Cell tower flashing beacons

[J Route Z]

Does anyone know the FAA guidelines per flashing lights on top of communications towers? I'm seeing more LED bulbs that flash red at night very quickly, maybe about a half of a second with 5 seconds between flashes. These lights used to have a more slower fade in fade out type of flash, with 1 second between flashes. These also have white daytime beacons which flash just as fast as the night time ones. Although some red beacons I've seen flash 2-3 seconds long.

[Pink Jazz]

Does anyone know the FAA guidelines per flashing lights on top of communications towers? I'm seeing more LED bulbs that flash red at night very quickly, maybe about a half of a second with 5 seconds between flashes. These lights used to have a more slower fade in fade out type of flash, with 1 second between flashes. These also have white daytime beacons which flash just as fast as the night time ones. Although some red beacons I've seen flash 2-3 seconds long.

Historically, the red night lights were a slow flashing halogen light, while the white daytime strobes were a bright xenon flasher.  The red night lights were the first to be switched over to LED technology.  More recently the white daytime strobes are now being switched to LED technology as well.

[hbelkins]

Is there a reason that the white strobes can't be used at night as well as during the day?

[SectorZ]

Is there a reason that the white strobes can't be used at night as well as during the day?

The white can cause a temporary blinding effect at night, where as during the day it is not as likely to. So, the softer red gets used at night, since the lights are only "be seen" lights, as opposed to lights that need to help something see (like headlights).

[-- US 175 --]

Several of the non-radio/TV towers in the Dallas area, that I've seen, use white strobes at night.  99% of the time, the big radio/TV towers at Cedar Hill use red lights at night; I'm not sure which of them have gone onto LED yet and which ones have not.  At least 2 of the TV towers in east TX use white strobes all the time.  Was a little different getting used to that after only seeing towers with the red lights there before.

[DaBigE]

Several of the non-radio/TV towers in the Dallas area, that I've seen, use white strobes at night.  99% of the time, the big radio/TV towers at Cedar Hill use red lights at night; I'm not sure which of them have gone onto LED yet and which ones have not.  At least 2 of the TV towers in east TX use white strobes all the time.  Was a little different getting used to that after only seeing towers with the red lights there before.

I can see one out my window here that flashes white day and night. The difference is the length of the 'on' period. During the day, it's a quick, strobe flash. At night, it's a slightly slower flash (1-second on?).

Conversely, there's a couple extremely tall towers in Madison which flash white during the day, then switch to red at night. I remember seeing the switchover a couple evenings from my apartment window back in college.

[Pink Jazz]

Also, the white strobe can act as a backup at night if the red light fails.