waves penetrating.

[dr.power]

Hi guys,

Sorry, I would like to know if the higher frequencies are better to penetrate into the objects/ buildings and so on or the lower ones for a given power please? I want to know the response for either the mechanical (like sound) and electromagnetic waves please. Is the frequency the most important factor for penetrating or...?

Thank a bunch

 

[JimB]

Another apparently simple question with various answers.

To paraphrase the character Tuco in the film The Good the Bad and the Ugly: "There are two kinds of electromagnetic waves my friend, those that come in by the walls, and those that come in by the window"

For an electromagnetic wave to enter a building through a window, it is easier for the higher frequency to enter through the window, assuming that the glass is just simple glass and not something with an exotic conductive coating.
If the building is made of metal, the window behaves like a waveguide, and below a certain frequency (the cut-off frequency) the signal attenuation is very high.
So for the window the higher the frequency the more signal will get through (within limits).

Look here for more info about waveguide cut-off

The walls however, depending on what they are made from, will generally have a higher attenuation at higher frequencies.
Normal building materials, brick, stone etc, exhibit high attenuation at high frequencies.
A metal building will exhibit high attenuation at most frequencies, assuming that the metal sheets are well bonded together electrically.

JimB

 

[davenn]

The walls however, depending on what they are made from, will generally have a higher attenuation at higher frequencies.
Normal building materials, brick, stone etc, exhibit high attenuation at high frequencies.
A metal building will exhibit high attenuation at most frequencies, assuming that the metal sheets are well bonded together electrically.

JimB

That goes for sound as well

Dr power ... stop and think a moment, when it comes to sound what is it that you hear from your neighbours house with their loud stereo, or the car sitting next to you at the lights ??

You hear the low freq thump thump of the bass, all the higher freq's have been severely attenuated

cheers
Dave