Value chain · CLM-0919
In plain terms
In 1978 there was no rule allowing a solar power satellite to transmit power, and the industrial band everyone assumed it would use permits unlimited power only on the exact frequency while separately forbidding the spurious and harmonic emissions the same report expects. A ground-based industrial heater interferes to the horizon; a satellite covers half the planet.
The claim as recorded
The 1978 EMC assessment states that SPS microwave power transmission would require modification of existing international radio rules, that no provision for it then existed, and that a logical extension of existing rules might preclude it. It identifies the specific mismatch: the ISM designation the SPS studies assumed rests on ITU Article 5 footnote 357, under which emissions must be confined within 50 MHz of 2450 MHz and radiocommunication services inside those limits must accept harmful interference from ISM equipment - while the FCC defines ISM equipment as not used nor intended for radio communication, permits unlimited radiation on the ISM frequency itself, and separately forbids harmful interference to authorised services from spurious or harmonic radiation. The assessment notes that the 2400-2500 MHz band is not allocated to ISM throughout the world, and that an ISM installation's interference is limited by line of sight whereas an SPS would cover roughly a hemisphere.
Evidence behind this: Government-contractor assessment read directly in the held file. The document is headed PRELIMINARY DRAFT on its own contents page (PDF p.5, printed i; the title pages, PDF pp.1 and 3, do not carry it) and that standing applies here as it does to CLM-0918.
Scope and limits
A 1978 PRELIMINARY DRAFT'S READING OF 1978 RULES, AND THE RULES HAVE MOVED. ITU Article 5 footnote 357 and the FCC Part 18 sections are as they stood in 1978 and may not be cited as current text. The register's modern position on the same question is CLM-0120 and CLM-0552, which record that no ITU allocation or protection criterion exists for space-to-Earth wireless power transmission and that Resolution 910 (WRC-23) directs studies toward WRC-31. THIS RECORD DOES NOT ESTABLISH THAT THE 1978 GAP AND THE 2023 GAP ARE THE SAME GAP - it establishes that a gap was identified in both, forty-five years apart. THE POINT IV PAGE IS TRANSCRIBED, NOT QUOTED, and a reader relying on its exact wording must open the file. The document also names a 1979 WARC as the venue that could change the rules; whether it did is not established here. The programme's own account of the 1979 WARC is now held (CLM-1091, from the 1980 Boeing summary): no frequency assigned, with the US able to seek one if the system were shown environmentally safe; one paragraph, no WARC document cited (back-linked 2026-09-18).
What it assumes
No assumptions are recorded against this claim.
Where it comes from
THE POINT IV PAGES ARE A BADLY DEGRADED SCAN AND THESE ARE TRANSCRIPTIONS, NOT VERBATIM QUOTATIONS. The raw rendering is given so a reader can check rather than trust. Point IV itself, PDF p.11 (printed -5-; earlier written as a zero-based index 10), renders as "SPS micro\vave power transmissicn will require modification of existi~g int2rnational radio rules. There is at present n~ prodisicn '(;r :'?TS 3psration and logical extension of existing rules might preclude it." Transcribed: "...no provision for MPTS operation and logical extension of existing rules might preclude it." The discussion, PDF p.31 (printed -25-), is cleaner and these ARE verbatim: "The frequency 2450 MHz is designated for industrial, scientific and medical purposes except in Albania, Bulgaria, Hungary, Poland, Roumania, Czechoslovakia and the U.S.S.R., where the frequency 2375 MHz is used." - the same passage renders the tolerance as "confined within i 50 MHz", where "i" is the scan's rendering of the plus-or-minus sign. Verbatim: "Radiocommunication services operating within these limits must accept any harmful interference that may be experienced from the operation of industrial, scientific and medical equipment." Verbatim, FCC 18.3(f): "Devices which use radio waves for industrial, scientific, medical, or any other purpose including the transfer of energy by radio and which are not used nor intended to be used for radio communication". Verbatim, 18.102(b): "Equipment operating on an ISM frequency may be operated with unlimited radiation on that frequency." Verbatim, 18.14(c): "No harmful interference shall be caused to authorized communications services from spurious or harmonic radiation". TWO OF THOSE SIX DID NOT MATCH ON FIRST SEARCH AND BOTH WERE A77: the scan renders "communi- cation" and "ser- vices" with a hyphen and a space, which ordinary de-hyphenation does not join. Hemisphere comparison, PDF p.32 (printed -26-), verbatim: "The area of interference produced from an ISM installation at the surface of the earth is limited by line of sight propagation characteristics at microwave frequencies whereas an SPS would cover roughly a hemisphere." A59 CONTROLS FROM THE SAME EXTRACTION: ISM 8, 2450 MHz 2, 2375 MHz 1, 18.3 1, 18.102 1, 18.14 1. CORROBORATED FROM A SECOND HELD DOCUMENT, 2026-09-15, AND WITH THE ALLOCATION TEXT ITSELF. SRC-450 PDF p.32 reproduces the wording SRC-111 paraphrases, verbatim at the normalised level: "The frequency 2450 MHz is designated for industrial, scientific and medical purposes except in Albania, Bulgaria, Hungary, Poland, Roumania, Czechoslovakia and the U.S.S.R., where the frequency 2375 MHz is used. Emissions must be confined within +/-50 MHz of the frequencies designated. Radiocommunication services operating within these limits must accept any harmful interference that may be experienced from the operation of industrial, scientific and medical equipment." The 5800 MHz designation follows with +/-75 MHz and the same acceptance clause. SO THE MISMATCH THIS RECORD IDENTIFIES IS NOW ATTESTED BY THE ALLOCATION'S OWN TEXT AND NOT ONLY BY AN ASSESSMENT'S SUMMARY OF IT. AND A SHARPER POINT THE SAME PAGE SUPPLIES. SRC-450 PDF p.33 lists ITU Master Frequency List station registrations for communication in 2400-2500 MHz by England, West Germany, Holland, France, Belgium, Czechoslovakia, Austria, the U.S.S.R., Yugoslavia, Sweden, Turkey and Mexico, and in 5725-5875 MHz by seven states - with a footnote marking the band as "Not an industrial band in these countries" for Czechoslovakia and the U.S.S.R. Those two therefore hold communication registrations in a band that is not ISM for them, so the acceptance clause above does not reach them. Some English and Dutch registrations are troposcatter stations, "which have large antennae and are especially sensitive to interference" - raw, and the surrounding sentence renders as "for communcation purnoses", which is why that phrase is reported rather than quoted. This is a 1977 snapshot of the List and nothing here establishes its current state.
Basis: MHz (band edges)
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-0919
CLM-0919, Energy Aperture, as of 1978-02.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-111
- CLM-0918The 1978 study of what a solar power satellite would do to the radio spectrum found two things. Its transmitter NOISE would exceed what...CLM-0920The 1978 study says a solar power satellite cannot keep its beam entirely on the receiving station - the physics of beams forbids it - so...CLM-0921The 1978 report says the power density a solar power satellite apparently needs to make economic sense was thought to be about the same as...CLM-0959The original 1975 calculation found the satellite's radio noise would be fine for ordinary and troposcatter radio links and a problem only...CLM-0960The 1975 study found the satellite's harmonics - the multiples of its transmit frequency - would trouble radio astronomy at the second and...CLM-0961Everything in the 1975 interference analysis is for one satellite. The study itself says that a hundred of them would raise the noise and...CLM-1315The 1975 estimate of the satellite's radio noise, taken at its own frequency, is about a hundred million times above today's threshold for...