Related Products:

EGMA-004, EGMA-005, EGMA-006, EGMA-007, EGMA-008, EGMA-013, EGMA-015, EGMA-016, EGMA-019

Related Documents:

EZDP 2020 and 2038


Technical information


Premium Monitoring System, Signal Cables, Cable Length


This article describes the process of adjusting of signal quality for different cable lengths with a chart showing dB loss at various frequencies and distances.

Signal Quality—Signal Dampening or Attenuation

The most important information that monitoring can supply is confirmation of the immediate status of the generator grounding. More advanced information includes waveform-level views of what is happening on the shaft and in the ground current, even at higher-frequency events. The signal quality that you experience is related in large part to cable length and site-specific interference. Model 88777 wire has a linear attenuation rate of 0.09 dB per foot when carrying a 10 MHz signal. The following levels of dampening are associated with each cable length:

  • 30 ft (9 m): -2.7 dB (30 x .09)

  • 50 ft (15 m): -4.5 dB (50 x .09)

  • 75 ft (23 m): -6.75 dB (75 x .09)

Cutsforth considers attenuation exceeding 3 dB to be unacceptable.

The Belden wire spec sheet provides the following data on dB loss per ft @ the frequency stated:

  • 0.1 MHz - 0.0040

  • 0.5 MHz - 0.0190

  • 1.0 MHz - 0.0300

  • 2.5 MHz - 0.0457

  • 5.0 MHz - 0.0700

  • 10.0 MHz - 0.0900


Source: Belden data for Model 88777 at:

These examples are based on distance attenuation of the cable only. In these examples, it is revealed that up to 500,000 samples per second will display reasonably relevant information at distances beyond 40 ft (12 m). However, a 10 MHz signal at 70 ft (21 m) will see a 50% to 60% dampening, not accounting for other factors. So at this distance a 10 MHz element in the waveform may not be discernible from noise.

Do you need more help?

Submit your questions or requests using the Support Ticket Submission form.

Was this article helpful?
0 out of 0 found this helpful