Sydney skyline (and synchronised aircraft obstruction lighting)

[Halcyon]

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).

[tom66]

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!

[Ed.Kloonk]

These aren't the red lights in Sydney you're looking for.

[Halcyon]

These aren't the red lights in Sydney you're looking for.

You're quite wrong. Those are the *only* red lights I'm looking for ;-)

[pcprogrammer]

These aren't the red lights in Sydney you're looking for.

Now it is official, you sir have a very very dirty mind

[Brumby]

These aren't the red lights in Sydney you're looking for.

Now it is official, you sir have a very very dirty mind

Oh? ..... OOHHHHHHH.

Sorry - it took me a minute to catch on.  I have to agree with pcprogrammer.

[james_s]

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.

[Halcyon]

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.

I'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?

[mikeselectricstuff]

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 ago
https://www.kickstarter.com/projects/966222131/straightedge-a-new-way-to-see-your-planet/description

[EEVblog]

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?

[EEVblog]

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.

I'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?

I think it would be so they aren't lost in a sea of other random blinky lights.

[EEVblog]

Just tried to google it and this thread popped up as #3 !

[Halcyon]

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?

I can hook you up with an on-location shoot. BYO camera.

[EEVblog]

FAA requirements:
https://www.faa.gov/documentlibrary/media/advisory_circular/ac_70_7460-1l_.pdf
Advised for catenary.
Compulsary sync for wind turbines to within 0.05sec, section 13.5.3

Australia: https://www.casa.gov.au/node/55134

[Halcyon]

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?

[mikeselectricstuff]

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.

[Brumby]

Might even have some contacts in the field to get you up on top for some close-up shots?

[EEVblog]

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.

[Ed.Kloonk]

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.

There should be some around the hospital.

[EEVblog]

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.

There should be some around the hospital.

I might take a drive around tomorrow night and also go rooftopping.

[Brumby]

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)

[themadhippy]

I might take a drive around tomorrow night

Aint 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

[james_s]

I might take a drive around tomorrow night

Aint 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

The 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.