Verified calculation capability
Friis FSPL link budget with gains, misc loss, received power, and optional margin; optional u_* compose expanded uncertainty on Pr_dBm via Uncertainty Engine. · Electrical · Rf
Capability ID electrical.rf.link_budget · version 1.1.1
FSPL
FSPL = 20·log10(d)+20·log10(f)+20·log10(4π/c)Pr = Pt − (FSPL − Gt − Gr + L)Canonical symbols for this capability. Agent schemas remain the contract.
| Symbol | Quantity | Unit | Role |
|---|---|---|---|
Pt_dBm | — | — | input / output |
d | — | m | input / output |
f | Darcy friction factor | Hz | input / output |
Gt_dBi | — | — | input / output |
Gr_dBi | — | — | input / output |
L_dB | — | — | input / output |
S_dBm | — | — | input / output |
u_Pt_dBm | Optional standard uncertainty of Pt (dB) | — | input |
u_d | Optional standard uncertainty of distance (m) | m | input |
u_f | Optional standard uncertainty of frequency (Hz) | Hz | input |
u_Gt_dBi | Optional standard uncertainty of Gt (dB) | — | input |
u_Gr_dBi | Optional standard uncertainty of Gr (dB) | — | input |
u_L_dB | Optional standard uncertainty of L (dB) | — | input |
uncertainty_k | Coverage factor for expanded U on Pr_dBm; default 2 when any u_* is set. Requires at least one u_*. Mutually exclusive with confidence. | — | input |
confidence | Optional coverage probability instead of uncertainty_k. Requires at least one u_*. | — | input |
fspl_dB | — | — | output |
path_loss_dB | — | — | output |
Pr_dBm | — | — | output |
margin_dB | — | — | output |
wavelength | — | m | output |
uncertainty | Present when any u_* is provided; composed via engineering.uncertainty.propagate (sensitivity on Pr_dBm) | — | output |
Declared scope for this capability. Do not use it outside this domain.
Assumptions
One numerical check. The calculator page holds worked steps and FAQ.
Pt=20 dBm, 1 km, 2.4 GHz, S=-90 → Pr≈-80.05 dBm
CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance. Computational verification is defined by CVP. Supplemental domain review (internal) and named expert review are defined by the Review policy and do not by themselves determine CVP conformance.
Human page, REST, and MCP share the same engine and calculation_version.
Build verified hashes workspace artifacts only. After deploy, attest:production GETs canonical URLs twice — the public/cached view an Agent actually hits, and origin — including every /capabilities/{id} HTML page. Public Capability HTML version must match catalog before production attestation passes. Live Trust rows above fetch /.well-known/calculatorx-production-attestation.json
and the output schema const. Build hashes: release integrity. That proves currently published page / engine / schema / evidence / MCP agree — not that a historical version is independently immutable. Reference Calculation Standard — Production surface contract 6/6.
Human-readable sources plus CVP reference evidence classes.
Sources
Reference evidence classes: O1 model · O2 expected_values · O2 numerical_behavior
Inspect this capability via same-origin MCP, then call execute_calculation.
curl -sS -X POST 'https://www.calculatorx.com/mcp' \
-H 'Content-Type: application/json' \
-H 'MCP-Protocol-Version: 2026-07-28' \
-H 'Mcp-Method: tools/call' \
-H 'Mcp-Name: inspect_capability' \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"inspect_capability","arguments":{"capability_id":"electrical.rf.link_budget"}}}'
Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.1.1) when reproducibility matters. Full protocol notes: MCP docs.