Signal jammers installed in police vehicles are not working as expected, since the police have come under several remote-controlled bomb attacks recently.
People familiar with the matter told The Express Tribune that the devices had been installed in all vehicles used by law enforcement agencies to prevent remote-controlled blasts by jamming frequencies used by attackers.
However, police came under attack by such a device in the suburban village of Sheikhan earlier in July, leaving the usefulness of the devices questionable.
A police official requesting anonymity said that signal jammers that were provided to ministers and MPAs were useful, but the units provided to the police mobiles were not. “Why were these tiny machines installed in our vehicles without being properly tested in the first place?” he asked.
An expert at the telecommunications department of the police, who requested not to be named, said there were two kinds of jammers that worked on different frequencies.
The first are called radio frequency (RF) jammers, used to interrupt the frequencies mainly in remote-controlled bombs, TV sets, cars and other devices using these wavelengths. The second type of device is called GSM jammers which block mobile phone signals.
“Unfortunately, installing just one type of the jammers is not enough,” he said. “In a majority of cases, attackers use the RF frequency which is blocked, but sometimes where mobile phone signals are used, the devices are completely ineffective.”
Police vehicles mostly have RF jammers installed in their vehicles. The GSM jammers are available in the market for about Rs35,000.
“A lot of police officers have bought the GSM devices themselves and installed them as the government does not provide them,” he added.
He also said that jammers were easily available in Karachi for a few thousand rupees. “Several mosques are even equipped with it,” he said. Ultra-portable devices are also available that can be carried in pockets that jam all mobile phones within a radius of a few metres.
No high-ranking police official was available for comment on the matter.
DSP Khurshid, whose vehicle was attacked in the Sheikhan village, said that there was a jammer installed in his vehicle. “But they only work when the engine is running, and I had switched off my engine,” he said.
Published in The Express Tribune, August 23rd, 2012.