Illegal radio wave devices make it impossible to unlock cars and motorbikes

A series of cars and motorbikes on Vong Street (Hanoi) could not be unlocked with smart keys on June 22, according to experts, due to interference from high-power radio wave control devices, causing loss of connection.

The case of cars and motorbikes suddenly not being able to be unlocked with smartkeys at the Nguyen An Ninh - Vong Street intersection in the past few days is not an unusual phenomenon. Using inspection equipment, authorities discovered that a radio remote control device used to turn on and off the water pump at a household on Vong Street was the source of interference, causing the smartkeys of motorbikes and cars to be disabled.

Explaining this issue, Dr. Truong Trung Kien, a graduate of electronics at the University of Texas (USA), said that radio waves have the characteristic of having a bandwidth with a certain frequency to connect two devices. With electronic devices such as smart keys for motorbikes or cars, the width of the frequency and transmission channel is very narrow. When another device emits with high power at a close distance, if the same frequency, the bandwidth will be interfered with and the connection will be lost.

According to him, not only smart keys, other control devices similar to rolling doors, using "amateur" frequency bands (illegal and free use) controlled by surrounding radio waves can also be interfered with. These devices often emit high power to make it easy to control at long distances, but they occupy a frequency band for many users, causing interference to other devices.

According to Dr. Kien, for a device using standard radio waves, the manufacturer must register with the competent authority, the Ministry of Information and Communications, to be granted an operating frequency and to regulate the maximum transmission and reception power level. Because if the frequency is the same, but the transmission power is within the allowable range, it is unlikely to affect surrounding devices.

Radio Frequency Department staff use testing equipment on Vong Street, afternoon of June 22. Photo: Viet An — Radio Frequency Department staff use testing equipment on Vong Street, afternoon of June 22. Photo: *Viet An*

Dr. Hoang Ngoc Tan, Head of Automotive Engineering, Faculty of Mechatronics and Electronics (Lac Hong University) explained that the interference mechanism is that the device creates a "wall" that prevents communication between the receiver and transmitter of the surrounding radio-controlled device. This communication uses a fixed frequency, mostly in the form of short frequencies. When there is an interference device, the transmitter still operates, but the receiver does not receive the signal.

According to Mr. Tan, smartkey unlocking devices for motorbikes and cars often integrate anti-interference components in the circuit. However, the purpose of magnetic locks is to operate within a short range, so manufacturers often pay little attention. They focus more on security and anti-theft issues for vehicles. If anti-interference is integrated with higher technology, the cost will increase.

Experts all believe that the incident of the remote control pump causing interference in Hanoi is likely due to the homeowner accidentally buying a smuggled device without a certification stamp, which affects other devices. In addition to the interference issue, experts say that using high-power radio wave transmitting devices can affect health because electromagnetic waves can affect the brain and other parts of the body.

To handle when the smartkey loses connection due to signal interference, according to Mr. Ngo Dang Luu, an electrical - electronic expert, Director of Anh Minh Global Company, when realizing that the car cannot be unlocked, the car owner should try to set a warning by pressing the lock button on the remote control or using a physical key. This helps the car owner detect interference and ensure the safety of the car. In addition, when encountering interference, the car owner can move closer to the car and try the unlocking process again. Being closer can help the signal transmitted to the magnetic locking system be stronger and overcome the interference.