The Difference Between External and Internal Antennas in Signal Jammers

Signal Jammers are products used for communication regulation, aimed at ensuring seriousness and tranquility in places such as examination halls, prisons, and detention centers, to guarantee fair and just exams. These devices can be distinguished by their external and internal antennas. External antennas are typically used for high-power machines, while internal antennas are mostly designed for low-power machines. This article will explore the differences between these two types of antennas and their respective applications.

External Antennas:

External antennas in Signal Jammers are located outside the device and extend outward. Due to their external nature and extension, they occupy more space compared to internal antennas. However, this design also provides external antennas with a more stable shielding effect. External antennas are commonly used for high-power machines, as they require a larger coverage area. Their shielding effect is more reliable due to their extended reach.

Internal Antennas:

Internal antennas, as the name suggests, are located inside the Signal Jammer. They are primarily designed for low-power machines. Although they occupy less space compared to external antennas, their shielding effect may not be as stable. Internal antennas are suitable for indoor use, such as in examination halls, conference rooms, and offices, where smaller coverage areas are required.

Choosing the Right Signal Jammer:

When purchasing a Signal Jammer, it is crucial to consider the intended usage location. For indoor use, such as in examination halls, conference rooms, and offices, a low-power model is sufficient. However, for outdoor open areas, a high-power Signal Jammer is necessary to achieve effective shielding over a larger distance. High-power Signal Jammers are typically designed in a portable suitcase-like form, making them bulkier compared to the smaller desktop models used for low-power machines.

Coverage Range:

In general, examination halls tend to use low-power Signal Jammers, with one device installed per classroom, covering an area of approximately 200 square meters. On the other hand, high-power Signal Jammers can achieve a shielding distance of 300-400 meters (actual range may vary depending on local signal strength).


In summary, Signal Jammers with external antennas are suitable for high-power machines, providing a more stable shielding effect due to their extended reach. On the other hand, Signal Jammers with internal antennas are designed for low-power machines, offering a smaller form factor and portability. When selecting a Signal Jammer, it is essential to consider the intended usage location and the required coverage range to ensure optimal performance.