The Viking Thunderbolt is a self contained radio frequency power amplifier capable of CW and AM, SSB or DSB linear operation over a continuous frequency range of 3.5 to 30 megacycles. The amplifier employs two Type PL175A pentode tubes in parallel, bridge neutralized, which permits power inputs of 2000 watts P.E.P. linear with suppressed carrier, 800 watts AM linear, and 1000 watts class C continuous wave. Drive requirements are approximately 10 watts from a well regulated exciter for class AB2 linear (SSB and AM) operation and 20 watts for class C (CW) operation. TVI suppression, spurious filtering, rigorous shielding, and parasitic oscillation suppression are included in the amplifier design. The complete Thunderbolt amplifier including high voltage, regulated screen and regulated bias power supplies is contained in a cabinet 21" wide x II 5/8" high x 16 7/8"deep. The total weight is 120 pounds. The Thunderbolt is fully protected by fuses and also by a series screen limiting resistor which limits the screen dissipation to a safe value even in the event of a complete bias failure.