 on: 22/02/2008 08:48:53 »
I have scoured the net trying to find the answer, as a moderator on a certain site that shall remain nameless asked me to write a litle bit about it as a piece of science that could take place in that room in your house where you do most of your cooking.

Unfortunately I have found no answer to it.
 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #2 on: 22/02/2008 08:49:51 »
It's not just that you're holding the fob higher. That was tried without holding it against the temple & it didn't work.

I would put a link to the video but it's on YouTube.
« Last Edit: 22/02/2008 08:52:44 by DoctorBeaver »
 

Offline Soul Surfer

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Why does a key fob work better against the temple ?
« Reply #3 on: 22/02/2008 10:44:22 »
You are probably using your body as an antenna or counterpoise for the signal and enabling the key fob which is probably fery much smaller than a wavelength long to radiate better.  I am not sure what frequency car key fobs use nowadays but thees a fair chance its in the fre for all region around 2.4Ghz where most of the low power radio devices work nowadays.

Checking up it seems that the frequency is likely to be lower around 400MHZ  that's a wavelength of about one metre so the body would act as quite a good aerial at that frequency
« Last Edit: 22/02/2008 10:52:12 by Soul Surfer »
 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #4 on: 22/02/2008 20:19:50 »
That certainly sounds feasible.
 

lyner

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Why does a key fob work better against the temple ?
« Reply #5 on: 24/02/2008 22:42:01 »
Adding your (relatively long) body as a part of the radiating element will change the radiation pattern from 'fairly omnidirectional' (which is more useful) to one with more 'gain'in random directions. As your body moves around, these 'lobes' wave around and may point in the direction of your distant car.
 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #6 on: 24/02/2008 22:50:35 »
My lobes do NOT wave around  [:0]
 

Offline Karen W.

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Why does a key fob work better against the temple ?
« Reply #7 on: 25/02/2008 09:22:03 »
You are probably using your body as an antenna or counterpoise for the signal and enabling the key fob which is probably fery much smaller than a wavelength long to radiate better.  I am not sure what frequency car key fobs use nowadays but thees a fair chance its in the fre for all region around 2.4Ghz where most of the low power radio devices work nowadays.

Checking up it seems that the frequency is likely to be lower around 400MHZ  that's a wavelength of about one metre so the body would act as quite a good aerial at that frequency

I quite agree with the body as a antenna as it brings to mind  my grandmas old zenith black and white TV... I remember having to stand close by it and hold my hand on the antenna when something important was on .. Normally we wrapped foil on the antenna and I have done that with old Rabbit ears in my sons trailer to increase the reception.. LOL.. But when there was no foil available and less then perfect reception, I could stand within a couple feet of the tv and hold the top of one side of the rabbit ears and immediately become a conductor of better reception and we would have crystal clear reception.. as soon as I turned loose the TV would go crazy.. It was hard job and I always got stuck when something good was on and reception was poor! LOL

There must be a similar thing with the key fob that uses the energy from us or could it be that our bodies are mostly water and water conducts electrical impulses and such really well.. so perhaps thats why we are better conductors.. Could that be even close to accurate..????

What about You being the ground for the fob or the antenna? Wouldn't we be an effective ground, by absorbing the interference that may be in the building.. he did say he was inside right? That would certainly improve the reception..

I do believe though if he were outside it might make it worse because most regular antennas kinda detune and loose their efficiency while coming in contact with radio frequency or such and absorbing into our tissue layers like our hands or heads etc. Wouldn't being inside kind of block interference excess noise etc...Static?


.
« Last Edit: 25/02/2008 09:52:50 by Karen W. »
 

lyner

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Why does a key fob work better against the temple ?
« Reply #8 on: 25/02/2008 09:25:13 »
My lobes do NOT wave around  [:0]
That's a big relief all round!
 

Offline Karen W.

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Why does a key fob work better against the temple ?
« Reply #9 on: 25/02/2008 09:28:23 »
This is kinda what I meant!

mode=related&search=
 

lyner

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Why does a key fob work better against the temple ?
« Reply #10 on: 25/02/2008 09:33:05 »
Quote
my grandmas old zenith black and white TV...
There is a story of a TV engineer who found a sausage in the back of a faulty TV. The reason given was that the owner found that it worked better when he put his finger in ' just the right spot'. He replaced his finger with a sausage in the same place and could then sit and watch TV in comfort.

In the old days of 'positive modulation' TV systems (UK 405 line system, for example) 'frame roll' was very common when the signal strength was poor. There was a tale of a service engineer who was being tightly scrutinised and criticised by a fussy owner. He adjusted the frame hold control to start the picture rolling and asked the owner to choose which of the rolling pictures he preferred and the engineer stopped the rolling. Having made his own choice, the owner was satisfied and let the serviceman leave.
 

Offline Karen W.

