Full Band Signal Blocker: An Introduction to its Principles, Features, and Common Issues

Understanding the Functionality and Applications of Full Band Signal Blockers

In today’s world, where mobile phones have become an integral part of our lives, it is essential to ensure their responsible use in certain environments. One such scenario is during important examinations like the college entrance examination (known as “gaokao” in China), where it is necessary to block mobile phone signals to prevent cheating. This article aims to provide a comprehensive understanding of full band signal blockers, including their principles, features, and common issues encountered during their usage.

Principles of Full Band Signal Blockers:

Full band signal blockers are designed to effectively block signals from various communication networks, including CDMA (China Telecom), GSM (China Mobile, China Unicom), SCDMA (China Netcom), DCS (1800MHz), PCS (1900MHz), PHS (China Telecom PHS), 3G, 4G, 5G, WiFi, and Bluetooth. These devices are primarily used in locations such as examination halls, prisons, courtrooms, conference venues, libraries, theaters, churches, gas stations, oil depots, gas stations, and hospitals, where confidentiality, tranquility, and protection against interference are crucial.

Working Principle:

The working principle of a full band signal blocker involves scanning frequencies from the lower end to the higher end within a specific frequency range. This scanning process disrupts the reception of message signals by mobile phones, resulting in the inability to detect normal data transmitted from base stations. As a result, mobile phones display symptoms such as network search, no signal, or no service. This disruption prevents the establishment of a connection between the mobile phone and the base station.

Features of Full Band Signal Blockers:

  1. Exclusive Signal Blocking: Full band signal blockers only block mobile phone signals and do not interfere with the normal functioning of other electronic devices.
  2. Limited Interference: These blockers only affect mobile phones within the designated area, ensuring that phones outside the restricted zone remain unaffected. Moreover, they do not interfere with base stations.
  3. Downlink Frequency Blocking: Full band signal blockers specifically target the downlink frequencies of transmitting base stations, while leaving the uplink frequencies unaffected.
  4. Environmentally Friendly: These devices emit electromagnetic fields well below the national standards, ensuring minimal impact on human health.
  5. User-Friendly Operation: Full band signal blockers are easy to operate, requiring only the connection of power and the activation of the switch for automatic functioning.

Common Issues and Solutions:

  1. Discrepancy in Signal Blocking Range: The effective range of a full band signal blocker may vary from the description provided in the user manual due to factors such as the electromagnetic field strength at the blocking site and the distance from the communication base station. Generally, the optimal range is within 300 meters from the device.
  2. Radiation and Health Concerns: Like any electronic device, full band signal blockers emit radiation. However, the radiation emitted by these blockers is significantly lower than the national standards. Additionally, since they are not used in close proximity to the human body like mobile phones, the potential harm to human health is negligible.


Full band signal blockers play a crucial role in maintaining confidentiality, tranquility, and preventing interference in various sensitive locations. Understanding their principles, features, and common issues is essential for their effective usage. By employing these devices responsibly, we can ensure a secure and disturbance-free environment in places such as examination halls, prisons, courtrooms, and hospitals.