The average computer stand can be raised from 3 cm to 2 cm, and some can be raised to 25 cm. In fact, this height is not suitable for computer operation. In general, the height of raising our hands when our arms are on the table is generally 15 cm, which is between 1 cm and 15 cm, which is most suitable for normal people. In order to reduce the impact on the main building, the height of the antenna is generally increased by using the heightening frame, antenna mast or light antenna tower. The heightening frame has the advantages of light weight, low cost and simple installation.