In gerneral, attenuation is the loss of signal over distance. Unfortunately, dB loss is not just dependent on distance. It also depends on cable type and gauge (which can differ over the length of the cable), the number and location other connection points on the cable.
•20bB. and below = Outstanding
•20dB-30dB. = Excellent
•30dB-40dB. = Very Good
•40dB-50dB. = Good
•50dB-60dB. = Poor and may experience connectivity issues
•60dB. and above = Bad and will experience connectivity issues
Line attenuation also affects your speed.
•75 dB+: Out of range for broadband
•60-75 dB: max speed up to 512kbps
•43-60dB: max speed up to 1Mbps
•0-42dB: speed up to 2Mbps+