RF link budget calculator

Logarithmic link budget; gains/losses are dimensionless dB values.

rf-link-budget.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	receivedDbm	marginDb
	-68	22
	-70	20

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

link margin target22.00 ✓ passes

BASELINE INPUTS

transmitDbm10 transmitGainDb2 receiveGainDb2 pathLossDb80 otherLossDb2 sensitivityDbm-90

CALCULATED

receivedDbm-68

marginDb22

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# RF link budget
# Scope: Logarithmic link budget; gains/losses are dimensionless dB values.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

transmitDbm = 10
transmitGainDb = 2
receiveGainDb = 2
pathLossDb = 80
otherLossDb = 2
sensitivityDbm = -90

receivedDbm := transmitDbm+transmitGainDb+receiveGainDb-pathLossDb-otherLossDb
marginDb := receivedDbm-sensitivityDbm

check link margin target: marginDb >= 10

scenario alternative: transmitDbm = 8

Calculated from your source · not saved

Baseline · Baseline

link margin target22.00 ✓ passes

alternative · alternative

link margin target20.00 ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

received dbm: receivedDbm = transmitDbm+transmitGainDb+receiveGainDb-pathLossDb-otherLossDb
margin db: marginDb = receivedDbm-sensitivityDbm

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

transmit dbm: 10
transmit gain db: 2
receive gain db: 2
path loss db: 80
other loss db: 2
sensitivity dbm: -90

Calculated

received dbm: -68
margin db: 22

Assumptions and limits

Logarithmic link budget; gains/losses are dimensionless dB values.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: RF link budget. Inputs: transmit power; antenna gains; losses; receiver sensitivity. Outputs: received power; link margin. Model scope: Link and transmission models with declared propagation assumptions. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: transmit power, antenna gains, losses, receiver sensitivity
Outputs: received power, link margin
Modes: calculate, compare, sweep
Drawing: Link-budget and coverage plots

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS