CACrown ArchivesThe cinema collection
EN/FR
Search
Menu
Research dossier · General Reference

Thermal fade

Open-knowledge reference entry

Cross-disciplinary reference desk with index cards, atlas, dictionary and catalogue
General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionMar 1, 2026
Entity authorityQ7783049 ↗
Source-derived summary

A thermal fade is a phenomenon of wireless signal degradation (fading) caused by temperature and relative humidity factors. As the prevailing environmental conditions change (e.g., from hot to cool, humid to arid, or day to night), the electromagnetic waves refract differently, thus altering the power distribution and possibly the direction of the signal. This is the same process that causes visible light to "bend" over a heated road or other surfaces on hot days.

Thermal fade primarily affects very and ultra high frequencies, regardless of modulation method (AM, FM, etc.). The thermal fade margin is calculated from subtracting losses from antenna gains. A higher fade margin is required in humid locations, and lower in dry ones.

See also

Atmospheric duct

Refractive index

Thermal degradation of polymers - sometimes referred to as "thermal fade".

Editorial summary

Begin with the source’s own compact description: “Thermal fade” is open-knowledge reference entry. The dossier treats that line as a proposition to test through Thermal, fade and Open-knowledge, not as a finished interpretation.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current 133-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. For this dossier, Thermal, fade and Open-knowledge is the immediate research focus.
Editorial analysis

Why this record matters

The phrase “open-knowledge reference entry” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.

Evidence profile

Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Mar 1, 2026. The linked authority identifier is Q7783049. None of the 0 selected statements returned an explicit reference.

Critical limits

The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

Best used for
  • Subject orientation
  • Search vocabulary
  • Locating named sources
Verify next

The closest primary source, responsible institution and strongest cited specialist reference.

Three-step research path

  1. Establish the record: confirm the title “Thermal fade”, its source revision and the description used here.
  2. Expand the search: follow Thermal fade primary sources, Thermal fade archive and Thermal research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

  1. Which source most directly establishes the central claim about “Thermal fade”?
  2. Which institution is responsible for the underlying evidence?
  3. Which cited source is closest to the event, object or claim?
Subject index

Search terms from this dossier

Source & attribution

This entry incorporates text from “Thermal fade” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.