Electronics > RF, Microwave, Ham Radio

strange interaction between radio and zinc (arecibo telescope collapse)

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coppercone2:
Also, this document is more riveting then the best horror novel


I was wondering about how that thing managed to screw off so hard.

https://gizmodo.com/jaw-dropping-report-reveals-causes-of-arecibo-telescope-collapse-2000517284

“The only hypothesis the committee could develop that provides a plausible but unprovable answer … is that the socket zinc creep was unexpectedly accelerated in the Arecibo Telescope’s uniquely powerful electromagnetic radiation environment.”

Ah zinc, aluminums drunkard cousin, always causing trouble.  :o

It makes me think about the common parallel of 'do it yourself mechanical engineers' making creative low cost interconnect/electromechancial 'integration' in their designs to get rid of electrical hardware and the usual hilarious results, though in this case I think it really must have been something new, its too expensive and well studied to compare to a cheap flashlight.


Full report:
https://nap.nationalacademies.org/read/26982/chapter/1#xiv


Here is a spelter socket


It was always one of those things that told me 'stay away from cranes'. Their all over and seemingly safe, but I get the hebee jebees from that design.




Some basic insight that people might not realize to help understand why zinc is used instead of lead, which we all know and trust
-zinc is actually really strong. Its the one metal that melts easy, has a high tensile strength and its angry enough to bust through alot of oxides an stuff (making it a choice for aluminum soldering). Cleans nicely with HCl to form zinc chloride, which is a great soldering flux!

so for high tensile strength applications, zinc is actually pretty good, even though its kind of nasty to work with.


One idea that popped in my head is if process changes occurred. Like trying to get rid of HCl to make assembly greener or something.
I think I saw wire pull out of a solder joint when it was yanked before. Like, there was a joint (dirty) but the wire was firmly seated, however you can 'yank' it out slowly if you did not apply too much pressure to it. I wonder if there can be a situation where there is a mechanical friction bond to a rough wire.. then you have zinc change its crystal structure over time and gradually lose the mechanical bond.

I know its difficult because it took me a while to figure out how to get DIY lead hammers correct, which initially used lead cast over a shape. in the end I drilled a hole and put a bolt through it, then cast that into place, and it was much more secure then trying to get it to 'envelop' something smooth. I wonder if you can etch steel cable so the zinc adheres to it better too. I don't think its supposed to actually wet the cable, like my observation with the solder joint, its supposed to work like that dodgy solder joint...? Lol, or little bits of zinc soldered to the cable, stuff diffused making harder rough spots, and the rocking of the wind gradually broached it loose.

But what role did the RF play???

And how did you personally experience bureaucratic delays in decaying facilities ? personally I have seen
-flickering lights
-scary motor noises
-decreased food quality
-malfunctioning doors
-intralab furniture theft



Also, this article seems to support my theory that the eifel tower is good :-//

LM21:
Did Arecibo  transmit  too. I thought it  was only listening, or mostly so. Listening weak signals  does not cause  strong fields IMO. Everybody knows  this or what?

coppercone2:
its a terawatt or more microwave radar


they mapped the moon with it. very powerful.

I don't think they built it in a way that it picks up more then some gentle side lobes on the cabling because thats a gigantic waste of money


that is a interesting point though, I wonder if there could have been some alignment mishap that caused it to irradiate its own structure somehow. i think they do some very high peak power tests. maybe they blasted it by accident and no one noticed. And call me paranoid but when I think of TW transmitters I start thinking maybe someone was nervous about it, like sabotage or some experiment gone wrong. I always thought it might have something to do with stealth technology development (perhaps someone thought it might be looking for stealth satellites in its time off). It always makes me wonder when a proven technology suddenly has a ton of gremlins for no good reason.


But the reasonable explaination seems to be that zinc is electroplastic and it can weaken zinc bonds from continous low currents, possibly more so then usual based on some manufacturing change of the cable bond over 50 years.

Andy Chee:

--- Quote from: LM21 on November 05, 2024, 01:05:16 pm ---Did Arecibo  transmit  too. I thought it  was only listening, or mostly so. Listening weak signals  does not cause  strong fields IMO. Everybody knows  this or what?

--- End quote ---
Arecibo has transmitted before in the past, most notably;

https://en.wikipedia.org/wiki/Arecibo_message



But Arecibo mainly functioned as a receive only antenna for radio astronomy.

For transmitting signals to Mars rovers, Voyager, or New Horizons Pluto, a separate dedicated network of dishes that comprise the Deep Space Network, is used to maintain communications, which avoids tying up radio astronomy dishes.

coppercone2:
The average power is approximately 150kW with instantaneous power in the megawatts and focused peak power in the terrawatts (antenna power)

But if it was due to instantaneous peak effects I think they would see some shit go down there like in a microwave oven and it would be loud and sparky and there would have been soot inside of their cross section cutaways

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