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Posted: 4/23/2019 2:19:22 PM EDT
[#1]
Quoted:
What is the radiation output under a cell tower compared to background radiation? I've seen some devices where they climb right past them and some where they want the signal output shut off before a climber starts to climb the tower. I think the big point to point radios are the worst as compared to a multi-point sector or omni. |
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Posted: 4/23/2019 2:36:07 PM EDT
[#2]
Quoted:
What is the radiation output under a cell tower compared to background radiation? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? |
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Posted: 4/23/2019 4:22:03 PM EDT
[#3]
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Posted: 4/24/2019 1:08:22 AM EDT
[#4]
Quote HistoryQuoted: What do you mean by "radiation output"? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? |
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Posted: 4/24/2019 1:09:54 AM EDT
[#5]
Quote HistoryQuoted:
Novice question. I didn't even sleep at a holiday inn. A typical urban area cell tower. Would you want to work in the office right at the bottom of the tower everyday for years...? Quote HistoryQuoted:
Quoted: What do you mean by "radiation output"? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? Great signal that way! |
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Posted: 4/24/2019 1:43:57 AM EDT
[#6]
Quote HistoryQuoted: Novice question. I didn't even sleep at a holiday inn. A typical urban area cell tower. Would you want to work in the office right at the bottom of the tower everyday for years...? |
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Posted: 4/25/2019 12:40:00 PM EDT
[#7]
Quote HistoryQuoted:
I'd love to. Great signal that way! Quote HistoryQuoted:
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Quoted: What do you mean by "radiation output"? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? Great signal that way! It may still be strong enough at that short distance for decent communication though. They are optimized for a horizontal radiation pattern. |
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Posted: 4/25/2019 12:46:10 PM EDT
[#8]
Quote HistoryQuoted:
For the most part you would actually be in antenna nulls. It may still be strong enough at that short distance for decent communication though. They are optimized for a horizontal radiation pattern. Quote HistoryQuoted:
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Quoted: What do you mean by "radiation output"? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? Great signal that way! It may still be strong enough at that short distance for decent communication though. They are optimized for a horizontal radiation pattern. 
So we'll use out imaginations.
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Posted: 4/26/2019 11:31:14 AM EDT
[#9]
Quote HistoryQuoted:
I think for the sake of this conversation, OP is asking about you being in the path of the bulk of the radiation.
So we'll use out imaginations. Quote HistoryQuoted:
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Quoted: What do you mean by "radiation output"? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? Great signal that way! It may still be strong enough at that short distance for decent communication though. They are optimized for a horizontal radiation pattern.
So we'll use out imaginations. It is optimized for distance. And at the higher frequencies (shorter wavelengths (3e8 / f = wavelength length in meters)) you are likely be far field conditions (>10 wavelengths) anywhere on the ground. And coupled energy is a strong function of wavelength, your apparent impedance, and you physical size. |
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Posted: 4/26/2019 11:36:04 AM EDT
[#10]
Quote HistoryQuoted:
That is not how the antenna pattern is set up. It is optimized for distance. And at the higher frequencies (shorter wavelengths (3e8 / f = wavelength length in meters)) you are likely be far field conditions (<10 wavelengths) anywhere on the ground. And coupled energy is a strong function of wavelength, your apparent impedance, and you physical size. Quote HistoryQuoted:
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Quoted: What do you mean by "radiation output"? And what do you mean by "background radiation"? RF? Ionizing radiation? Something else? Great signal that way! It may still be strong enough at that short distance for decent communication though. They are optimized for a horizontal radiation pattern.
So we'll use out imaginations. It is optimized for distance. And at the higher frequencies (shorter wavelengths (3e8 / f = wavelength length in meters)) you are likely be far field conditions (<10 wavelengths) anywhere on the ground. And coupled energy is a strong function of wavelength, your apparent impedance, and you physical size. 