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Why does a key fob work better against the temple ?
« Reply #11 on: 25/02/2008 09:47:53 »
THats pretty good... LOL..Sorry I posted and then added somme to my post as I had it in word and missed part of it when coping and pasting.. the rest is in the other post!


That old zenith rolled like crazy! I had it for years.. Thats so funny... Make it roll and let him choose.. LOL We give kids that choice to and they are always happy knowing it was their choice not ours! LOL..Very cool story..
 

Offline Make it Lady

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Why does a key fob work better against the temple ?
« Reply #12 on: 25/02/2008 18:01:03 »
I think it is because Clarkson has a metal head. That would explain a lot about his attitude.

Someone told me that you could open your car by clicking your fob near a mobile phone connected to a phone near your car. This can't be right can it?

Isn't there a song about flapping Lobes. Do your ears hang low, can you shake them too and throw, can you tie um in a knot, can you tie um in a bow? I think it was ears.
« Last Edit: 25/02/2008 18:04:17 by Make it Lady »
 

Offline Karen W.

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Why does a key fob work better against the temple ?
« Reply #13 on: 25/02/2008 18:22:42 »
Do your ears hang low..... do they wobble to and fro.... can you tie them in a knot? Can you tie them in a bow? Can.. you throw them or'e your shoulder.. like a continental soldier?...Do your ears hang low? LOL One of my favorites!!
« Last Edit: 25/02/2008 18:24:15 by Karen W. »
 

lyner

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Why does a key fob work better against the temple ?
« Reply #14 on: 25/02/2008 19:25:26 »
Only, when I was at School it wasn't ears.
(It was an all-boys school)
 

Offline Karen W.

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Why does a key fob work better against the temple ?
« Reply #15 on: 25/02/2008 20:39:55 »
thats funny, I once sang it to a friend where I
substituted  a couple female body parts for the ears....Lol.... I had it stuck in my head and somehow getting it out fixed theurge to blast it out involume throughout the house!!
LOL... I felt silly... and well I should have!!! Al though it did make me giggle !!!
 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #16 on: 26/02/2008 08:00:08 »
I think it is because Clarkson has a metal head. That would explain a lot about his attitude.

Don't talk about my near neighbour like that!

Someone told me that you could open your car by clicking your fob near a mobile phone connected to a phone near your car. This can't be right can it?

There have been a lot of rumours about this but apparently it is a myth. Key fobs, it seems, work on a frequency that mobile phones can't handle.

Isn't there a song about flapping Lobes. Do your ears hang low, can you shake them too and throw, can you tie um in a knot, can you tie um in a bow? I think it was ears.

No comment  :D
 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #17 on: 26/02/2008 08:02:24 »
thats funny, I once sang it to a friend where I
substituted  a couple female body parts for the ears....Lol.... I had it stuck in my head and somehow getting it out fixed theurge to blast it out involume throughout the house!!
LOL... I felt silly... and well I should have!!! Al though it did make me giggle !!!

 [:0]
 

Offline Make it Lady

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Why does a key fob work better against the temple ?
« Reply #18 on: 26/02/2008 22:26:39 »
I thought it was a myth. I'll kill my friend, he is always telling me about these weird experiments because he knows that as I'm more curious that a whole box of cats, that I will try them out. Then he sits back and watches me do all the silly stuff to no avail. If anyone has a silly experiment I can get him to do, I'll be very grateful. He is quite smart so it would have to be very good!
And Karen, do they hang low?
 

Offline DoctorBeaver

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Why does a key fob work better against the temple ?
« Reply #19 on: 26/02/2008 23:14:44 »
They Hang Low? Wasn't he a Chinese acrobat?  :D
 

lyner

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Why does a key fob work better against the temple ?
« Reply #20 on: 27/02/2008 07:52:55 »
Quote
Someone told me that you could open your car by clicking your fob near a mobile phone connected to a phone near your car. This can't be right can it?
Something like that couldn't happen by chance. It would have to be built into both systems when they were designed. Why would they do that? It's a daft idea.
 

Offline Make it Lady

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Why does a key fob work better against the temple ?
« Reply #21 on: 27/02/2008 17:32:45 »
Yes but I'm gullible and not a physicist or techno girl
 

Offline Karen W.

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Why does a key fob work better against the temple ?
« Reply #22 on: 27/02/2008 21:17:01 »
I thought it was a myth. I'll kill my friend, he is always telling me about these weird experiments because he knows that as I'm more curious that a whole box of cats, that I will try them out. Then he sits back and watches me do all the silly stuff to no avail. If anyone has a silly experiment I can get him to do, I'll be very grateful. He is quite smart so it would have to be very good!
And Karen, do they hang low?

Why Yes yes they do as a matter of fact!!!! LOL.. Gravity has a way of doing that you know!!! lol
 

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Why does a key fob work better against the temple ?
« Reply #22 on: 27/02/2008 21:17:01 »

 

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