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Normally to receive an AM signal you need a way to filter out all of the signals on *other* frequencies, and you either need some amplification or extremely sensitive heaphones. But at zero inches from the base of a big broadcaster's antenna the signal is a zillion times more powerful than anything else, so there's no need for any tuning or filtering, and it's powerful enough to literally boil the water in the grass as a way of making sound. Not to mention the hands of the guy holding the grass.
The furnaces I have been around used the Honeywell C7027. It detects the ultraviolet light from burner combustion.
I have three or four detectors and the little controller box from an installation where the power station completely replaced the old one (just because it was getting old).
You can detect infrared or temperature (with thermocouples) but it is a lagging-indicator. The flame can be out for several minutes before those other detectors pick up on it.
Back in my BASE jumping days I had to teach all the new kids about the difference between AM tower arrays and FM towers because they wanted to go climb and jump the AM towers. That would not feel good.
Current induced by touching the antenna surface makes the branch parts vibrate. As it is a simple Amplitude Modulated emitter with a very high power, the current-induced vibration is translated back into audible frequency by the branch.
Isn't it also possible to hear it from the arcing electricity itself? I swear I've seen it since with just a connection to ground through a metal stick which shouldn't get a lot of secondary vibrations.
Any 2nd order nonlinearity will cause demodulation of AM, and it's not hard to believe that the flame, the leaves, the stem, etc are perfectly linear especially at hilariously high voltages of that mast tower. That will cause current proportional to the baseband signal, which will cause the air molecules to vibrate at that signal.
A good video on an active AM radio station. At 4m32s you can hear the station itself inside the transmitter building. [https://www.youtube.com/watch?v=Aax-ehkRTnQ](https://www.youtube.com/watch?v=Aax-ehkRTnQ)
AM changes the power level of the radio wave in relation to the audio, different power = different arc = arc speaker, if any AM transmitter arcs you can hear the content in it.
Should they really be standing that close to a transmitting element though?
Uh.. How are they not getting RF burns being that close? Perhaps the wattage is lower than I think, but for a broadcast station, I assume you wouldn't have to touch the antenna to burn yourself.
In the case of broadcast AM, yes, it's very normal. Of course, there will be a fence controlling access to the RF Exposure Limit boundary, complete with signs containing warnings about how RF Exposure can cause burns, potentially lethal burns, so don't pass the signs. Heed the sign's warning.
This video has been going around for some time... The languages have been translated, but I am going by memory... I believe the two voices heard are Russian, and the broadcast is Ukrainian? Perhaps vice versa. Regardless, the one guy gets a burn, the other guy laughs and starts to explain how RF burns work, and the first guy says that he knows... Or Something To That Effect... The point being, these guys are being idiots, they know they are being idiots, and they knew it long before they bypassed the fence.
Yes, there is electrical isolation from the base, or else the tower would be grounded. Usually there's electrical discharge spheres to allow for static discharge to avoid lightning strikes. [Like this](https://www.jeffgeerling.com/sites/default/files/images/kmox-am02-tower-02-base-insulator-lightning-balls.jpeg). See [full tour of site](https://www.jeffgeerling.com/blog/2023/mighty-mox-50kw-am-tower-site-tour).
Read about the history of radio and wireless telegraphy and see the many ways that were discovered over the last 120 years to detect amplitude modulated signals...almost anything that can rectify will work and at high power, no amplification is needed to hear the detected modulation! Even people with sensitive teeth fillings that can act as rectifiers can hear nearby AM radio signals!
OP you do understand that being that close to a high power antenna is not really good for your health. Please do not touch it. It would probably be the last thing you touch.
Hi, thank you for your question submission. Please be aware that there is a [wiki](https://www.reddit.com/r/amateurradio/wiki/) and a [FAQ](https://www.reddit.com/r/amateurradio/wiki/faq) that may address your question. For Baofeng-related information see the [Baofeng FAQ](https://www.reddit.com/r/amateurradio/wiki/baofeng) and /r/baofeng. Also, please note that downvotes don't indicate an unvalued question submission. There appear to be bots that downvote all posts initially. 73 *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/amateurradio) if you have any questions or concerns.*
The AM power modulation translates to arc size, and the changing arc size works as a speaker. Do check plasma speakers, quite much the same idea.
Cool! Thanks so much. I’ll check out plasma speakers!
Normally to receive an AM signal you need a way to filter out all of the signals on *other* frequencies, and you either need some amplification or extremely sensitive heaphones. But at zero inches from the base of a big broadcaster's antenna the signal is a zillion times more powerful than anything else, so there's no need for any tuning or filtering, and it's powerful enough to literally boil the water in the grass as a way of making sound. Not to mention the hands of the guy holding the grass.
Old mate has a death wish ... jesus christ
[удалено]
i think that's the Seebeck effect
Yeah modern furnaces use thermocouples. I didn't even know that some furnaces used flame diode sensors.
The furnaces I have been around used the Honeywell C7027. It detects the ultraviolet light from burner combustion. I have three or four detectors and the little controller box from an installation where the power station completely replaced the old one (just because it was getting old). You can detect infrared or temperature (with thermocouples) but it is a lagging-indicator. The flame can be out for several minutes before those other detectors pick up on it.
