Thieves can obtain illegal cell phone blocker. Sizes range from small portable devices to large briefcases. They send signals at the GSM frequency. This prevents GSM tracking devices in the vehicle from sending and receiving messages.
Yes, the signals transmitted by these illegal devices form bubbles around the vehicle, very effectively "silently" tracking the device and no one knows what happened. This happened recently in Congress, where a large signal jammer was deployed throughout the US Congress that could effectively block all GSM signals in the House of Representatives.
Yes. He can Tracking equipment has three main requirements for resisting interference. First, the device must be able to detect signal interference. Next, he needs to send an urgent message to someone telling him "I'm trapped". The third and most important thing is that you need to be able to send this urgent message at a different frequency than the blocking frequency. Beware of scammers-the solution will fail if there is no other unobstructed frequency.