Tellurometer
microwave electronic distance measurement equipment
The tellurometer was the first successful microwave electronic distance measurement equipment. The name derives from the Latin tellus, meaning Earth.
History
The original tellurometer, known as the Micro-Distancer MRA 1, was introduced in 1957. It was invented by Trevor Wadley of the Telecommunications Research Laboratory of the South African Council for Scientific and Industrial Research (CSIR). He was also responsible for the Wadley loop receiver, which allowed precision tuning over wide bands, a task that had previously required switching out multiple crystal oscillators.
Principle
The tellurometer emits a microwave-frequency radio wave. The remote station carries a transponder that reradiates the incoming wave in a similar wave of more complex modulation. The resulting phase shift is a measure of the two-way distance travelled. The results appear on a cathode ray tube with circular sweep.
Application
The tellurometer design yields high accuracy distance measurements over geodetic distances, but it is also useful for second order survey work, especially in areas where the terrain is rough and/or the temperatures extreme.
“Tellurometer” enters the record as microwave electronic distance measurement equipment. Crown Archives preserves that source wording while asking what Tellurometer, microwave and electronic can confirm, complicate or overturn.
Why this record matters
“Tellurometer” is worth following because a concise public description often conceals a longer documentary argument. Here, Tellurometer, microwave and electronic provides the most credible route into that argument.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Feb 12, 2026. The linked authority identifier is Q1362844. The first chronological checks are 1957.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. 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.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Tellurometer”, its source revision and the description used here.
- Expand the search: follow Tellurometer primary sources, Tellurometer archive and Tellurometer research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Tellurometer”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Tellurometer” 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.