  Devices as Large Ring Laser Gyroscopes (RLG) for fundamental physics and
geophysics investigation are currently run by means of RF power supply systems.
This is not the standard method to supply a gas laser, that typically is
powered with a DC system. In literature RF power supply lasers have been
studied several years ago, and to correctly understand the behaviour of devices
as RLG a more detailed study has been pursued. Detailed study of the radial
distribution of the optical gain of an He-Ne discharge cell in function of gas
pressure and RF power supply will be illustrated, discussed and compared with
existing literature. The presented analysis demonstrates that it is possible to
optimize the RLG operation with a proper choice of gas pressure and power level
of the RF power supply. Accordingly we have been able to establish transversal
and longitudinal single-mode operation our prototype GP2.
