Jammers found ineffective in Kerala jails; drone surveillance on the anvil

Thiruvananthapuram: The Jail Department is planning to do away with the current system of use of jammers at central jails to block the illicit phone calls made by convicts. The department is seriously considering the option of pressing into service drones for surveillance to find out the mobile use of convicts.

The Jail Department considered doing away with jammers after realising that the convicts are making unlimited number of phone calls every day despite the presence of the jammers to block phone connectivity from 3G SIMs.

At many places, these jammers were destroyed by the convicts. Most of the convicts are using 4G phones, rendering the 3G jammers installed at the jails ineffective. The Jail Department feels that even if it installs jammers for blocking connectivity for 4G SIMS, it will be of no use since the convicts will then easily switch over to using 5G SIMs.

Moreover, when jammers were installed at Poojappura, Viyyur and Kannur central jails, residents staying in the vicinity of jails complained that they were not getting 3G phone connections. It was also reported that the jammers installed at the Tihar Jail in New Delhi did not seem to be effective.

(A jammer is a mobile communications device that transmits on the same frequency range as a cellphone to create strong cell tower interference and block cellphone signals and call transmission.)


According to Jail DGP Sheikh Darvesh Sahib, the aerial survey of the jail compounds using drones are actively being considered to track the phone calls of convicts.

But the main issue is that the phone calls can be tracked using drones only if the convicts come out of their cell to make calls. According to officials, the convicts usually come out of the cells because of lack of phone connectivity inside the cells.


The Jail Department has already taken steps to install linear junction detectors at jails to unearth the phones that were buried inside the ground. This system can track phones buried 15 cm deep inside the ground.

Though two tenders had been called for the work, there were no takers. The question also remains about the efficacy of the system as the convicts usually keep phones in their hands and make calls.


The Jail Department is also planning to implement the 'dominant tower' idea currently being worked out in the Tihar Jail. As per the plan, a tower of each service provider such as the BSNL, Jio and Airtel would be installed at the 400-acre campus of the Tihar Jail to effectively block the phone calls of the convicts.

Dominant Tower restricts the use of mobile phones coming in its range.

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