Common Problems :

*When Safety signal shielding device is working,Why do some mobile phone signals instructions still have instructions?
This is just an illusion. In fact, at this time your mobile phone has been unable to communicate. When you press the draw button, you will find, no indicator on the signal indicator.

*Is there a difference in use range when Mobile phone security signal blockers in the indoor and outdoor?
Yes . there is. Mobile phone effective range of safe signal blockers (30 to 40 meters) generally refers to the indoor. In outdoor open terrain, the effective shielding distance can up to a few hundred meters. It should be pointed out that both indoors and outdoors, the effective distance of the block and the environmental conditions at that time have a certain relationship, such as from the base station near and far, placed, etc.

*The equipment Power and shield the distance (range, area) the uncertainty of discuss help the shielding effect of several parameters:
*The output Power

Blockers output Power
The performance of the antenna radiation (antenna gain, directivity, etc.)
Shielding way of working ,Phones are now digital signal, digital signal anti-interference ability is very strong, analog signal technology is commonly used in digital signal interference effect is poorer, so we must use digital signal interference digital signal, the same Power of digital interference signals and of interference analog signals effect in mobile phones, Using digital jamming signal technology shielding device have lower Power and higher efficiency than the analog signal interference technology blockers.

*It is not the same as the indoor and outdoor. Indoor mobile signal attenuation, reflection and interference signal synthesis, analysis is very complicated

*Before shielding, the local space of the signal strength and quality for shielding effect is very big, is different also, the effect of different mobile phones .In general weak signals ability of mobile phone anti-interference effect is not always good.

*The direction of the base station and the direction of the mobile phone shielding area also affect the shielding effect.

*Shielding distance and the radio signal transmission distance feature, Now in a radio signal in free space transmission attenuation shielded from the simple discussion, According to the theory of transmission formula, every double waves transmission distance, attenuation of signal intensity 6 db (a decrease in signal Power four times). We are in a GSM mobile phone immobilizer 900 MHZ. For example, if a cell phone signal strength as the blocked area needs - 50 DBM, shielding effective shielding distance of 10 meters, cell phone signal strength change will directly affect the shielding distance, see the table as flow: