American analysts first noticed the Russian military portable jammer drones in eastern Ukraine after the invasion of Crimea four years ago, Humphreys said. The jammers “had a pretty significant impact” on UN surveillance drones, which were grounded for days after gathering intelligence from the air. American military officials would not say whether the latest jamming has caused drones to crash, citing operational security.
Cell phone jammers have been around since 1998. The devices can block signals in a room about the size of a movie theater. The jammer sends out a low-power, encoded radio signal or modulated radio wave.Jamming is a synonym for intentional interference, which is the deliberate radiation of electromagnetic signals at GNSS frequencies. Hereby, the aim is to overpower the extremely weak GNSS signals so that they cannot be acquired and tracked anymore by the GNSS receiver. Besides military jammers, which are an integral part of navigation warfare (NAVWAR) strategies, so-called Personal Protection Devices (PPD) are encountered more and more frequently. PPDs are small, light-weight jammers that are easily available via the internet. Their use is of course forbidden in the majority of countries; however, the possession of these devices is not regulated everywhere with the same strictness. Besides intentional interference, unintentional interference also occurs. Some GNSS bands are shared with certain radars, as well as amateur radio. Other sources are Distance Measuring Equipment (DME) used for airplane navigation, TV harmonics, as well as malfunctioning electronic equipment.
BBC reported that June 20-25 is the time for Algeria’s high school graduation exam. During this time, social networks across the country will be shut down for an hour after the exam begins to prevent it from leaking out.
Similar tests occurred in 2010, but Williams said Wednesday’s effort was significant because jamming technology has evolved, as have inmates’ efforts to smuggle in the devices. Such tests, she said, could lead to the broader use of technologies like jamming inside prisons to immobilize inmate phones, which officials across the country have described as their No. 1 security threat.
Russia’s Rossiyskaya Gazeta daily cited military experts as saying that the Rychag-AV jammers added significantly to reducing the effectiveness of the US air strike on Syria’s Ash Sha’irat airbase in April 2017.