The typical shortwave transceiver offers a transmission power of 100 or 200W. This is sufficient in many cases, but in some situations, more power may be needed for a reliable connection. This is especially true during periods of minimum solar activity, but also when participating in a contest or when achieving ambitious goals as a DXer.
Final amplifiers for short wave are available as tube amplifiers or with semiconductors. Tube amplifiers usually offer better efficiency, higher output power is easier to achieve. On the other hand, the units are usually larger and heavier and need to be better cooled. Semiconductor power amplifiers are perfect for the lower to medium power range, these amplifiers are generally more compact and lighter.
Tube amplifiers are available with manual or automatic tuning of the output circuit. Automatic tuning is comfortable but also very complex, that is why these PAs are more expensive. The tuning of the output also allows compensation of not so perfect SWR of the antenna. With semiconductor power amplifiers the output circuit is designed differently and requires antennas with very good SWR (or an external tuner for high power).
The typical power of a shortwave power amplifier is thus 500 to 1200W, but there are also models with up to 4000W output power. The limits are set by the respective law in the country where the plant is operated. WiMo offers a wide range of performance classes and models, from the most famous manufacturers worldwide.