Value chain · CLM-0931
In plain terms
A 1989 NASA workshop records that the receiving antenna on the ground is not just a receiver - it radiates too. One contribution lists harmonic radiation as a negative feature of the current design. Another reports that on a microwave-powered aircraft, by inference the Canadian SHARP aircraft that first flew on microwave power in 1987, the receiving antenna was noisy in three different ways, and that Canadian regulators nearly stopped the test flight over interference concerns.
The claim as recorded
The rectenna is itself an emitter, and this is stated twice in one volume - once as a design property and once as reported flight experience. In a table of the rectenna's characteristics under Negative Factors: "Current design radiates harmonics - new design would not". And in the Near-Earth Applications discussion summary, reporting a "Microwave-powered airplane" - by inference the Canadian SHARP aircraft, which PDF p.179 says made the first successful free flight on microwave power in 1987, although the summary itself names Canada and not SHARP - Canada "almost prevented test flight out of concern over microwave EMI", and "The rectenna was noisy (intermodulation, parasitic oscillations) and subject to spurious signal amplification and re-emission." That names three distinct emission mechanisms - intermodulation, parasitic oscillation and spurious re-emission -. The rectenna as a source of harmonics, noise and spurious radiation is already in SRC-111 (1978), PDF p.22; what this volume adds is the report from an aircraft in flight. It is also the only instance in this register of an electromagnetic-compatibility concern actually constraining an operation.
Evidence behind this: NASA conference publication, 438 pages, 28 contributions. Quotations matched RAW on registration. The text layer carries the SRC-111 hazard classes - letterspaced runs, hyphen-space joins and lone-token lines - so the quotations were taken from rendered pages and confirmed against the text layer.
Scope and limits
THE SHARP REPORT IS A DISCUSSION SUMMARY OF AN UNSCHEDULED PRESENTATION, NOT A TEST REPORT. It is a second-hand account within a workshop proceedings; no measurement, no level, no bandwidth and no frequency is given for any of the three mechanisms, and nothing here quantifies the emission. "Almost prevented" is the summary's characterisation and the register holds no regulatory record of the episode. A 1989 aircraft rectenna at low power is not a 1 km ground rectenna, and whether these mechanisms scale, worsen or vanish at rectenna scale is not established by anything held. The harmonics line is design commentary from 1989 and explicitly says a new design would not radiate them - so it is a statement about one generation of hardware, not a permanent property.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
Read first-hand on registration, all matched raw. Verbatim, from the rectenna characteristics table under Negative Factors (PDF p.180): "Current design radiates harmonics - new design would not". Verbatim, Near-Earth Applications discussion summary (PDF p.424 and p.425), under "Microwave-powered airplane"; it names Canada but not SHARP, which is named only on PDF p.179, so the identification is inference: "almost prevented test flight out of concern over microwave EMI" and "The rectenna was noisy (intermodulation, parasitic oscillations) and subject to spurious signal amplification and re-emission." CONTROLS FROM THE SAME EXTRACTION: rectenna 56, microwave 83, SHARP 4 across 438 pages.
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-0931
CLM-0931, Energy Aperture, as of 1989.