Blonder tongue AMM-806, Reference Manual, Page: 182 / 285

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This equation calculates the percentage of change in cable
attenuation (loss) caused by a temperature change:
% change in cable loss = 1.1% per 10° F
This equation calculates the change in cable loss in a span of cable,
expressed in dB.
change in cable loss (in dB) =
standard loss x % change in cable loss
Cable Loss and Temperature
Example: If the standard loss is 22 dB* when the temperature is
70°F and the temperature drops to -40°F, what is the change in
attenuation for that cable span?
1. Determine the number of degrees of temperature change.
T = T2 - T1 = (-40°F) - 70°F = (-110° F)
2. Find the percent change in cable loss.
% change = 1% per 10°F x (-110°F)
= (1%/10°F) x (-110°F)
= - 11%
3. Find the dB change in the span’s loss.
Change in cable loss (in dB) = -11% x 22 dB
= -2.42 dB
So, if the span’s loss was 22 dB at 70°F it becomes
22 dB + (-2.42 dB) = 19.58 dB at -40°F.
Changes in cable loss accumulate over multiple cable spans
and can cause performance degradation if not controlled by
AGC/ASC units.