Sydney skyline (and synchronised aircraft obstruction lighting) - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: August 22, 2022, 10:40:45 am
content: I've been staying in Sydney city the past week for work and something interesting caught my attention. On the tops of a few buildings are those red flashing beacons to warn aircraft, but they are perfectly synchronised, despite the buildings being quite some distance apart. Looking into it some more, some brands apparently sync the flashes to a GPS clock. So you could have 2 or 200 of these lights and they will all flash at the same interval and remain in sync with each other.Seems trivial but fascinating at the same time.(And for those interested, attached is a photo. I apologise for the crudity, my phone sucks).

author: tom66
author_rank: Super Contributor
timestamp: August 22, 2022, 10:57:18 am
content: That's quite interesting. There are some airports where the landing lights are mounted on nearby apartment blocks, industrial units, etc. such as Innsbruck, Austria:https://www.google.com/maps/place/Innsbruck,+Austria/@47.2636129,11.3565121,2755m/data=!3m1!1e3!4m5!3m4!1s0x479d6ecfe1f8ca73:0x9d201c7d281d9b0d!8m2!3d47.2692124!4d11.4041024...which is an extremely difficult airport to land at!

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: August 22, 2022, 11:47:07 am
content: These aren't the red lights in Sydney you're looking for.

author: Halcyon
author_rank: Unknown
timestamp: August 22, 2022, 12:06:04 pm
content: Quote from: Ed.Kloonk on August 22, 2022, 11:47:07 amYou're quite wrong. Those are the *only* red lights I'm looking for ;-)

author: pcprogrammer
author_rank: Super Contributor
timestamp: August 22, 2022, 12:21:36 pm
content: Quote from: Ed.Kloonk on August 22, 2022, 11:47:07 amNow it is official, you sir have a very very dirty mind

author: Brumby
author_rank: Unknown
timestamp: August 23, 2022, 05:54:23 am
content: Quote from: pcprogrammer on August 22, 2022, 12:21:36 pmOh? ..... OOHHHHHHH.Sorry - it took me a minute to catch on. I have to agree with pcprogrammer.

author: james_s
author_rank: Super Contributor
timestamp: August 23, 2022, 07:12:13 am
content: Many of the flasher units for marine navigation buoys have an option of using a GPS receiver for synchronization. I noticed the same thing with the obstruction lights on the wind turbines in Eastern Washington. I'm not actually sure why they synchronize them, it seems that random flashing would be more eye catching.

author: Halcyon
author_rank: Unknown
timestamp: August 23, 2022, 07:17:43 am
content: Quote from: james_s on August 23, 2022, 07:12:13 amI'm sure there is a reason for it. Perhaps having a series of lights flashing at once allows the pilot to paint an invisible line linking them together in his mind. I really don't know... any pilots here?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 23, 2022, 08:34:01 am
content: It's not about being eye catching, but identification. Having them synced makes them stand out from all the other random light sources in a city. With a single distant point, it's almost impossible to judge distance and hence height. A single flashing light could be anything, but being synced means they are clearly identifiable as lights on top of tall structures.Reminds me of this kickstarter art project from many years agohttps://www.kickstarter.com/projects/966222131/straightedge-a-new-way-to-see-your-planet/description

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2022, 09:32:06 am
content: That's Tom Scott level video interesting.I have been looking for content again for my EEVdiscover channel.I wonder who would be the expert on this stuff?

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2022, 09:33:08 am
content: Quote from: Halcyon on August 23, 2022, 07:17:43 amI think it would be so they aren't lost in a sea of other random blinky lights.

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2022, 09:34:18 am
content: Just tried to google it and this thread popped up as #3 !

author: Halcyon
author_rank: Unknown
timestamp: August 23, 2022, 09:34:35 am
content: Quote from: EEVblog on August 23, 2022, 09:32:06 amI can hook you up with an on-location shoot. BYO camera.

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2022, 10:05:27 am
content: FAA requirements:https://www.faa.gov/documentlibrary/media/advisory_circular/ac_70_7460-1l_.pdfAdvised for catenary.Compulsary sync for wind turbines to within 0.05sec, section 13.5.3Australia:https://www.casa.gov.au/node/55134

author: Halcyon
author_rank: Unknown
timestamp: August 23, 2022, 10:25:46 am
content: if you're interested in a video Dave, flick me an email. I actually know someone in the "crane" business who would be happy to talk to you. Might even have some contacts in the field to get you up on top for some close-up shots?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 23, 2022, 11:11:59 am
content: in London, red lights started sprouting from buildings after a helicopter crash a few years ago. Not flashing though - would look pretty cool, as there are places approaching the city where almost the whole horizon is a sea of red dots.

author: Brumby
author_rank: Unknown
timestamp: August 23, 2022, 11:26:44 am
content: Quote from: Halcyon on August 23, 2022, 10:25:46 am

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2022, 12:14:33 pm
content: I wonder if they have any of these in my local Norwest, can't say I've ever noticed. I think the tallest building is 12 stories or something, so probbaly not.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: August 23, 2022, 12:16:22 pm
content: Quote from: EEVblog on August 23, 2022, 12:14:33 pmThere should be some around the hospital.

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2022, 12:21:49 pm
content: Quote from: Ed.Kloonk on August 23, 2022, 12:16:22 pmI might take a drive around tomorrow night and also go rooftopping.

author: Brumby
author_rank: Unknown
timestamp: August 23, 2022, 12:37:36 pm
content: There are some around Parramatta and Westmead Hospital. Maybe check out the top of Oakes Rd, Winston Hills or further along on Buckleys Road (near the corner of Langdon Rd)

author: themadhippy
author_rank: Super Contributor
timestamp: August 23, 2022, 01:41:10 pm
content: QuoteAint driving around looking for red lights also known as curb crawling?Ok beings serious, wonder why they dont make them flash a code to give a location,like lighthouses

author: james_s
author_rank: Super Contributor
timestamp: August 23, 2022, 04:50:57 pm
content: Quote from: themadhippy on August 23, 2022, 01:41:10 pmThe marine beacons I mentioned earlier do, there are ~240 different flash patterns defined by the IALA, if you look on a nautical chart the lights will be shown with their associated patterns. In the case of obstruction beacons I suspect it's because they are not intended for navigation, the are to indicate an obstruction.