Value chain · CLM-0961
In plain terms
Everything in the 1975 interference analysis is for one satellite. The study itself says that a hundred of them would raise the noise and harmonics a hundredfold - 20 decibels - and that nobody had looked at what that would mean.
The claim as recorded
The study states that its interference analysis is for one satellite delivering 5 GW to the ground, and that "For additional systems, e.g., 100, the noise and harmonics generated would increase by 20 dB", with the impact requiring further in-depth investigation. That is the multi-satellite caveat SRC-111's Point II carries as "the severity of the problem increases directly with total transmitted SPS power" - here with the number attached.
Evidence behind this: T3-primary-report. A stated scaling with no derivation, from the study that did the single-satellite analysis.
Scope and limits
STATED WITHOUT DERIVATION AND NOT EVALUATED. Nothing in the section works the 100-satellite case; the sentence is a scaling rule and a pointer to work not done. Incoherent addition is the natural assumption for noise from independent transmitters and the wrong one for any component that is coherent across satellites, which the study does not discuss. Every limit-line comparison in CLM-0959 and CLM-0960 is therefore a single-satellite comparison, and a deployment of the size the 1970s programme contemplated would sit 20 dB higher against every criterion.
What it assumes
Incoherent addition of noise and harmonics across satellites, which the study states without derivation.
Where it comes from
PDF p.52, verbatim at the normalised level: "For additional systems, e.g., 100, the noise and harmonics generated would increase by 20 dB." 10 log(100) = 20 dB is incoherent power addition across satellites. SRC-111 read directly: PDF p.9, normalised, "The severity of the problem increases directly with total transmitted SPS power. The impact on potential victim systems has not been evaluated in detail."
Basis: dB
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-0961
CLM-0961, Energy Aperture, as of 1975.
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-0919In 1978 there was no rule allowing a solar power satellite to transmit power, and the industrial band everyone assumed it would use permits...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-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...
- Also from SRC-451
- CLM-0954The 1975 designers worked out how much their kilometre-wide antenna would bend, precisely so they could decide how good the beam-steering...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-0965In 1973 an astronaut on Skylab put together two long poles from short sections in just over two hours, about six minutes per join. A 1975...CLM-0966In 1975 the antenna alone was expected to take one to two years to assemble in orbit with about fifty people, and robot arms were judged...CLM-0968The 1975 antenna study worked out how hot the middle of the transmitter gets depending on how efficient the tubes are and how tightly they...CLM-0969If the tubes are only 70 per cent efficient, the transmitter's own face is not big enough to get rid of the heat they make, even spread...CLM-0972If you take a 1975 estimate of how fast people could build structure in space, checked against one Skylab task, and apply it to the 1978...More on the source page.