a time. Models equipped with a UHF antenna can respond to UHF remotes; these remotes use radio frequencies rather than IR signals to control the receivers. UHF signals can reach up to 30 meters, depending on the restrictions of building materials. All UHF-compatible receivers can simultaneously respond to IR signals except for model 4500. For this model, modification directions exist on the Internet to add IR receiving capability, in order for the receiver to respond to programmable universal remotes. Remote #2 of the 3200, 5200, 9200, and the remote for model 6100 are based on "UHF Pro". "UHF Pro" remotes are strictly compatible with the receivers they are provided with and do not function on regular UHF-compatible receivers. Additionally, "UHF Pro" remotes can only communicate with UHF frequencies and cannot control receivers via IR. To prevent interference with other UHF remotes in proximity, clients should change their remote addresses. All secondary remotes for dual tuners may also be converted to remote #1 by flipping the plastic bottom of the remote. This also switches its transmission mode from UHF Pro to regular UHF and IR, similar to how a 5900 remote operates. Satellite dishes Bell Satellite TV currently provides 50 cm (20") dishes to its customers. Canadians living in the territories and certain parts of British Columbia and northern mainland portion of Newfoundland and Labrador require larger dishes between 60 and 120 cm; these are used to compensate for the weaker satellite signal available to these regions. The 50 cm dish supports two LNBs. The size of the dish was increased from 18 to 20 inches in late 2001 to accommodate a second LNB to acquire signal from Nimiq 2 (BEV 82) satellite. At the end of the dish's arm, a Y-adapter is found which holds both LNBs. The BEV 91 LNB is in the centre of the dish while the BEV 82 LNB is offset to the left. Rotating the dish (i.e., modifying the skew angle) changes the position of the 82 LNB while maintaining position for BEV 91. A switchbox, typically an SW21 or SW44, is used to merge both satellite signals into receivers. Smartcards To authorize programming, a portable smartcard is used for older receivers. This includes the 1000, 2700, 2800, 3000, 3100, 3500, 3700, 4000, 4500, 4700, 5100, 5800, 5900 and the 6000. In some cases, Bell Satellite TV has switched back to using standard smartcards for