high frequency cable
A high frequency cable is, as the name suggests, a cable that can transmit high and highest frequencies. The classic high-frequency cable is the coaxial cable, which, depending on the design, can transmit frequencies of over 10 gigahertz, such as the RG-214 and RG-223 RF cables.
The structure of coaxial RF cables
Coaxial RF cables consist of an inner conductor, which can be a copper wire or a multicore stranded wire, the dielectric, one or two shields, which can be foil or braided shields, and the outer jacket. To reduce the skin effect and thus the attenuation, the inner conductor and the braided shield are silver-plated.
RF cables differ in frequency response, attenuation, and thickness, and thus in transmittable power, to name a few important criteria. The outer diameter is about 2.5 mm for the thin cables such as RG-174, about 5 mm for the somewhat thicker ones such as RG-58 or H-155, and about 10 mm and 15 mm for the thick cables such as RG-214.
Characteristic values of RF cables
High frequency cables usually have an impedance of 50 Ohm. This value is a compromise resulting from the cable attenuation. Most coaxial cables have the lowest impedance between 50 ohms and 100 ohms. In addition, the maximum power can be transmitted at an impedance of 30 ohms and the maximum voltage at an impedance of about 70 ohms.
High-frequency cables are used in high-frequency installations, in broadcasting and broadband cable networks, in antenna systems and satellite receiving equipment, and also dominated the cabling of local area networks and broadband networks in the 1970s and 1980s. They are standardized to the American MIL standard, MIL-C-17, to IEC-61196 and to the European standardEN 50117.
RF cables are fitted with RF connectors at the cable ends so that they can be connected to equipment, installations or to other RF cables.
With the development of broadband twisted pair cables, which can transmit frequencies up to 600 MHz in class 7, and the standardization of structured cabling, coaxial cables disappeared from local networks.