Cable Loss Budget

The Fiber-optic Cable dB Loss Budget calculator computes the transmission loss budget (allowance) in dB over a distance of fiber optic cable based on the length of the cable (L), type of cable (FT), number of connectors (C), the dB loss per connector (CL), the number of splices (S), and the dB loss per connector (CL). 

INSTRUCTIONS:  Choose your preferred units and enter the following:

• (C) This is the number of mated connector pairs.
• (CL) This is the dB loss per mated connector pair (0.75 dB default).
• (S) This is the number of splices.
• (SL) This is the dB loss per splice (0.3 dB default).
• (FT) Choose a type of fiber-optic cable (see list below).
• (L) This is the total length of the cable.

dB Loss Budget: The calculator returns the transmission Loss Budget in dB.  The Loss Budget is a reasonable expected transmission loss (attenuation) based on normal factors.  If the loss is greater than the budget, one must assume that loss in the system is due to abnormal circumstances that need to be corrected.

The Math / Science

To test a fiber optic cable plant, you need to perform a loss test.   The loss across a fiber-optic line is a function of the loss in the fiber optic cable itself and the loss introduced by connectors and splices. 

The typical mated connector pair loses 0.75 dB for each connector.    A splice typically introduces 0.3 dB loss. 

The loss for different types of fiber cable is as follows:

• 1550 nm singlemode fiber loses 0.4 dB every kilometer.
• 1310 nm singlemode fiber loses 0.5 dB every kilometer.
• 1300 nm multimode fiber loses 1.0 dB every kilometer.
• 850 nm multimode fiber loses 3.0 dB every kilometer.

If the transmission loss rate is different than the options above, used the dB Loss Calculator.  The dB Loss Calculator lets you manually enter the dB loss per kilometer.

Time Dependent Calculators

• Time required to process an amount of data at a specific data processing rate
• Amount of time required to transfer an amount of data over a different types of networks
• Number of items (unit-less) produced over time
• Length or distance processed (produce or consume) over time
• Area processed (produced, covered or consumed) over time
• Volume processed (produced or consumed) over time
• Weight or mass processed (produced or consumed) over time
• Speedup Factor (aka Amdahl's Law)
• Compute Data Storage Needed
• Network Propagation Delay

Telecommunications Calculators

• Propagation Delay Computes the delay between two routers based on their positions and a transfer rate.
• Nodal Delay: Computes the nodal delay based on the queuing, processing, transmission and propagation delay.
• End to End Delay Computes the end to end delay based on the number of nodes and the processing, transmission, and propagation delay.
• RF Velocity of  Propagation:  Computes the RF velocity based on the medium permittivity
• Transmission Delay: Computes the delay based on length of packet and transmission rate.
• Data Transfer Time Calculator Computes the time to transfer an amount of data based on the data transfer rate.
• Simplified Propagation Delay: Computes the delay between two router based on the distance and the transfer rate.
• Surge Impedance Loading: Computes the power loading of a transmission line.
• Amdahl's Law: Computes the total system speedup time based on the improvement of one portion.
• Signal-to-Noise Ratio (SNR) calculator: Computes a relative measure of the strength of the received signal (i.e., the information being transmitted) compared to the noise.
• Compute Data Storage Needed: Computes the approximate amount of data storage needed based on a period of time and a data rate.
• Network Propagation Delay  Computes the propagation delay based on the positions of two routers and the propagation speed.
• Shannon-Hartley Theorem: Computes the theoretical upper limit data rate of a channel based on the bandwidth, receiver strength and channel noise.
• Cable dB Loss Budget Computes db loss based on length of fiber run and number of connectors.
• Voltage Resolution (Analog to Digital) Computes the Voltage Resolution of a measured analog signal over the nominal range [VL , VH] with a specified number of conversion bits.
• Effective Isotropically Radiated Power (EIRP): Converts an EIRP measured in mw (milliwatt) to the unitless ratio of dBm (ratio of decibel to 1 milli-unit).
• Length of Cable with Sag: Computes the length of cable between pole accounting for the sag.

Cable and Conduit Installation Calculators

• Electrical Metallic Tubing (EMT) Calculator:  This provides the installation time and length estimates and the weight of EMT conduits.
• Galvanized Rigid Conduit (GRC) Calculator: This provides the installation time and length estimates and the weight of GRC conduits.
• PVC Schedule 40 Conduit Calculator: This provides the installation time, length and weight of PVC schedule 40 conduits.
• Metal Clad (MC) Cable Calculator: This provides the installation time, length and weight of metal clad (MC) cable.
• Fiber Optic Cable Loss Budget Calculator:  Computes the acceptable dB loss in signal over a fiber-optic network based on the material type, number of connectors and splices and the overall length of the run.
• Voltage Drop Calculator:  Computes the voltage drop over a length of cable and provides the needed gauge to keep voltage drop above a threshold.
• Telecommunications Calculator: This provide network and communications functions.
• Rolling Offset: Computes the run and travel distance in a rolling offset