Talk:Arecibo Telescope

General Information - Transmitter Power Output

--The General Information section appears erroneous, lacks proper reference, and requires update.

    "The telescope had three radar transmitters, with effective isotropic radiated powers (EIRPs) of 25 TW (continuous) at 2380 MHz, 3.2 TW (pulse peak) at 430 MHz, and 200 MW at 47 MHz,[12] as well as an ionospheric modification facility operating at 5.1 and 8.175 MHz.[13]"

--The sited source ("Arecibo Call for Ionospheric Modification (HF facility)Proposals–2018")states:

    "The HF facility at Arecibo transmits a maximum of 600KW at 5.1MHz, with 22 dB of gain and 13 deg. of half power beam width, or 8.175MHz with almost 26dB and 8.5 deg. The HF transmission has a Cassegrain design where the primary is the 300 m Arecibo dish, the secondary is a sub-reflector mesh that reflects frequencies lower than 20MHz, and the feed system is composed of an array of three concentric cross dipole antennas at each frequency. The transmitters are connected to the antenna arrays by coaxial lines."

--While there was a klystron upgrade and the size of the antenna can make for large numbers, the way the data is presented is misleading, may not be accurate, and lacks proper reference.

--The transmitter O&M manual (last updated in 2005) posted by NAIC.edu states:

    "Two Litton L-3403 or L-5773 klystrons operate in parallel as a balanced amplifier, with a 90-degree power splitter at the input and a high-power 90-degree combiner at the output, to provide a maximum total peak pulse output power of 2.5 MW."

--While it's possible that the O&M manual doesn't include the latest upgrades, I don't see any evidence that the upgrades were anything more than receiver related.

71.139.117.78 (talk) 18:12, 3 December 2020 (UTC)JAK

If you look at the cited pages in the O&M manual, you will find it says:

EIRP: the 430 transmitter supplies about 2MW peak power up to the antenna. The antenna has a

62dB gain, so the EIRP is 2 x 106.2 MW = 3.2 million Megawatts peak. The average 430 MHz EIRP is 6% of the peak or 224,000 Megawatts.

Beamwidth: is given by lamda/dish diameter = .7m/300m = .0023 radians = 0.13 degrees.Other Arecibo transmitting systems, for comparison:

The S-band transmitter supplies 1MW (peak and average) to the antenna. The gain is 74dBso the EIRP is 1 x 107.4 MW = 25 million Megawatts.

The beamwidth of the 2380 radar system is 1.9 arc minutes or 0.032 degrees.

The 46.8 MHz transmitter supplies the antenna with 40kW peak and 2 kW average. The gain is around 37dB (assuming the yagi feed produces an aperture efficiency of 25%), so the EIRP is 40kW x 103.7 = 200,000 kW peak and 10,000 kW average.

The beamwith at 46.8 MHz is 6.4/300 = .02 radians or 1.2 degrees.

The figures given in the section thus match those given in this source. As noted in an earlier discussion (on the Arecibo Observatory article talk page), the S-band EIRP is slightly overstated in this source but that is a different issue from whether the section is leaving in proper references, which it clearly is not. Robminchin (talk) 03:10, 4 December 2020 (UTC)

Reference in Battlefield 4 under the popular culture section

https://battlefield.fandom.com/wiki/Rogue_Transmission

The telescope features in this level, though is said to be of Chinese origin referencing the FAST telescope which was under construction at the time of the game's publication. It is however based on Arecibo as ca be seen bu the 3 supporting towers (versus 6 on FAST) and shallower dish compared to FAST, and the appearance of the Gregorian sub-reflector on the hanging structure. Through "levelution" the telescope in game can also be made to collapse by destroying the supporting cables, exactly sa events transpired over the course of 2019/2020 — Preceding unsigned comment added by 45.91.17.10 (talk) 18:24, 3 December 2020 (UTC)

We can't use fandom.com - that's a user-generated source. I have found and included a RS that mentions that the game has a level based on the telescope which is all that we need to say, we don't need to go into any further detail. --Masem (t) 18:27, 3 December 2020 (UTC)

Dondoulakis dispute

The paragraph discussing the Dondoulakis dispute is extremely difficult to follow. Someone familiar with this episode should rewrite it.Bill (talk) 02:06, 9 August 2021 (UTC)

Bill, I couldn't agree more. I helped with the late author's archiving of his posthumous memoir, "The Arecibo Antenna," and finding the references at Cornell, in the NY Herald Tribune, and NY Times. He himself wrote a note on the Arecibo Observatory's Talk Page, when he was 85 (see 15 Feb 2007 ... https://en.wikipedia.org/wiki/Talk:Arecibo_Observatory).

I was prohibited in using his book as a reference when attempting to clarify the page as you suggested.

Any further help would be deeply appreciated, as well as by the Wiki community.

Cheers,

Eli Bigeez (talk) 02:19, 23 November 2022 (UTC)

Featured picture scheduled for POTD

Hello! This is to let editors know that File:Collapse of Arecibo Radio Telescope 01.webm, a featured picture used in this article, has been selected as the English Wikipedia's picture of the day (POTD) for December 1, 2023. A preview of the POTD is displayed below and can be edited at Template:POTD/2023-12-01. For the greater benefit of readers, any potential improvements or maintenance that could benefit the quality of this article should be done before its scheduled appearance on the Main Page. If you have any concerns, please place a message at Wikipedia talk:Picture of the day. Thank you!  — Amakuru (talk) 14:06, 3 July 2023 (UTC)

The Arecibo Telescope was a 305-meter-diameter (1,000 ft) spherical-reflector radio telescope built into a natural sinkhole at the Arecibo Observatory located near Arecibo, Puerto Rico. A cable-mount steerable receiver and several radar transmitters for emitting signals were mounted 150 meters (492 ft) above the parabolic antenna. Completed in November 1963, the Arecibo Telescope was the world's largest single-aperture telescope for 53 years, until it was surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China. Following a long period of declining maintenance exacerbated by Hurricane Maria and two earthquakes, the Arecibo Telescope's receiver cables suffered a catastrophic failure that culminated in the collapse of the receiver platform at around 6:55 a.m. AST (10:55 UTC) on December 1, 2020, as captured in this video. The collapse of the receiver structure and cables onto the dish caused extensive additional damage, and ultimately resulted in the decision to demolish the remaining structure in 2022.

Video credit: National Science Foundation

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