Material that would block/shield radio frquency signals?

Question

Anyone know some material that could shield/block radio frequency pulses (around 58kHz.) I think aluminum works a little, anyone know what the best material would be, or any other material that would come to mind?

And where I could find/buy these materials if I wanted to like make a shield at home, or any tips on how to do so.

Answer 1

58 KHz will sneak around anything, so you need to enclose whatever you are building on all sides, with the corners connected. At that frequency , the wavelength is very long (5100 meters), so you dont have to worry about seams. In other words, cracks are OK. You are basically sheilding the magnetic portion of the wave.

All entrances such as power , audio, to the box must go through filters, such as 1uF capacitors grounded very close.

To emphasize, you cannot put up a plate or even a 5 sided box to shield this frequency.

Although its the magnetic portion of the wave you need to shield, you dont need iron. Any metal will do because it's AC. Copper sheet is available from a lumber store as roofing flashing, and it can be soldered.

Answer 2

58kHz seems pretty low to be a radio frequency, unless this is the modulation rate of an RF signal on a high frequency carrier. You called these "pulses", which makes me think maybe this is the pulse repetition frequency of an RF carrier, as in the case of a radar. If that is the case, a Faraday shield/cage could work and knowing the RF carrier frequency would allow the proper material to be selected. If 58KHz is indeed the actual signal that is offending you, then ZORCH's answer above is a great one.

Maybe this is not practical, but sometimes it is easier and cost effective to shield at the SOURCE of the offensive signal. Where is this signal coming from and why is it only bothering you? Do you have sensitive equipment?

Answer 3

I'll add to Barney's good answer. The coupling at this frequency is going to be dominantly magnetic, so I prefer something ferromagnetic. And, Maxwell said that there is no field inside a conductor but in practice that is true when the thickness of the shield is 3+ times the skin depth at the frequency in question. And, for 58KHz, the skin depth calculation makes for thick copper or aluminum. But, there is also a permittivity term in the equation and you get a big boost by using something like (nobody will believe this) common galvanized steel. Like garbage cans and tin roofs. And, it is cheap, can be soldered, and can be had at any hardware store.

Answer 4

Rf Blocking Material

Answer 5

There is no such thing that will just shield radio signal in certain frequency. You did not give the detail on why you want to shield that particular frequency.

Any metal can be used to shield radio signals but it will require some technique.

That is why there are technicians.

Answer 6

what you want is called a faraday cage.

its basically a contained area , lets say a room,
put a mesh screen on all to the walls including the
ceiling and floor. the meshed screen must be smaller
then the amplitude of the rf signals. so that no signal can
pass through the holes. if the mesh screen is well grounded
then any signal that hits the mesh screen gets grounded
and no rf signal gets through..

another way to block rf signals is to deflect it off into
a different direction.

Answer 7

Are you trying to make your car invisible to radar?

Any conductor, properly grounded, should reflect electromagnetic waves. You would need some type of resistive, but not totally insulating, material for absorbing EM waves and turning them into heat.

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...RAMs are designed to attenuate or absorb microwave energy with the absorbed energy converted to heat. Microwave absorbers fall into two general categories: those that absorb propagated microwave energy (electromagnetic waves capable of propagating in empty space or a vacuum) termed free space absorbers and those that absorb standing waves that exist inside waveguides, coaxial lines and other closed volumes where microwave radiation exists. These absorbers are called load absorbers, cavity damping absorbers and bulk loss absorbers.

Attenuation of microwave energy occurs due to the dielectric loss and/or magnetic loss of a microwave absorber. Dielectric loss is found in the imaginary component of the complex permittivity and acts on the electric (E) field. Magnetic loss is found in the imaginary component of the permeability and acts on the magnetic (H) field. Microwave absorbers using dielectric loss to absorb the electric field portion of an electromagnetic wave use carbon particles in many cases as a loading to create the proper complex permittivity. Microwave absorbers using dielectric loss are electrically conductive in most cases. This property has the potential to cause short circuits in some applications where the absorber is located near RF circuits.

Microwave absorbers employing magnetic loss are filled with magnetic fillers, including special irons and ferrites. Dielectric-loss microwave absorbers are generally thicker physically than the magnetic-loss microwave absorbers due to their smaller real and imaginary parts of the permittivity. Magnetic-loss microwave absorbers are thinner physically due to their higher real parts of both the permittivity and permeability. A favorable property of the magnetic microwave absorbers is that they are insulators at DC with volume resistivities of >108 Ω-cm. This property allows their use inside microwave circuit modules near or in contact with circuits....

Answer 8

wire mesh bonded to the buildings ground grid or copper water pipe... finer the mesh the better, especially if the frequencies are microwave. *sigh*. Why? I guess the classic tin foil on the head would work too.

Answer 9

I think you are talking about a smart meter. I would love this answer.