Belden Essential Cable Facts: High Frequencies
Attenuation (the loss of signal) is an important parameter measuring signal strength. Less attenuation provides a stronger signal which results in a better performing, more robust network.
Investing in a top-notch audio visual system and saving on cabling is a classic example of being penny-wise and pound-foolish. But even when you take your cabling seriously, it is not that easy to pick the right cable. Inferior grade cables can often show a comparable AWG in their basic specification but record very different electrical results!
What cable components are critical?
When it comes to high frequencies, the key component is:
- The conductor: the core of the cable that transfers energy or signals from point to point.
The cross section of a cable conductor plays a crucial role in the cable design. This cross section is represented as an AWG measurement (American Wire Gauge). What makes it tricky is that there is a wide tolerance between the different AWG sizes. Inferior grade cables can often show a comparable AWG in their basic specification but report very different electrical results.
Cable Design 1
Cross section: 0.126 mm2
Attenuation 28.66 dB over 100 MT
Cable Design 2
Cross section: 0.140 mm2
Attenuation 26.71 dB over 100 MT
The higher the size of the cross section, the higher the copper amount. Within the same AWG-size there is a possibility for lower attenuation (signal loss) and higher resistance.
What is the threat of high frequencies?
- The frequency being applied to a cable has a direct impact on the strength of the signal and the decrease in its magnitude as it travels from point to point.
- At high frequencies the rate of electron absorption by the conductor increases, resulting in a loss in transmission of the signal strength ('attenuation').
What is the effect of high frequencies on sub-standard cable?
- Cables unable to withstand high frequencies due to insufficient amounts of conductor material can result in sound and visual distortion and system incompetence.
- High frequencies can have a detrimental impact on the performance of audio, video and Tannoy speaker systems, as less signal makes it to the display from the source.