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Posted: 4/26/2019 11:39:36 AM EDT
[#11]
Quote HistoryQuoted:
I'm no expert, but it would all depend on what gear is being used, what freq and power level. I've seen some devices where they climb right past them and some where they want the signal output shut off before a climber starts to climb the tower. I think the big point to point radios are the worst as compared to a multi-point sector or omni. |
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Posted: 4/26/2019 11:52:33 AM EDT
[#12]
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Posted: 4/26/2019 12:31:27 PM EDT
[#13]
Quote HistoryMaybe I'm mistaken, but I understood OP's question as "would you be willing to sit in front of a cell phone tower output all day"... not literally at the base of the antenna.
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Posted: 4/26/2019 12:41:55 PM EDT
[#14]
Quote HistoryQuoted: I get that. Maybe I'm mistaken, but I understood OP's question as "would you be willing to sit in front of a cell phone tower output all day"... not literally at the base of the antenna. Even with amateur radio equipment you need to consider how much RF exposure your taking in. Sitting in front of a high wattage output from a commercial, directional antenna will certainly push you over the safe exposure range. Just touching the antenna will probably give you RF burn. Maybe even just sitting in front of it. http://www.arrl.org/rf-exposure Interesting info from a cell tower worker/climber https://www.cracked.com/personal-experiences-2308-5-terrifying-realities-my-job-as-cell-tower-climber.html |
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Posted: 4/26/2019 3:03:10 PM EDT
[#15]
There are real reasons that many ships have all sorts of RF hazard markings on various decks.
I have been near a restricted area and you could feel your skin crawl. Spread your arms and it was noticeably worse. We had RF monitors and alarms in a number of our labs. We had an attenuator fail once on a many thousand watt radar being characterized. Captured equipment. After that we set up a system that would kill prime power when the alarms went off. |
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Posted: 5/6/2019 10:27:38 AM EDT
[#16]
FCC has specific guidelines for RF exposure.
You probably are exposed to higher power from your own cell phone than any emission from a cell phone tower. Cell phone towers are high and have a very narrow signal that is not directed at the ground under the tower. RF radiation is not ionizing and only heats up tissue but does no other damage. |
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Posted: 5/15/2019 11:37:39 PM EDT
[#17]
From my quick search which may be incorrect, a cell tower outputs 100w for city towers and up to 500w rural. With electromagnetic radiation following the inverse square law, you probably are getting way more EM exposure from the cell phone in your pocket or the computer at your desk than the cell tower.
And as was stated the antennas aren't optimized for vertical transmission so even less. It wouldn't surprise me if standing under the tower and you have a signal it is bounced off a natural reflector or even more likely on a totally different tower. |
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Posted: 12/26/2020 7:56:36 PM EDT
[#18]
Quote HistoryQuoted: From my quick search which may be incorrect, a cell tower outputs 100w for city towers and up to 500w rural. With electromagnetic radiation following the inverse square law, you probably are getting way more EM exposure from the cell phone in your pocket or the computer at your desk than the cell tower. And as was stated the antennas aren't optimized for vertical transmission so even less. It wouldn't surprise me if standing under the tower and you have a signal it is bounced off a natural reflector or even more likely on a totally different tower. The distance is small directly under the tower, and may well be in near field conditions depending on actual wavelength. We had a comms system on a U-2. At a nominal 60,000 ft from the top of the fuselage the signal strength of a blade (AT256A, IIRC) antenna in UHF (225 MHz to 500 Mhz) was more than adequate for 1E-6 BER directly under the plane using 4-ary digital FSK modulation at 32kBaud/s in 25 kHz BW. The problem is that indirect (reflected) paths also existed from signal reflection off the large 'super pods) used to contain the SIGINT system. We provided real time system SIGINT EW results to ground terminals directly under the plane. The modelling was an absolute nightmare. |
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Posted: 12/27/2020 6:35:08 PM EDT
[#19]
holy necro post. how is this not archived?
