Systems, methods and devices for a coaxial cable transmission system. A power supply receives a primary power signal from a power source. The power supply generates a switched direct current power signal from the primary power signal. A power gateway receives the switched direct current power signal over a coaxial cable from the power supply. The power gateway generates a secondary power signal from the switched direct current power signal. A load device receives the secondary power signal from the power gateway. In some implementations, the power supply generates the switched direct current power signal at a positive direct current voltage level for a first part of a time period and at a negative direct current voltage level for a second part of the time period.