There are two main types of heat pumps: geothermal heat pumps and air-source heat pumps. A geothermal heat pump draws the heat from the ground, while the air-source type pulls the heat from the air outside.
RF cables are a type of coaxial cable that is used to send radio frequency signals. RF cables are often used to send video information to a TV set. Identification. RF cables can be identified by the connectors at the end of the cables. RF cable connectors have a single pin that plugs into the RF input on a TV or other device and a threaded piece of metal around the connector that can be used to secure the cable to the RF input port. RF cables are commonly used in cable TV and Internet connections.
Information Useful for Working Out RFI Problems. In the US, a TV channel is a 6 MHz wide chunk of bandspace. The bottom edge of the over-the-air channel 2 is 54 MHz and the upper edge is 60 MHz. Within this 6 MHz space is a video carrier, a color carrier, and an audio carrier. The frequency of the video carrier is 1.25 MHz above the lower edge, so for TV Channel 2 the video is at 55.25 MHz. The color carrier is approx. 3.58 MHz above the video carrier (N.B. not the lower edge), so for TV Channel 2 it is 58.83 MHz.