Coaxial Cable Attenuation
Total coax attenuation over a run, end-of-run signal level.
Example
You enter
- Mode loss
- Loss per 100 ft (dB) 6
- Run length (ft) 100
- Source level (dBmV/dBm, optional) 0
You get
- Total loss db 6
- End level -6
Checked against published worked examples from: Belden / CommScope loss curves (by name).
Details, formula, and sources
ScopeTotal coax attenuation over a run, end-of-run signal level, or the maximum run for a target level (Belden / CommScope loss curves).
Formula or tableloss_dB = loss_per_100ft(type, frequency) * length / 100; end level = source - loss; inverse max run = 100 * (source - target) / loss_per_100ft.
Source and editionCoaxial-cable attenuation from the per-100-ft loss at frequency (loss = per-100-ft * length/100), per the cable manufacturer's published loss curves (Belden / CommScope) and the standard CATV/CCTV/SDI practice, by name; first-principles.
Free accessFirst-principles attenuation. The per-100-ft loss is type- and frequency-specific and user-supplied or a flagged default; the manufacturer's datasheet governs.
What governsEstimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
API field namesmode, loss_per_100ft_db, length_ft, source_level, total_loss_db, end_level
- Per-100-ft loss type- and frequency-specific; RG6 6.3 dB, RG59 7.6 dB, RG11 4.3 dB per 100 ft at 1 GHz default (Belden 1694A / 1505A / 7731A)Belden / CommScope datasheets