The designation Solid State Power
(SSPA) only indicates that it is a transistor amplifier.
Thetype of power amplifier involved, whether an RF power ampl
ifieror an AF power amplifier, is not clear from this designation,
nor is thefrequency range, gain factor
or other characteristic values. Normally, RF transistor amplifiers, High Power Amplifiers (HPA) or Travelling Wave Tube Amplifiers (TWTA) used in satellite transmission are constructed as solid state power amplifiers.