Happy Saturday all. Follow-up on the original Kiev clip: I think the sound was real

and came from building or paving work beside the filmer's block, not a hoax or a sample. I can't name the machine, and some of this is soft, so I've flagged what is.
Same tones on two different days
The 3 Aug (84V5eySzQf0) and 11 Aug (vcUDYBIrWio) uploads are different audio with the same tones, about 134, 214, 271, 405 and 537 Hz. The uploader's own 2011 forum post lists 140/211/397/562 Hz. The "Aug 23" upload (ksTWr449U2M) is just the first minute of the 11 Aug video.
External Quote:
Звук варьирует в диапазоне 93 - 562 Гц, основные 2 пика на 140 Гц и 211 Гц, также на 397 и 562 Гц.
(The sound varies over 93-562 Hz, the 2 main peaks are at 140 Hz and 211 Hz, also at 397 and 562 Hz.)
Source: the uploader's forum thread, 2012god.ru, 2011
http://2012god.ru/forum/forum-6/topic-1780/page-1/
It behaves like something working in cycles
About 5 s on, a new burst roughly every 10 s. The two main tones drift a few percent between bursts and not together, so it isn't a loop.
A school was being rushed next door
The video description gives Knyazhyi Zaton 17. The Kyiv Engineering Gymnasium, about 130 m away going by OpenStreetMap addresses, opened on 1 Sept 2011. KP Ukraine (27 Aug 2011) said a school there was being built "day and night" and that residents blamed an excavator bucket, though it adds that acousticians rejected that. Wind at the airport (12 km off) was light and from the N/NNW on both days, which is roughly school to camera.
External Quote:
Ведь на улице Княжий Затон, 10 (здесь снималось то самое видео), днем и ночью отстраивали школу, и якобы шумел металлический ковш экскаватора.
(After all, on Knyazhyi Zaton St, 10 (where that very video was filmed), a school was being built day and night, and supposedly a metal excavator bucket was making the noise.)
Source: KP Ukraine, 27 Aug 2011
https://kp.ua/kiev/298153-zhytelei-obolony-y-osokorkov-puhauit-ledeniaschye-krov-zvuky
What it isn't
No fog either afternoon per the airport reports; the murk is a 480x360 video on a grey day. And the white building with the green roof in the video is not the school.
Machines
I compared about 180 clips of site machines. Rollers, compactors and pavers give a steady locked drone, which this isn't. Closest were an excavator tearing out asphalt and dozer track squeal, but that's weak and I wouldn't name a machine from it.
Against
The filmer said the building work was a "mosquito's whine" next to the sound and that she saw only manual work nearby. An acoustician on Noviy Kanal put it down to wind resonating in an opening, and I can't rule that out. A NewsOne crew seems to have heard a similar sound from the next yard (about 2:00, going by the captions).
So: real sound, same source at least twice, most likely the works next door, machine unknown. If anyone knows Osokorky or can find a dated Aug 2011 satellite image, please shout.
Hope someone else can run further with this!
Sources:
School opening:
https://lb.ua/society/2011/09/01/112944_yanukovich_ne_vzyal_na_otkritie_shko.html
Local comments:
https://nevsedoma.com.ua/index.php?newsid=122426
NewsOne:
youtube.com/watch?v=7_o-p1IoWno
Noviy Kanal:
youtube.com/watch?v=SyXc3AnFa8s
Audio attached: 20 s, 3 Aug then 11 Aug.