L

L
Lead acid : A rechargeable battery type most commonly used in automobiles and marine applications. As some batteries can deliver large amounts of current instantaneously and contain sulphuric acid, these must be handled with caution.

Lid : In amateur radio, used to denote a poor or inept operator; a term originally from landline telegraphy.

LIon, Li-Ion : Lithium-Ion, a small but powerful rechargeable battery often factory-installed in laptop computers and handheld devices. As these cells are highly flammable if overheated, they are normally distributed only as part of pre-fabricated battery packs which internally include the requisite temperature sensors and charging circuits.

Loading coil : An inductor placed in series with an antenna element in order to lower the antenna's resonant frequency. May be used singly or in conjunction with a capacity hat.

LPDA : Log Periodic Dipole Array. A multiband Antenna

LSB : (1) Lower Sideband, used primarily in single sideband operation below 10 MHz

LSB : (2) Least Significant Bit, in transmitted digital data