Antenna Cables: What's important?
For the quality of the antenna cable, there are some important factors that should be considered before buying a cable. Here, one should pay attention especially to the following characteristics of the coaxial or antenna cable: Characteristic impedance, attenuation, shielding or insulation of the cable and of course general, and physical length.
The characteristic impedance of a cable provides information about how waves behave in a conductor. It is specified in ohms. Only coaxial cables with a characteristic impedance of 75 ohms are suitable for transmitting TV signals.
The attenuation of an antenna cable is measured in decibels and is also indicated in this way on the cables (dB). Example specifications of the TELASS 100: Attenuation on 100 m (dB/100m): 5.6 dB at 100 MHz, 16.4 dB at 800 MHz and 26.7 dB at 2000 MHz. With these values, one can roughly estimate how good an antenna cable is. However, this is influenced by other environmental factors, such as ambient temperature.
✔ Nevertheless, there is a simple rule of thumb: The lower the signal attenuation, the better!
The screening attenuation of a cable is specified in the same way as the attenuation in decibels (dB). This should be as high a value as possible. For TV signals, antenna cables with a shielding of more than 85 decibels ( >85 dB) are generally sufficient. Antenna cables with a higher shielding value are necessary if there are interfering signals or sources of interference in the vicinity (e.g. electrical devices with a similar frequency to the signal conducted in the cable). For a simplified overview, there are 3 different shielding classes relevant for TV signals: Class A: <85dB, Class A+: <100dB, Class A++ : <110dB
The length of an antenna cable must be sufficient to connect the receiving equipment to the antenna. This is completely different depending on the household and should be measured beforehand.
✔ Since the signal attenuation of an antenna cable increases with increasing length, the cable should be kept as long as necessary and as short as possible.
There are ready-made antenna cables with connectors on both ends. If the connectors are not included or if you want to lay your antenna cable in individual length, there are twist-on connectors. For a cable connection, a coaxial connector (Belling-Lee plug) is required, which has either a male or female pole. For satellite reception, on the other hand, you need an F-connector (F-compression plug), which is screwed either to the antenna itself or to the antenna socket.