The FL-2100B Linear Amplifier is designed to match the FT-101B/277B transceivers in appearance and drive requirements to run high power input covering the ham bands 80 through 10 meters. The FL-2100B uses a pair of 572B/T160 transmitting triodes in a class B grounded grid circuit configuration. The tubes are forced-air cooled by two very quiet high speed internal fans. Automatic Level Control circuit controls the exciter gain to allow the highest average power without distortion caused by peak clipping. Changeover circuit biases the tubes to cut-off, eliminating unwanted heat and diode noise generation when receiving. An internal changeover relay feeds the antenna to the exciter for barefoot operation when the FL-2100B is turned off or is on standby condition. A built-in SWR bridge measures SWR on by barefoot and linear operations. The built-in solid state power supply requires no warm-up period and provides excellent voltage regulation.