Cable Utilities
Multi segment coaxial cable loss, VSWR, and power efficiency analysis. Build a cable assembly from RG 58, RG 8, RG 213, LMR 400, Heliax, and other common coax types and see matched loss, mismatch loss, connector loss, signal delay, and total efficiency.
Coaxial cable loss is the unsung killer of RF system performance. The transmitter is often blamed when sectors underperform, when fade margin disappears in rain events, or when receive sensitivity quietly degrades on a working network. The actual culprit is more often the feeder run. A 30 metre LMR 400 jumper at 5.8 GHz drops over 7 dB by itself. A 30 metre RG 58 at the same frequency drops more than 30 dB and is essentially useless. Connector losses, mismatch loss from a poorly matched antenna, and ageing cable that has absorbed moisture all stack on top. By the time the radiated power reaches the antenna, the budget the design assumed is gone.
The noIM₃ Cable Loss Calculator gives a precise multi segment analysis of a real world coaxial cable assembly. Build the run from segments with their own cable type, length, frequency, and connectors, and the calculator aggregates matched line attenuation, mismatch loss from load VSWR, connector insertion loss, and total assembly loss. Output covers loss in dB and watts, power in versus power out, total efficiency as a percentage, and a visual loss classification (low, medium, high) for fast assessment. A built in cable database covers the common types (RG 58, RG 8, RG 213, LMR 400, LMR 600, Heliax LDF series, Heliax FSJ series) with frequency dependent attenuation derived from manufacturer coefficients.
Beyond loss, the calculator returns the propagation and electrical length parameters that matter for phased arrays, timing critical applications, and impedance matching work. Signal delay in nanoseconds. Wavelength at the operating frequency. Velocity factor of the cable. Propagation velocity. Electrical length in wavelengths. Combined with VSWR analysis (return loss, reflection coefficient, input VSWR, mismatch induced additional loss), the workspace covers every transmission line metric an RF engineer would otherwise pull from three different references and a calculator app.
Construct a real world cable run from multiple segments, each with its own cable type, length, frequency, and connector pair. Suitable for jumper plus feeder plus jumper trunk arrangements typical of cellular and broadcast tower top installations. The calculator aggregates loss across the assembly and reports per segment power output and attenuation.
Separates matched line attenuation (the loss the cable would have feeding a perfect 50 ohm load) from mismatch induced loss (the additional loss caused by a non matched load). Returns return loss, reflection coefficient, input VSWR, and the additional dB cost of the mismatch so antenna VSWR is not silently absorbed into the cable loss number.
Per segment connector insertion loss with sensible defaults for N type, BNC, TNC, SMA, 4.3 to 10, and 7 to 16 DIN connector pairs. Total assembly loss includes the connector contribution explicitly, so the impact of a four connector trunk is visible against the underlying cable loss.
Displays power in, power out, total loss in dB and watts, and overall efficiency as a percentage. A visual loss classification (low, medium, high) supports rapid assessment, and the per segment breakdown identifies which segment is consuming the most power so remediation effort is targeted.
Cable attenuation varies with frequency, typically as the sum of a square root term (skin effect) and a linear term (dielectric loss). The calculator uses manufacturer derived K1 and K2 coefficients per cable type, returning realistic loss at the operating frequency rather than a single nominal value taken from one band.
Returns signal delay in nanoseconds, wavelength at the operating frequency, velocity factor of the cable, propagation velocity, and electrical length in wavelengths. Useful for phased array work where cable length differences translate to phase differences, timing critical applications, and impedance matching where electrical length sets the transformation behaviour.
Built in database of common coaxial cables. RG 58, RG 8, RG 213, LMR 240, LMR 400, LMR 600, Heliax LDF series, Heliax FSJ series, and others. Each entry exposes dielectric constant, attenuation coefficients K1 and K2, maximum frequency, CW power rating, and velocity factor so cable selection can be informed by power handling and loss constraints rather than vendor marketing.
Checks the input power against the CW power rating of the cable type at the operating frequency. Useful for high power transmitter installations, broadcast feeder runs, and any scenario where exceeding the cable rating risks dielectric failure or jacket damage.
Runs entirely in your browser. No cable type, frequency, or installation data is submitted to a server. Useful for commercially confidential infrastructure work and environments where information security policy prohibits sending engineering data to third party services.
Reach for the Cable Loss Calculator in any of the following situations.
RG 58, RG 8, RG 213, LMR 240, LMR 400, LMR 600, Heliax LDF series (LDF4, LDF4 50A, LDF5, LDF6, LDF7), Heliax FSJ series, and other common coaxial cables. Each entry exposes dielectric constant, attenuation coefficients K1 and K2, maximum frequency, CW power rating, and velocity factor. Manual entry is supported for cable types not in the database.
Matched loss is the attenuation the cable produces feeding a perfectly matched 50 ohm load. It is the inherent property of the cable and depends on conductor and dielectric losses at the operating frequency. VSWR (mismatch) loss is the additional loss caused by a non matched load reflecting power back into the cable, which then suffers further loss travelling back to the source. The two are reported separately so antenna VSWR is not silently absorbed into the cable loss number, which is a common source of underperformance on working networks.
K1 and K2 are derived from manufacturer published cable data. Cable attenuation typically follows the form attenuation per 100 feet or 100 metres equals K1 times square root of frequency in MHz plus K2 times frequency in MHz. K1 captures conductor (skin effect) losses. K2 captures dielectric losses. Together they reproduce the manufacturer published attenuation curves accurately across the cable operating range.
Signal delay is the time for a signal to travel from one end of the cable to the other, equal to physical length divided by propagation velocity. Critical for phased array systems where cable length differences become phase differences, for timing distribution where end to end skew matters, for distributed antenna systems where cell handoff timing depends on it, and for any time critical synchronisation work. Output is in nanoseconds for direct use.
Electrical length in wavelengths drives the impedance transformation behaviour of a transmission line. A quarter wavelength of mismatched cable transforms impedance in a known way (the quarter wave transformer), and any non integer wavelength shifts the apparent impedance seen at one end. Useful for matching network design, antenna feed point analysis, and stub work.
Yes. A real world cable assembly often has a short jumper at each end plus a long feeder in the middle, with different cable types and connectors. The multi segment builder accepts each segment independently and aggregates matched loss, connector loss, and mismatch loss across the full assembly. Per segment power output is shown so the contribution of each segment is visible.
No. The calculator runs entirely in your browser. No cable type, frequency, or installation data is submitted to a server. Useful for commercially confidential infrastructure work and environments where information security policy prohibits sending engineering data to third party services.
Cable loss contributes directly to the total system loss term in an EIRP calculation, and to the feeder loss line in a link budget. Use the Cable Loss Calculator to size the loss term, then carry that number into the noIM₃ EIRP Calculator for the radiated power, the Link Budget Calculator for full link feasibility, or the Antenna Power Density Calculator for human exposure compliance.
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