Some samples of signal jammers. Photo by VnExpress/Kieu Tien
According to Duy, signal jammers interfere or block the signal from the wireless microphone to the loudspeaker or interrupt Wi-Fi connections so that the singer will have trouble singing or be unable to pair their devices.
Prices range from several tens of thousands to multiple millions of dong, although how well they work for this particular problem is debatable.
“The jammer will interfere with this frequency range, causing the connection between the microphone and the speaker to be affected,” explained Nguyen Dai, a radio equipment repair technician in Ho Chi Minh City. “It also causes Wi-Fi radio waves to flicker, causing unstable connections in devices used for singing such as smartphones, tablets…this inhibits users.”
However, he said that these devices are often expensive, arguing that the cheap models currently rampant in the market and e-commerce sites are unlikely to have the ability to actually disrupt the radio waves. Therefore, users should research carefully before buying.
In fact, Nhu Quynh tried to buy a signal jammer for VND500,000 online. However, the device barely works and so she said it was “not worth it.”
On Duy’s Facebook group, many people have complained that they bought cheap devices that didn’t work, or only worked within extremely close range.
Bui Quoc Tuan of the Ho Chi Minh City Bar Association said that only agencies under the Ministry of National Defense and the Ministry of Public Security can trade in mobile communication jammers and disruptors.
Meanwhile, the law stipulates that signal jammer buyers first need to get approval from the ministry.
According to the Tuan, buying a signal jammer to interfere someone else’s wireless karaoke machine is against the law.
Depending on the level and behavior, violators can be fined between VND2-50 million and their equipment will be confiscated.