GRID MODULATION.--See Modulation, Grid.

GRID POTENTIAL.--The negative or positive voltage of the grid of a vacuum tube.

GRID VOLTAGE.--See Grid Potential.

GRINDERS.--The most common form of Static, which see. They make a grinding noise in the headphones.

GROUND.--See Earth Connection.

GROUND, AMATEUR.--A water-pipe ground.

GROUND, WATERPIPE.--A common method of grounding by amateurs is to use the waterpipe, gaspipe or radiator.

GUIDED WAVE TELEPHONY.--See Wired Wireless.

HARD TUBE.--A vacuum tube in which the vacuum is high, that is, exhausted to a high degree.

HELIX.--(1) Any coil of wire. (2) Specifically a transmitter tuning inductance coil.