KNBR (AM 680) Antennas, Redwood City, CA, 2024.
All the pixels, none of the RF exposure, at https://www.flickr.com/photos/mattblaze/54131419266
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this post was submitted on 21 Jan 2025
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Note, important safety tip: you can get closer to this tower without clearly trespassing or jumping fences than most other 50KW broadcast antennas I've encountered. I measured a field strength of over 80V/m a bit outside the tower fence, which is an incredibly strong signal (though still within OSHA limits at the frequency involved).
Resist any temptation to jump the fence and climb the (energized) tower. You'd be electrocuted as soon as you touch it.
@[email protected] Interesting I'm going to do some field tests for interference for a wildlife monitoring radio system & I'm wondering what you used to measure this
@mwhelm For AM, the instruments of choice are the Potomac FIM-41 or PI-4100 (the former being older, analog, and more fun to use, the latter being soulless, digital, and easier to use).
@[email protected]
@[email protected] there may be a literal pair of smoking boots as the only remaining evidence.
@greem @mattblaze I’ve seen that movie.
@20002ist @greem I don't think you want to look in the trunk, officer...
@[email protected] @[email protected] The actual line is even better.
@[email protected] @[email protected] Proof that "You don't want to look in there" > "I do not consent to a search"
@[email protected] @[email protected] @[email protected] I’m gleeful to see the absolute best film ever made finally referenced here. Laughing aloud, thanks
@[email protected]
Ever since I saw this video by @[email protected], I realized that respect for towers could be life-saving.
https://youtu.be/GgDxXDV4_hc
@mattblaze
To your point:
https://www.youtube.com/watch?v=GgDxXDV4%5C_hc
@HikerGeek @mattblaze
Wow. 😎 I was a radio DJ for a couple years but did *not* know this. Is it same for AM and FM?
@ColesStreetPothole @HikerGeek No; FM broadcast antennas are comparatively quite small. The tower structures for them are just to get them up high and should not themselves be energized with RF. But the RF fields near the antennas can reach dangerous levels. (You can't go to the roof of the World Trade Center, which hosts a bunch of FM and TV stations, without special precautions, for example).
@[email protected] @[email protected] Ah, okay. I was an FM jockey, but we never got to see the tower, it was miles away.
@HikerGeek @mattblaze Jeff Geerling can be pretty funny.
How are such towers climbed safely if a technician is needed?
@JamieGC @HikerGeek You turn the transmitter off first.
@[email protected] @[email protected] that should have been obvious I suppose. 🙂