Many detainees continue to organize their illegal drug trades from inside prison walls. A cell phone is an essential means for the detainee to keep the drug organization running and closely controlled. By contacting visitors before they arrive, prisoners can arrange for a transfer of drugs and drug paraphernalia, allowing them to continue the same illegal habit that placed them in custody. Frequently, the family endures harassment from its incarcerated relative, demanding bail when the family recognizes the relative is better served remaining in custody.

https://www.perfectjammer.com/all-cell-phone-jammers-blockers.html

GPS disruption isn’t limited to jamming, either. There are increasing reports that the Russians have been expanding their ability to spoof the system’s signals, point receivers at the wrong locations. In June 2017, we reported on the U.S. Maritime Administration's report about such incidents in the Black Sea in which ships’ navigation equipment was showing their location miles inland. Other reports of location errors had earlier cropped up in Moscow among players of the popular cell phone game Pokemon Go, which relies on a mobile device’s GPS-enabled location services.

https://www.perfectjammer.com/gps-blockers-jammers.html

Although the phone jammer is so effective. Rabo admitted that there are also concerns about the effectiveness of signal jammers, adding there are no jammers at the Medium Security Compound.Garcia said installing jammers “is a tacit (admission) of the fact that they (officials) cannot even implement that policy (prohibiting the use of cellphones). “There is, I suppose, an existing policy to block all cellphone communications (from inmates). We bought (signal) jammers. In other words, cellphones are illegal. The reason you’re putting in jammers is because even if these are banned, I don’t know how cellphones still find their way inside (the NBP),” Garcia said. Of course, the jammer device only prevents prisoners from using their phones, and it doesn't stop them from smuggling.

https://www.perfectjammer.com/all-gsm-3g-jammers-blockers.html

Data from the test show that the micro-jammer’s signal disrupted commercial wireless signals inside the prison cell, which meant that if cellphones were operating inside the cell, they would have been rendered inoperable. At 20 ft. and 100 ft. outside the cell, however, the micro-jammer signals did not disrupt the commercial wireless signals.The data in the report will be used by BOP and the Department to understand the efficacy of micro-jamming, conduct further evaluation of jamming technology, and develop recommendations for strategic planning.

https://www.perfectjammer.com/wireless-wifi-bluetooth-jammers.html

http://www.airsoft-project.com/petites-annonces/jammer-technology.html

https://perfectjammer.livejournal.com/492.html