Value chain · CLM-1128
In plain terms
A second test used a big radar dish in Massachusetts to light up a strip of LEDs on a tower over a kilometre away, with about a kilowatt flowing during each pulse; the receiver sat well inside the dish's near field, where the beam is uneven, and turned an estimated 60 per cent of the power reaching it into DC.
The claim as recorded
NRL's second 2022 demonstration used MIT Haystack's HUSIR radar, a "36.6 m circularly polarized Cassegrain antenna" whose "peak transmit power varies from 210 to 232 kW at 10.5 GHz when operated at a duty factor of 8.19%", to a "2.06 m x 2.19 m circularly polarized variant of the Blossom Point rectenna" at 10.5 GHz "installed 70.6 m above ground level at 1141 m away"; because "the 1.1 km link distance is only 1.2% of HUSIR's far field distance" the incident field is irregular and the best alignment gave "a maximum of 1030 W" into 30 ohm; driving a 0.3 x 1.1 m green LED display, "the pulse width is 1.638 ms, repeated at a 50 Hz rate", the in-pulse average "shows 215 V, which corresponds to 1.05 kW dissipated in the light display", the incident power estimated by scanning "as 1733 W, corresponding to 61% RF-to-DC conversion efficiency", a figure that "includes at least 0.3 dB of polarization mismatch loss" and which the authors rate more approximate than the Blossom Point result; the abstract states it as ">1 kW delivered at >1 km distance to a light display".
Evidence behind this: T1-peer-reviewed measured demonstration at higher duty; the authors themselves rate its efficiency "more approximate" than the Blossom Point figures.
Scope and limits
THE PAGE PRINTS "213 V and 1.03 W" FOR THE CONTINUOUS-OPERATION ESTIMATE (PDF 11, read at the zoom-5 crop): a 10^3 mismatch with the 215 V / 1.05 kW it sits beside, recorded as a suspected typesetting error in the source and not asserted as a disagreement; the record carries the measured 1.05 kW and does not repair the line. The conclusion prints "1.2 kW" (PDF 13, crop read) where the section gives 1030 W maximum into 30 ohm and 1.05 kW into the display and the abstract ">1 kW"; three statements of one result, recorded, the claim carrying the section's measured figure. Efficiency is the authors' "more approximate"; the element count and layout of the 2.06 x 2.19 m array are not given; 1.638 ms pulses at 50 Hz, not continuous.
What it assumes
The 1733 W incident is a phi-theta scan estimate with the same sensor and calibrated antenna as at Blossom Point, in a field the paper calls "complex and irregular".
Where it comes from
PDF 3 / printed 30: "36.6 m circularly polarized Cassegrain antenna" (normalised); "The peak transmit power varies from 210 to 232 kW at 10.5 GHz when operated at a duty factor of 8.19%" (normalised); "A 2.06 m x 2.19 m circularly polarized variant of the Blossom Point rectenna is designed at a center frequency of 10.5-GHz" (normalised). PDF 4 / printed 31: "installed 70.6 m above ground level at 1141 m away from the HUSIR transmitter" (normalised); "30.4 m above HUSIR's phase center" (normalised). PDF 10 / printed 37: "the 1.1 km link distance is only 1.2% of HUSIR's far field distance" (R1); "a maximum of 1030 W appears at" (normalised) phi = 196.2 deg and theta = 1.2 deg (Fig. 25 caption). PDF 11 / printed 38 (crop read): "the pulse width is 1.638 ms, repeated at a 50 Hz rate" (normalised); "shows 215 V, which corresponds to 1.05 kW dissipated in the light display" (normalised); "the LED voltage and power would drop to 213 V and 1.03 W, respectively" (normalised); "scanning as 1733 W, corresponding to 61% RF-to-DC conversion efficiency" (R1); "includes at least 0.3 dB of polarization mismatch loss between HUSIR and the rectenna" (normalised); Fig. 26c (render reading, figure text not in the layer): a 215 V pulse of about 1.6 ms, labelled in the figure as 215 V and 1.05 kW. PDF 1: "demonstrates >1 kW delivered at >1 km distance to a light display" (raw). PDF 13 / printed 40 (crop read): "In addition, 1.2 kW of electrical power was delivered to an LED display at 1.1 km" (normalised). Recomputed: 1.638 ms x 50 Hz = 0.0819, the stated duty; 2 x 36.6^2 / 0.02857 = 93,800 m, 1,141 / 93,800 = 1.2 per cent; 1.05 / 1.733 = 60.6 per cent; 1,050 / 215 = 4.9 A; 1.05 kW x 0.0819 = 86 W average, where Fig. 27 plots the HUSIR LED average near 90 W; 2.06 x 2.19 = 4.51 m2.
Basis: m; kW; GHz; per cent duty; ms; Hz; V; W; per cent RF-to-DC
Related records
- Answers question
- QST-002 not published in this release
Cite this
energyaperture.com/c/clm-1128
CLM-1128, Energy Aperture, as of 2022-01.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-270
- CLM-1122About twenty thousand postage-stamp-sized antenna-plus-diode cells, each with an off-the-shelf microwave diode, wired into tiles, then...CLM-1123A five-metre dish and a 100 kW radar-type pulsed tube a kilometre away, bounced partly off the ground on purpose to get more power onto the...CLM-1124One panel the size of a sheet of paper turned about seven-tenths of the microwave power landing on it into DC, and did best at about three...CLM-1125Four square metres of receiver turned 73 per cent of the microwave power arriving at it into 1.65 kW of DC, measured a kilometre from the...CLM-1126They deliberately fried each of the four panels with ever-stronger pulses. A bare panel gave up at 672 watts out; clamping its voltage with...CLM-1127As flown, under two per cent of the microwave power fed to the dish came out of the receiver as electricity, because the beam had to be...CLM-1129The authors say the 1975 record still stands at twenty times their power, that the custom diodes which set it no longer exist, and that...CLM-1130A quick way to size a ground-to-ground beam: at the distance where the dish stops focusing, the cone holding half the power is about twice...More on the source page.