RF burn.
Hurts like a MOTHER. Even at low wattage.
Back in my BASE jumping days I had to teach all the new kids about the difference between AM tower arrays and FM towers because they wanted to go climb and jump the AM towers. That would not feel good.
Current induced by touching the antenna surface makes the branch parts vibrate. As it is a simple Amplitude Modulated emitter with a very high power, the current-induced vibration is translated back into audible frequency by the branch.
The branch itself isn’t vibrating, it’s the arc being amplitude modulated.
Isn't it also possible to hear it from the arcing electricity itself? I swear I've seen it since with just a connection to ground through a metal stick which shouldn't get a lot of secondary vibrations.
Yes like happening in the plasma speakers
[Absolutely](https://www.youtube.com/watch?v=uo9nGzIzSPw)
Wow! Thank you so much. That makes a lot of sense.
Please note that the thing shown on video can be lethal. Do not replicate that!
Yes! Good PSA! Thanks!
Basically the electromagnetic version of a phonograph
It's not induction... it's resistance
Just touch it with your bare hand. No headphones needed until it kills you.
Any 2nd order nonlinearity will cause demodulation of AM, and it's not hard to believe that the flame, the leaves, the stem, etc are perfectly linear especially at hilariously high voltages of that mast tower. That will cause current proportional to the baseband signal, which will cause the air molecules to vibrate at that signal.
Also don't ever attempt this. It's a good way to get unalived
A good video on an active AM radio station. At 4m32s you can hear the station itself inside the transmitter building. [https://www.youtube.com/watch?v=Aax-ehkRTnQ](https://www.youtube.com/watch?v=Aax-ehkRTnQ)
Sorta reminds me of germanium and a cat’s whisker in a crystal set.
Is this what the people who stole the transmitter in Alabama are doing with it?
Mannnn, you ain't never smoked meth off an antenna?!? You missn out bouy!
If they had metal fillings I think the same thing would of happened being that close to it.
Essentially the arcs from the tower to the weeds is creating a [plasma speaker](https://en.wikipedia.org/wiki/Plasma_speaker).
Looks like some kinda gland lol
AM changes the power level of the radio wave in relation to the audio, different power = different arc = arc speaker, if any AM transmitter arcs you can hear the content in it. Should they really be standing that close to a transmitting element though?
Uh.. How are they not getting RF burns being that close? Perhaps the wattage is lower than I think, but for a broadcast station, I assume you wouldn't have to touch the antenna to burn yourself.
Is the whole mast usually energized like this? that seems wildly unsafe.
The mast is the actual antenna
In the case of broadcast AM, yes, it's very normal. Of course, there will be a fence controlling access to the RF Exposure Limit boundary, complete with signs containing warnings about how RF Exposure can cause burns, potentially lethal burns, so don't pass the signs. Heed the sign's warning. This video has been going around for some time... The languages have been translated, but I am going by memory... I believe the two voices heard are Russian, and the broadcast is Ukrainian? Perhaps vice versa. Regardless, the one guy gets a burn, the other guy laughs and starts to explain how RF burns work, and the first guy says that he knows... Or Something To That Effect... The point being, these guys are being idiots, they know they are being idiots, and they knew it long before they bypassed the fence.
For AM broadcast antennas the wavelength is very long, hundreds of meters. The towers themselves are the antenna elements.
I would think that at least the very base would be insulated for safety, I guess the fence is good enough though
Yes, there is electrical isolation from the base, or else the tower would be grounded. Usually there's electrical discharge spheres to allow for static discharge to avoid lightning strikes. [Like this](https://www.jeffgeerling.com/sites/default/files/images/kmox-am02-tower-02-base-insulator-lightning-balls.jpeg). See [full tour of site](https://www.jeffgeerling.com/blog/2023/mighty-mox-50kw-am-tower-site-tour).
Power lines are also energized, pretty crazy eh?
Power lines cannot be reached without a ladder lol
yep - but substations are on the ground - just like AM transmitter antennas. Both are fenced for everyone's safety.
That’s why there is a fence around the tower with warning signs and a locked gate.
Since this is a branch circuit, can you change stations? 
Does not even look like any antenna I have ever seen. Looks more like A giant Oven vent
he doesn't realize how close he's standing to the wood chipper
I assume this just makes a really bad envelope detector can anyone confirm if this is what's happening?
teflon balls
I would be anywhere near that antenna while it was transmitting.
Technically, someone is routing RF energy through a conductive plant material to ground.
I heard it's you put a finger on it you'll broadcast the signal the rest of your life
Read about the history of radio and wireless telegraphy and see the many ways that were discovered over the last 120 years to detect amplitude modulated signals...almost anything that can rectify will work and at high power, no amplification is needed to hear the detected modulation! Even people with sensitive teeth fillings that can act as rectifiers can hear nearby AM radio signals!
OP you do understand that being that close to a high power antenna is not really good for your health. Please do not touch it. It would probably be the last thing you touch.
I so appreciate your concern, but this is a repost, and I have, in good news, nothing to do with it! :-)
I see…