Re: [Phys-l] remotes

[curtis osterhoudt <flutzpah@yahoo.com>]

When one is doing modulations, especially with modern, chip-encoded signal transfer, a "unique frequency" doesn't make much sense. Most TV or garage door remotes operate either with IR band or VLF band radio carriers, with encoded signals on top of those. See http://en.wikipedia.org/wiki/Remote_control#Technique . 

 
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> ________________________________
> From: Anthony Lapinski <Anthony_Lapinski@pds.org>
> To: phys-l@carnot.physics.buffalo.edu
> Sent: Friday, November 4, 2011 2:16 PM
> Subject: Re: [Phys-l] remotes
>
> Thanks for this useful info.
>
> I assume every auto remote, like every TV remote, has a unique frequency
> so that you can only open your car?
>
>
> Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu> writes:
> > Auto remotes use radio frequencies, typically 315 mHz or 434 mHz.  These
> > are 
> > in the microwave part of the spectrum, not IR.
> >
> > From: Anthony Lapinski
> > Sent: Friday, November 04, 2011 3:43 PM
> > To: tap-l@lists.ncsu.edu ; phys-l@carnot.physics.buffalo.edu
> > Subject: [Phys-l] remotes
> > I'm teaching about EM waves in astronomy and atmospheric absorption. I use
> > a remote control, solar cell, and Radio Shack amp/speaker to show that
> > remotes give IR pulses. These waves are partially blocked by a black
> > plastic bag and almost totally blocked by white paper or aluminum foil.
> > They go right through wax paper, clear plastic, and a metal screen.
> >
> > Does anyone know the frequency (wavelength) range for typical remote
> > controls (for radios, TVs, DVD players, etc.)?
> >
> > On a related note, my car remote pulses go through walls. Are these waves
> > similar to those for remotes I mentioned earlier, or is it in a different
> > part of the EM spectrum? I have not tried my shields with my car remote
> > yet.
> >
> > Any other demos that can be done with these remotes?
> >
> > _______________________________________________
> > Forum for Physics Educators
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> > Bob Sciamanda
> > Physics, Edinboro Univ of PA (Em)
> > treborsci@verizon.net
> > http://mysite.verizon.net/res12merh/ 
> > _______________________________________________
> > Forum for Physics Educators
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>
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