Can a signal jammer block all mobile phone signals?

In today's era of highly developed information and ubiquitous mobile phones, we often hear the word "signal jammer", which often appears in specific places such as examination rooms and conference rooms that need to be quiet and free of interference. Many people may take it for granted that as long as the signal jammer is turned on, all mobile phone signals around can disappear without a trace. However, is this really the case? Does the signal jammer really have such a powerful "magic" that it can block all mobile phone signals? Generally speaking, signal jammers cannot completely block all mobile phone signals for the following reasons:

Frequency restrictions

- Mobile phones operate on various frequency bands depending on the communication standard used, such as GSM (900MHz, 1800MHz), CDMA, WCDMA, LTE (4G) and 5G (with multiple frequency ranges, including sub-6GHz and millimeter wave bands). Although the most common signal jammers are designed to cover the main frequency bands used by popular mobile phone networks, there may be some less common or newly allocated frequency bands that are not included in the jammer's interference range. For example, some specialized or experimental mobile services may use frequencies that are not targeted by typical jammers.

Signal Strength and Distance from Base Stations

- The strength of a signal jammer plays a critical role relative to the strength of a phone's signal and its distance from a base station. If a phone is very close to a base station with a strong signal, the signal from the base station may be strong enough to overcome the interference of the jammer, especially if the jammer is relatively low power or far from the phone. In this case, the phone may still be able to maintain a weak or intermittent connection with the base station, allowing limited communication.

Advanced Signal Processing and Anti-Interference Technologies

- Modern phones and communication networks are equipped with advanced signal processing technologies and anti-interference capabilities. These technologies enable phones to adapt to changing signal conditions, filter out interference to a certain extent, and maintain a communication link even in the presence of moderate interference. For example, some phones may use error correction codes, frequency hopping, or other techniques to mitigate the effects of signal interference and continue to send and receive data, albeit with reduced performance.

Environmental Factors

- The physical environment in which the jammer and phone are located can affect their performance. Buildings, walls, and other obstacles can attenuate interfering signals, reducing their effective range and strength. At the same time, these obstacles may also have an impact on the propagation of mobile phone signals, but in some cases, they can provide shielding or reflection, helping mobile phones to receive base station signals more effectively, thereby reducing the impact of jammers.

100W 10 Antenna GPS Frequency Desktop Phone Signal Jammer

Regulatory restrictions

- Signal jammers are subject to strict regulatory restrictions in most countries and regions. Manufacturers must limit the power and frequency range of jammers to prevent them from causing excessive interference to legal communication systems. This means that jammers sold on the market are usually designed with limited functions to comply with legal regulations, and therefore cannot cover all possible mobile phone signals.