The 50-50 grind is the first grind trick that most skaters learn, and is a great basic skateboard trick to learn. The 50-50 grind is where the skater grinds the ledge or rail with both trucks. The nice thing about the 50-50 is that you can learn to do it on a curb, which is a pretty safe and easy place to practice.
dBi is decibels relative to isotropic radiator which means that the radiator (an antenna, usually) sends the signal equally strong in all directions, including above and below. Such a radiator would have 0 dBi.(I have yet to see an antenna like that -- it may exist only in math theory.).Bi is decibels relative to isotropic radiator which means that the radiator (an antenna, usually) sends the signal equally strong in all directions, including above and below. Such a radiator would have 0 dBi. (I have yet to see an antenna like that -- it may exist only in math theory.).
GFCI is an acronym for ground fault circuit interrupter. It is a circuit breaker, or a trip-switch so that should a hair dryer fall into the sink, the circuit will trip, shutting off the electricity to the outlet. These are now code for any outlet within 6 feet of a sink. Some jurisdictions provide other rules on where an outlet can be positioned in relation to a sink.