Distance Loss

Expected loss for a run of P3, QR, RG6, RG11 or RG59 cable.

Cable type Length ft Frequency MHz

Expected loss

–dB

Across the band

Freq	dB/100 ft	Run loss

House Calculator

Tap → ground block → outlet/CPE, with separate cable for each leg.

Tap → GB cable GB → CPE cable Tap → GB ft GB → CPE ft Frequency MHz Splitter / device dB

Total expected house loss

–dB

Signal Levels

Actual loss from dBmV readings. Fill in any two points. Use ± for negative levels.

Tap level dBmV Ground block level dBmV CPE level dBmV

Measured loss

–dB

Enter at least two levels.

AGC Back-Off

Manual back-off from the temperature chart. Uses the shared temperature unless you type one here.

Temperature °F Frequency

Manual back-off

–dB

Full chart

All frequencies

747 MHz is interpolated between 547.25 and 870 MHz. 1218 MHz is extended from the 870 → 1 GHz slope.

Plant Power

Voltage at each device down a powered CATV chain.

Power supply VAC Minimum good VAC Default cable Default current A Load model Current rated at VAC

Lowest device voltage

–VAC

Device chain

Supply → first device → …

Each span carries the current of every device after it. Cable resistance is CommScope's nominal DC loop resistance at 68°F, corrected for the temperature you set at the top of the page (+0.4% per °C). Realistic (constant power): actives draw more current as their voltage drops. Enter each device's current as rated at the "Current rated at" voltage. Fixed current: current stays the same (the older, simpler model). Device types fill in a typical current, which you can edit.

Cable Types

Attenuation per 100 ft at 68°F from the built-in charts, plus hardline loop resistance.

* Beyond the cable's published chart, so extended from the last two points.

P3 hardline

500, 625, 750, 875. Feeder and trunk.

QR hardline

540, 715, 860. Feeder and trunk.

Drop

RG6 and RG11 for tap to ground block and inside runs.

Outlet / legacy

RG59 for older outlets and legacy inside wiring. Check it first on 1.2–1.8 GHz trouble.