Can Trackers Be Jammed? Yes — Here’s Why You Need an Immobiliser

Thieves use cheap jammers to block GPS and GSM signals. LockCar’s immobiliser works regardless of jamming.

GPS jamming · GSM blocking · Physical security · From £79

GPS trackers are valuable recovery tools, but they have a critical vulnerability: they can be jammed. Thieves use cheap, portable jammers that broadcast radio noise on GPS and GSM frequencies, blocking the tracker from transmitting its location. A jammed tracker is invisible — and your car cannot be recovered via tracking. LockCar’s approach prioritises prevention: a relay immobiliser that stops the car being driven in the first place, regardless of whether tracking signals are jammed.

How GPS and GSM jammers work

GPS jammers (also called “GPS blockers”) are small devices that broadcast radio interference on the frequencies used by GPS satellites (L1 band, 1575.42 MHz). When a jammer is active within a few metres of a GPS receiver, the receiver cannot lock onto satellite signals — location data stops updating. More sophisticated jammers also block GSM/4G frequencies (800–2600 MHz), preventing the tracker from sending data via cellular networks. A thief with a £50 jammer can effectively “blind” any GPS tracker within a 5-10 metre radius.

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Using a GPS jammer is illegal in the UK under the Wireless Telegraphy Act 2006. But thieves don’t care about legality. Relying solely on a tracker means your security can be defeated with a cheap, pocket-sized device.

Jammers are cheap and widely available

Despite being illegal, GPS jammers are easily purchased online from overseas sellers for £30–£100. They are small enough to fit in a pocket and are powered by a 12V socket or internal battery. Professional theft rings use them routinely. Police reports show that many stolen vehicles fitted with trackers were not recoverable because jammers were activated within minutes of the theft. The jammer is typically turned on before the thief approaches the vehicle, meaning the tracker never gets a chance to send an alert.

£30-100Cost of a GPS jammer online

5-10mEffective range of a typical jammer

£79From for LockCar i226 immobiliser

LockCar immobiliser range — jamming-proof security

Jamming-proof

LockCar i226 — £79

Wired relay immobiliser

No GPS, no GSM, no jamming vulnerability. Physical relay cut requires authorised tag or app signal to start. The thief cannot drive the car away, jammer or not.

LockCar IC3ST — £139

Standalone app + tag

Relay-based immobiliser with Bluetooth authentication. Bluetooth signals are harder to jam than GPS/GSM, but the physical relay is the real protection — no start even if signals are blocked.

LockCar IS357 — £149

App + tag + immobiliser

Dual-factor authentication with physical relay cut. No reliance on GPS or cellular networks for its core security function.

Why an immobiliser is jamming-proof

A relay immobiliser has no radio signals to jam during normal operation. The LockCar MCU communicates with the authentication device (tag or phone) via encrypted short-range radio (typically 433MHz or 2.4GHz). While this signal can theoretically be jammed, the immobiliser defaults to “locked” — the relay remains open, and the engine will not start. Even if a thief uses a powerful wide-spectrum jammer, the car simply will not start. This is the fundamental advantage of immobiliser-first security: prevention doesn’t require transmission.

Can a thief bypass the immobiliser by cutting and rejoining wires?

Professional installation hides the relay and wires. A thief would need to identify which circuit is cut (starter, fuel pump, or ignition) and install a jumper. This takes significant time and mechanical skill — most thieves will move on.

Should I still get a tracker if thieves can jam it?

Trackers are still useful for recovery when jammers aren’t used. But don’t rely on a tracker alone. The best security is an immobiliser (to prevent theft) plus a tracker (to aid recovery if prevention fails).

Immobiliser — UK wide