Why do some radio towers blink?

Regulations, NVG, and lighting types

• Commenters link FAA advisory material on obstruction marking/lighting and on LED/NVG compatibility.
• LED obstruction lights must include infrared output so they remain visible in night-vision goggles, unlike some visible-only LEDs.
• White strobes are typically used in daytime, red at night, and towers under ~200 ft generally don’t need lights (per the discussion).

Blog format and accessibility

• Several people find the article hard to read because it’s essentially a video transcript.
• Some prefer text anyway (can skim), others say transcripts make poor standalone posts.
• With JavaScript disabled, the embedded video is invisible, so readers may not realize it’s a transcript.

Synchronization of obstruction lights

• Nearby towers often blink out of sync, but wind farms and some clusters are synchronized.
• When intentional, this is usually done via GPS/GNSS time; FAA guidance prefers synchronization for some obstructions.
• Alternatives discussed: mains-frequency–derived timing, quartz/TCXO oscillators, atomic clocks, and theoretical grid-based resync schemes.
• Consensus: if you truly care about phase alignment between towers, you need a shared external time reference.

Wind farms, visibility, and ADLS

• Synchronized blinking across wind farms makes the entire farm appear as a single hazard, improving pilot awareness.
• Some find the effect awe-inspiring; others find it highly distracting and intrusive at night.
• FAA studies and rules are cited; radar-based Aircraft Detection Lighting Systems can keep lights off until aircraft are nearby, but are expensive.
• ADS‑B alone is considered insufficient for safety because many low-flying aircraft lack transponders.

Use of lights for navigation

• Obstruction lights double as navigation aids; charts document their color/patterns for position fixes.
• Comparisons are made to lighthouses, whose flash patterns and sectors are encoded on nautical charts and can be visually confusing near ports.

Three‑phase power, monitoring, and safety

• Anecdote: tower lights were distributed across three phases so the number of lit bulbs indicated phase loss from a distance.
• Some call this “best practice” for any three-phase user; others counter that the real best practice is automatic phase-monitoring relays that shut down motors on phase loss.
• Distributed lighting across phases also reduces stroboscopic hazards around rotating machinery.

Blinking, LEDs, power, and perception

• Blinking is noted to save power and, more importantly, to attract attention by introducing apparent motion.
• Discussion touches on PWM dimming, flicker fusion thresholds (~40 Hz and up), and people who are sensitive to LED flicker.
• Commenters reminisce about the slower, “glowing” incandescent beacons versus the sharper LED strobes now commonly used.

Geography and regulatory differences

• Some regions (e.g., parts of Norway) seemingly have fewer blinking towers, but local regulations do require “hinderlys” above certain heights (15–30 m) with red or white blinking lights.
• One comment notes that in principle minimum safe altitudes reduce the need for lights, but “see and avoid” rules still drive their use.

Maintenance and tower work

• Tower maintenance often involves protective suits, especially for old lead-painted structures (Tyvek-style, not ghillie suits, despite a humorous slip).
• A linked video of changing tower bulbs illustrates how physically demanding and risky the work is.

Meta reactions and side notes

• Some readers say the article’s narrative is pleasant but the conclusions feel obvious.
• Others mention related, more engaging posts by the same author.
• There are mentions of NOTAM automation when tower lights fail, and of AI being able to summarize such verbose posts quickly.