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Posted: 1/4/2021 1:03:56 AM EDT
[#20]
Quote HistoryQuoted: holy necro post. how is this not archived? Lol, it's brickeye... a bored, retired guy that likes to passively brag about his past any way he can! |
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Posted: 1/4/2021 1:27:57 AM EDT
[#21]
Quote HistoryQuoted: holy necro post. how is this not archived? Apparently forums maintain a minimum thread count. If the minimum is set at 100 the most recent 100 threads will continue to live until they are pushed into the archive by newer threads. |
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Posted: 1/6/2021 1:31:50 PM EDT
[#22]
Quote HistoryQuoted: Lol, it's brickeye... a bored, retired guy that likes to passively brag about his past any way he can! Quote HistoryQuoted: Quoted: holy necro post. how is this not archived? Lol, it's brickeye... a bored, retired guy that likes to passively brag about his past any way he can! I would suggest you pound sand. |
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Posted: 1/13/2021 11:31:01 PM EDT
[#23]
Considering the size of the antenna array compared to the frequencies used, an ERP of 100 watts can be achieved with less than 5 watts of power to the feedpoint. The point is that the antenna gain is very great to pull in 0.6 watt handset transmitters better known as cell phones.
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Posted: 1/17/2021 9:15:48 PM EDT
[#24]
Quote HistoryQuoted: Considering the size of the antenna array compared to the frequencies used, an ERP of 100 watts can be achieved with less than 5 watts of power to the feedpoint. The point is that the antenna gain is very great to pull in 0.6 watt handset transmitters better known as cell phones. You probably mean EIRP. Equivalent Isotropic Radiated Power. |
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Posted: 2/15/2021 2:06:09 PM EDT
[#25]
The question is not asked correctly.
But, signal to noise ratio under a tower is high. Power density is rated power in a shape field, like omni donut vs yagi vs corner reflected vs others, etc. Exceeding power density limits is ez to do even when your max rated output power is less than a max allowed #. |
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Posted: 2/18/2021 2:04:51 PM EDT
[#26]
That close to the antenna is likely not in far field conditions.
Far field is generally not established until you are more than 10 wavelengths from the antenna. And depending on the directivity and shaping of the beam it can be closer to 20 to 30 wavelengths. |
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Posted: 4/5/2021 11:33:35 PM EDT
[#27]
EIRP or ERP whatever. Since the tower owners don't have a crew sweeping piles of dead birds from the tower bases, you will be alright from the radiation.
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Posted: 4/5/2021 11:39:31 PM EDT
[#28]
Quote HistoryQuoted: FCC has specific guidelines for RF exposure. You probably are exposed to higher power from your own cell phone than any emission from a cell phone tower. Cell phone towers are high and have a very narrow signal that is not directed at the ground under the tower. RF radiation is not ionizing and only heats up tissue but does no other damage.  Attached File |
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Posted: 5/11/2021 1:29:44 PM EDT
[#29]
Quote HistoryQuoted: FCC has specific guidelines for RF exposure. You probably are exposed to higher power from your own cell phone than any emission from a cell phone tower. Cell phone towers are high and have a very narrow signal that is not directed at the ground under the tower. RF radiation is not ionizing and only heats up tissue but does no other damage. Strong enough fields at the right frequency can interfere with nerve function, or produce felt things that are not real. The feeling of intense heat is one of these 'tricks.' It is NOT from actual heating, but by interfering with sensory nerves. |
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Posted: 7/18/2021 11:38:04 AM EDT
[#30]
femtowatts and picowatts. You can dl a cellular signal measurement app on your phone. The output from your phone on the desk is orders of magnitude higher.
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Posted: 7/19/2021 5:57:52 AM EDT
[#31]
So the radiation radiates out from the top of the tower not down.
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Posted: 7/19/2021 8:46:13 AM EDT
[#32]
What does that mean?
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Posted: 8/16/2021 3:27:42 PM EDT
[#33]
Quote HistoryQuoted: So the radiation radiates out from the top of the tower not down. It is 'aimed' sideways from the elements at the top of the tower. |
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