Value chain · CLM-1063
In plain terms
In 1980 the magnetron satellite was the lightest per kilowatt on paper and the most efficient tube on the bench, the klystron was the panel's safer bet on noise and voltage, and the panel warned that every efficiency budget so far used the most optimistic number for the tube.
The claim as recorded
The tube choice was open at the April 1980 Program Review and the two contractors' comparison table made the magnetron the lowest in specific mass (kg/kW): reference GaAs concept 31.6 x 10^6 kg and 6.2 kg/kW (multibandgap 26.0 and 5.1), magnetron concept 0.92 km antenna, 28 kW/m2, 11.0 km rectenna, 5.6 GW, 26.7 x 10^6 kg and 4.8 kg/kW (21.5 and 3.8), solid-state end-mounted 1.4 km antenna, 6.6 kW/m2, 7.5 km rectenna, 2.6 GW per antenna, 40.0 x 10^6 kg and 7.7 kg/kW (35.6 and 6.8), solid-state sandwich at concentration 5.2, 1.8 km, 0.70 kW/m2, 4.8 km, 1.2 GW per antenna, 20.5 x 10^6 kg and 8.5 kg/kW (16.4 and 5.40), with the text "Magnetron concepts appear to have the best combination of characteristics, but development is needed to determine whether predicted lifetime and efficiency goals can be obtained"; the tube developer put achieved efficiencies at 75 per cent for the klystron and "83 to 85%" for magnetrons and amplitrons; and the January 1980 review panel held that "At this time the klystron looks most favorable, but either the solid state or magnetron source may look better later", that "If it is not possible to operate at 40-50 kV, then klystrons cannot be used", that "it appears that the klystron will have better noise characteristics than the solid state or magnetron devices", and that "In the efficiency budgets produced so far, only the most optimistic predicted values have been used for the estimates of DC to rf conversion".
Evidence behind this: T3, the contractors' concept comparison table read from a render, the tube developer's achieved efficiencies, and the review panel's judgments.
Scope and limits
A comparison table with no mass statements behind it; the panel's noise judgment ("it appears") is stated against the same month's Raytheon measurements it did not have (CLM-1044).
What it assumes
The table's kg/kW is per kW at the utility interface, as its row header says.
Where it comes from
PDF p.120 / printed 97, Table 1 "Concept Comparisons", render read: rows and columns as stated (GaAs and MBG per concept; "SATELLITE MASS (10^6 kg)"; "SATELLITE SPECIFIC MASS (kg/kW)"; magnetron life stated on PDF p.119 / printed 96 as "up to 30 years compared to ten years for klystrons between replacements"); text as quoted. PDF p.358 / printed 336, render read: the efficiency sentences (CLM-1058). PDF p.367 / printed 345, normalised: "There is still no definite answer as to which choice is optimum for the microwave power amplifier devices. At this time the klystron looks most favorable, but either the solid state or magnetron source may look better later"; "If it is not possible to operate at 40-50 kV, then klystrons cannot be used. While ohmic and klystron efficiencies increase at higher voltage, reliability of power conditioning equipment and the klystrons decreases. Water cooling of the klystron looks troublesome"; "Noise and harmonic generation is a major problem with any of the power amplifiers being considered; however, it appears that the klystron will have better noise characteristics than the solid state or magnetron devices." PDF p.368 / printed 346: "Injection-locked magnetrons may offer substantial promise from a cost point of view, however, substantial work needs to be done at the device level in the area of noise reduction and improved efficiency"; "In the efficiency budgets produced so far, only the most optimistic predicted values have been used for the estimates of DC to rf conversion. A more conservative approach would be to use demonstrated efficiencies, with the variabilities of loading and performance included."
Basis: 10^6 kg satellite mass; kg/kW at the utility interface; per cent efficiency
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-1063
CLM-1063, Energy Aperture, as of 1980-04.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-449
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