In my previous article "Interference distance and signal transmission distance of the interfering transmitter", I mentioned that obstacles in the signal transmission path reduce the distance of signal transmission. We take the wall as an example to specifically analyze the influence of different obstacle materials on the penetration ability of the signal emitted by the jammer. The largest number of customers buy jammers for cell phones. In the following, I will once again analyze cell phone jammers as an example.
A Cell phone jammer is a device that interferes with cell phone signals by emitting high-frequency signals. When the transmitted signal hits a wall, it will be attenuated differently due to the different wall materials, which will affect the interference distance of the jammer. If you have read my previous article, you will know that factors such as wall material, signal frequency, ambient signal strength and output power of the signal emitted by the jammer together determine the jamming effect of the jamming signal emitted by the device in the area behind the wall. We start with the wall material and signal characteristics to examine the effects of different wall materials on the penetration ability of signals emitted by cell phone jammers.
1. types of wall materials and their signal attenuation
Different types of wall materials have different blocking and absorption effects on cell phone signals. According to the characteristics of wall materials, their effect on the penetrability of signals transmitted by cell phone jammers is mainly reflected in the degree of signal reflection, absorption and refraction. In the following, we divide different materials into three categories for specific analysis:
(1) Materials with low attenuation
Plasterboard, drywall (-2 dB)
Lightweight steel keel plasterboard and drywall are materials with low signal attenuation. These materials have a low density and attenuate signals emitted by cell phone jammers less. Jammer signals can easily penetrate these walls and interfere with cell phone signals in the area behind the wall.
Wood (-5 to -12 dB)
Wood has a limited signal absorption capacity, especially thinner wooden doors and decorative walls have a lower attenuation. Although jamming signals suffer some loss when penetrating these materials, they can still maintain a strong penetration capability. Most jammers can transmit signals that penetrate thinner wood. However, if the signal is weakened and the signal strength is less than the signal to be jammed, the jamming effect may not be achieved.
Transparent glass (-4 dB)
Did you know that ordinary glass has little effect on the signal transmission of a cell phone jammer? Ordinary glass has little effect on the signal of cell phone signal jammers. Jamming signals can be transmitted directly through glass windows, creating the illusion that the signal jamming capability of the area behind the wall is enhanced.
(2) Materials with medium attenuation
Plywood (-4 to -6 dB)
Plywood is a material with medium attenuation. Its blocking effect on interference signals is somewhat stronger than that of plasterboard. Especially when plywood is damp, the signal attenuation increases considerably, even up to -20 dB. You will notice that the material analyzed below has a considerable influence on the attenuation of signal transmission!
Plaster (-8 to -16 dB)
Gypsum is a common building material with high density. It has a stronger ability to absorb interference signals, which significantly weakens the signal's ability to penetrate. In fact, we have conducted many tests. The reduction of the signal emitted from the jammer by this material has made the interference effect very low. If you buy a high-power jammer, the interference signal it emits may still be effective after penetrating the plaster. With low-power jammers, our tests show that the signal cannot maintain the interference effect after penetrating the plaster.
Brick walls and stones (-8 to -28 dB)
Due to their high density and thickness, brick walls and stones have a very obvious blocking effect on interference signals. The interference signal is greatly weakened when it passes through these materials, resulting in a significant reduction in the interference effect in the area behind the wall. I have analyzed plaster above. Brick walls and stones weaken the signal more than plaster. You should understand what I mean.
(3) Materials with high attenuation
Concrete and cement (-10 to -20 dB)
Concrete and cement are the main materials used in modern buildings. They are dense and thick and signals have difficulty penetrating them. For cell phone signal jammers, this type of wall will significantly weaken the signal's ability to penetrate. Are the walls of your house made of concrete and cement?
Tinted glass and low-E glass (-24 to -40 dB)
Tinted glass and low-E glass contain metal additives that reflect and absorb more signals, and interference signals can hardly penetrate this type of glass. Please note! The signal-attenuating effect of tinted glass and Low-E glass differs from that of normal glass!
Metal (-32 to -50 dB)
Metal walls are the strongest signal jamming materials and block the propagation of jamming signals almost completely. The jammer's signal is almost undetectable behind a metal wall. Have you noticed that some metals are very effective signal isolation materials?
For high attenuation materials, we have tested that even the signals emitted by high power jammers have difficulty penetrating these high attenuation materials, not to mention maintaining the jamming effect. Normally, we say that the jammer's jamming effect cannot penetrate walls because we assume that walls are made of concrete and cement. Do you understand?
2. the influence of the interference signal frequency on the penetration capability
The frequency of the interfering signal has a significant influence on its ability to penetrate wall materials. Have you considered this factor? Let me analyze this in detail: Low-frequency signals have longer wavelengths and stronger diffraction power, so their ability to penetrate walls is relatively strong; while high-frequency signals have shorter wavelengths and are easily absorbed or reflected by walls, so their penetration ability is weaker.
Low-frequency signals (ten to one hundred MHz)
The signal frequency is similar to that of a radio transmitter and has a strong penetration capability. It is suitable for penetrating materials with low attenuation, such as plasterboard and wood. However, the signal is still severely impaired in materials with high attenuation, such as brick walls and concrete.
High-frequency signals (hundreds of megahertz to gigahertz)
High-frequency signals have a weak diffraction power and are easily absorbed or reflected by walls. In front of high-density materials such as brick walls and concrete, it is significantly weakened or even completely blocked. If you have purchased a jammer, you know that the signals that the jammer interferes with are basically "high frequency signals (hundreds of megahertz to gigahertz)". The signals emitted by the jammer therefore have difficulty penetrating high-density materials such as brick walls and concrete. It's the same thing I analyzed above.
3. the influence of the jammer transmission power on the penetration capability
The transmission power of a jammer directly determines the energy strength of its signal. The higher the transmission power, the better the signal can penetrate walls. I must tell you that even at higher power levels, the signal is considerably weakened or even completely lost if it encounters materials with high attenuation such as brick walls, concrete or metal.
4. influence of open spaces on signal penetration
Interfering signals can propagate through open spaces such as doors and windows, bypass the signal blocking by walls and reach the area behind the walls. In this case, it can easily be misinterpreted as a "strong penetration capability" of the jammer. In reality, I can tell you that the signal does not penetrate the wall, but travels through the open space to reach its destination.
If you read my analysis above carefully, you will know that the frequency and transmission power of the interfering signal also have an important influence on the penetration capability. Jammers transmitting at lower frequencies and higher powers can penetrate walls more effectively in some cases, but are still significantly limited with highly attenuating materials. Are you interested in my analysis of the signal attenuation of different materials? What other findings are you interested in? You can tell me!
