Truly, thank you so much for responding. I love learning from experts.
This is usually combined with a very well insulated cage to prevent that energy from escaping
Faraday cage. Please. I’m a fool, not an imbecile. And to be clear, I’m well-aware of ionizing radiation bands.
However, my concerns lie in extended exposure. I’ll relate this to analog. Regardless of frequency, sound as quiet as 70 decibels can cause hearing loss after extended exposure. In the territory of 24 hours and longer, mind you. This is as quiet as, say, a hearty conversation, or a washing machine.
And this is a dual inverted sliding scale. Hearing loss zones:
- | XXdB | Duration before hearing loss. |
- | 70dB | 24h | As quiet as a clothes washer can cause hearing loss. Really.
- | 75dB | 8h |
- | 80dB | 2h |
- | 90dB | 1h |
- | 95dB | 50m |
- | 100dB | 15m |
- | 105dB | <5m |
- | 110dB | <2m |
- | 120+dB | Instantaneous |
I’d like to know where the scales for EM radiation amplitudes are. I’ve read a few studies but most of them focus on bursts or separated exposures. Very few of them observe sustained continuous exposure.
Also, I’m aware sound and radiation are not apples to apples, but my point of relating energy input and exposure duration is the same. If you ask anyone if 70 dB is safe, everyone will tell you, “Yes. Of course.” Which is not correct. Even 60 dB can do you further harm, if your ears have not healed from damage sustained immediately prior.
Some small levels of UV 3 might get through (hello skin cancer).
Now you’re getting into much more familiar territory. UV-A, the lowest band of UV, at UV 1 is entirely capable of causing sun-burns. It just depends on exposure time and pigmentation. Any sunburn has the potential to cause cancer. The more intense the burn and larger the affected area, the higher the chance more cells mutate, the higher your chance one of those cells becomes an unstable cancer cell, the higher the chance one of those cells becomes stable, and the higher chance for metastasis… From non-ionising low flux UV-A. Possible, but unlikely. Though increasingly likely as duration increases.
These transmitters can be legally and safely placed in urban areas provided adequate separation between the antenna and the public, usually 30-40 meters.
The EIRP drops off quickly in the first few meters after the antenna, as the signal expands outwards towards the service area; so even being within 15m is generally safe.
Inverse square, I’m familiar. And now we’re cooking with fire. Let’s elide frequency for a moment, pretending it’s irrelevant in the same way mechanical waves’ frequencies are.
Let’s assume 30-40 meters for 100KW antenna and 15 meters for ~20W macro cell is instantaneous minor damage. With each meter you distance yourself, the concentration of wattage decreases. What do you suppose the limit of energy density is for immediate damage when in direct contact? What do you suppose is the limit of wattage for sustained direct exposure on scale of 24 hours. That is, the equivalent of 70dB for intensity. What about sustained exposure for several years?
I don’t fear the effects it will have. After all, death will come to us all at some point. However, that doesn’t mean I’ll be reckless with the time I have left.
Also, I just started studying to get my Ham and haven’t quite wrapped my brain around a lot of the implications, so your input is very much appreciated. Thanks.
