Is this True?

trikz_a2

trikz_a2

Member
Received this email;

"Have you locked your keys in the car?

Does your car have remote keyless entry? This may come in handy someday. Good reason to own a cell phone: If you lock your keys in the car and the spare keys are at home, call someone at home on their mobile phone from your cell phone.
Hold your cell phone about a foot from your car door and have the person at your home press the unlock button, holding it near the mobile phone on their end. Your car will unlock. Saves someone from having to drive your keys to you. Distance is no object. You could be hundreds of miles away, and if you can reach someone who has the other 'remote' for your car, you can unlock the doors (or the trunk).
> Editor's Note: It works fine! We tried it out and it unlocked our car over a mobile phone!'"

Doubt this works, any1 tried or heard this before?
 
Isn't the key fob working in ultrasonic frequency? If it is, it simply can't be done. Good Car audio speakers work from 40Hz to say 20khz subs mids tweeters as a general guide, and your hearing frequency is a little wider than this and way, way, way beyond that ultrasound. So are they trying to say the little mobile phone mic can pick up ultrasonic frequency sound and then send it down a tiny low quality speaker 10mm in ultrasonic frequency from the phone?

That is funny:D

Sorry just watched the last youtube, should have done this before i replied, would have saved me time
 
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But Audi systems can get up to 30000Hz or more but no one can hear it! So it is possible that a mobile phonecould transmit more than sound you can hear. But the remote will not use any sound signal. As I said, electromagneticle waves... like radio broadcasting.
 
I'm not sure a poor little phone speaker would get anywhere near 30000khz, i know you can't hear much more than 20000khz but expensive audio speakers can't/don't get that high so I doubt a phone speaker could. Skipton works in sound or the electrical industry i think perhaps he could tell us?
 
I think this is b*ll*cks to be frank:

The microphone in a mobile is quite capable of pcking up signals up to 100kHz, but the signal from the key fob is sent at 433MHz, that's 433000kHz, only 4000 times higher than the mic is capable of picking up!

Now even if it could pick up the signal, the speaker in the mobile can probably not emit anything much above 40kHz and even that will be a harmonic.

So, it's totally unfeasible to expect it to work.


BUT

Having said that, why does holding the key fob to your head double the effective range!!!???

Cheers,

Mike
 
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