Key Takeaways
• Basic GPS and GSM tracker signals can be jammed, but professional, insurance-approved trackers are built to detect and resist it.
• Quality trackers raise instant alerts if they are unplugged, tampered with, or if jamming is detected, so a theft is flagged even if the signal drops.
• VHF trackers are the strongest defence, because VHF is a different frequency that the jammers thieves use cannot block.
• Using a signal jammer is illegal in the UK.
• For most drivers an insurance-approved GPS tracker is enough; for the highest-risk vehicles, add VHF.
Can a car tracker be jammed? The honest answer is that a basic GPS signal can be, but a professional, insurance-approved system is a very different proposition. These trackers are engineered to detect interference, raise the alarm the moment something is wrong, and, in the case of VHF systems, keep transmitting on a frequency thieves cannot block. Here is how jamming works at a high level, how modern trackers defeat it, and which type suits you.
Jamming Resistance by Tracker Type
| Tracker type | Jamming resistance | Detects tampering | Best for |
|---|---|---|---|
| Basic GPS tracker | Low | Often none | Casual location only, not theft recovery |
| Insurance-approved GPS/GSM (S5, S7) | High | Yes, with alerts | Most cars, insurance requirements |
| VHF tracker | Very high, VHF cannot be blocked by common jammers | Yes | High-value or previously targeted vehicles |
What Is Signal Jamming?
A signal jammer is a device that floods an area with radio noise to drown out the GPS or mobile signal a tracker relies on, so its location cannot be reported. Thieves sometimes use one to try to move a stolen car undetected. It is worth being clear on the law here: using a signal jammer is illegal in the UK, and enforcement around these devices has been tightening. The point of this article is not how jamming is done, but how a good tracker is designed to beat it.
How Insurance-Approved Trackers Resist Jamming
The strength of an insurance-approved tracker is that it does not just report location, it actively watches for interference and tampering. Protection comes in several layers:
• Tamper and disconnect alerts. If the tracker is unplugged, or the vehicle battery is disconnected, an alert is sent instantly.
• Jamming detection. Quality systems recognise when their signal is being blocked and can raise an alert, and many send a final distress signal before the signal is lost.
• Unauthorised movement alerts. If the car moves without the authorised driver tag present, the control room is notified at once.
• Multi-network SIM. A roaming SIM switches between mobile networks for a stable connection, so a single weak network is not a single point of failure.
• 24/7 control room. Every alert reaches a manned monitoring centre, whose staff verify the situation and coordinate directly with police for recovery.
The result is that even if a thief attempts to interfere with the device, the attempt itself becomes the alarm. Explore insurance approved trackers for systems built this way.
VHF: The Ultimate Anti-Jamming Technology
For the highest level of protection, VHF (Very High Frequency) tracking is the answer. Because VHF is a completely different frequency from the GPS and GSM signals that thieves' jammers target, it is effectively immune to them. Even if the primary signal is blocked, the VHF beacon keeps transmitting.
VHF has another advantage: it can be detected even where GPS cannot reach, such as underground car parks, shipping containers or concrete garages, exactly the places thieves hide stolen cars. Police vehicles and helicopters can home in on the VHF signal, and there are many documented cases of vehicles being recovered this way despite jammers being used. If jamming is your main concern, a VHF tracker is the strongest countermeasure available.
A Note on Relay Attacks
Jamming is often confused with the relay attack, a different technique where thieves capture your key fob's signal to unlock and start the car. This is not jamming, but a tracker with Automatic Driver Recognition (ADR) counters it directly: if the car is started and moved without the authorised driver tag present, a silent alert is raised immediately. See our guide to S5 trackers, which include ADR as standard.
Is It Illegal to Jam a Car Tracker?
Yes. Using a signal jammer is illegal in the UK. Beyond the law, jamming does not achieve what a thief hopes, because a quality tracker treats a blocked or tampered signal as a trigger for an alert, and a VHF system keeps transmitting regardless. In short, jamming is both unlawful and increasingly ineffective against modern security.
Which Tracker Should You Choose?
• For most drivers, an insurance-approved GPS/GSM tracker (S5 or S7) provides strong, jamming-aware protection that satisfies insurers.
• If you own a high-value or frequently targeted vehicle, or you have previously had a signal blocked, add VHF for the ultimate defence.
To find the right system for your vehicle and risk level, browse our insurance approved trackers or VHF trackers, or call our team on 0330 055 2777 for advice.
Frequently Asked Questions
Can a GPS tracker be jammed? A basic GPS or GSM signal can be blocked by a jammer. However, professional, insurance-approved trackers are designed to detect interference and raise an alert, and VHF trackers use a frequency that common jammers cannot block.
Are insurance-approved trackers jam-proof? No tracker is completely jam-proof, but insurance-approved systems are built so that any attempt to jam, unplug or tamper with them triggers an instant alert to a 24/7 control room, so the theft is flagged even if the signal drops.
What is VHF tracking and why can't it be jammed? VHF (Very High Frequency) is a different radio frequency from GPS and GSM. The jammers thieves use target GPS and mobile signals, so they do not block VHF, which keeps transmitting even underground or inside a container.
Is it illegal to jam a car tracker in the UK? Yes. Using a signal jammer is illegal in the UK, and it is largely ineffective against a quality tracker that alerts on interference or uses VHF.
How do I stop my car tracker being jammed? Choose a professional, insurance-approved tracker with tamper and jamming detection, and for the highest protection add VHF. Having it discreetly and professionally installed also makes it harder for a thief to find and interfere with.
