I’m not very knowledgable about the science of broadcasting radio signals. I assume that the transmitting gizmo at the top of a commercial radio tower is broadcasting very powerful radio waves. So, if I stood next to it for a few seconds (or a few minutes), what would happen? Instand death? Excruciating pain? Absolutely nothing?
NOTE: I wrote, and tried to post, this exact thread just a few minutes ago, and then my computer went all wonky. So I apologize in advance if this is double-posted.
It is likely that the chocolate bar in your pocket will melt.
Other than that, the guy with the banana on his head may shoot you in the back with a laser capable of emitting a beam of pure anti-matter. But that’s it.
Back when I was young and stupid, a friend and I climbed to the top of a 300’ telephone microwave relay tower, and stayed on top for about five minutes or so without any ill effect.
Just to show how young and stupid I was in those days, when I climbed down I climbed down the OUTSIDE of the tower, rather than the ladder in the center of it.
Sheesh. I ever catch MY kid pulling something that dumb…
Probably not much.
Radio waves can be very harmful. After all, that’s what your microwave oven uses to cook food. Fortunately, the frequencies that FM radio and broadcast television use (for example) don’t get absorbed as much by the water and tissues in your body as do the frequencies that a microwave oven operates on. A radar set would do a lot more damage as an FM radio station operating on the exact same power level.
The other thing in your favor is that the radio waves spread out in all directions, which means that the amount of radio waves your body receives drops off proportionally to the square of the distance you are away from the antenna. You only get 1/4th the radio waves when you are 2 feet away from the antenna as you would if you were 1 foot away. Move 3 feet away and you only get 1/9th as much exposure, and so on.
If the radio transmitter in question was powerful enough, and you got close enough to the antenna (you might have to be almost touching it) then you could end up with an RF burn, which would be the antenna cooking you pretty much the same way that a microwave oven cooks food. The radio waves cause the molecules in your body to vibrate and make heat, which burns you. The difference between this and a normal burn is that the heat is generated from inside you, so you don’t get any warning from the nerves in your skin heating up. By the time you feel pain, you’ve already got a really nasty burn, and it goes deep into your body tissues.
Simple: You would be arrested. 
The FCC has exposure limits for RF signals. I can’t make a gret deal of sense of the document, but it does mention that
so there are limits. You would probably be OK for a few minutes, but it would be best not to camp up there for more than a couple of days.
If it doesn’t jostle your proteins enough to cause an RF burn, it might damage your genes enough to give you a higher risk of cancer later on (decades down the line, even). But that’s a rather distant possibility, and probably not worth worrying about for one or two brief exposures.
I wonder what the cancer rate of the radio technicians who climb live towers is, as compared to the national averages. (It might be interesting to focus on tower-climbers versus airline pilots, to correct for the effects of cosmic rays.)
Quoting my husband, the Chief Engineer: If it’s got a gizmo at the top, it’s an FM tower. A lot would depend on the power.
But basically, you’d be slowly cooked. The damage would start with your eyes and your balls (if you come equipped with those).
So if you’re planning on climbing up one of those towers–find something else to do.
Technically, that’s only true if you’re farther away from the antenna than the size of the antenna itself. Electromagnetic waves simply aren’t capable of varying much in intensity over a scale less than their wavelength. Closer in, the strength should be roughly constant, so being right next to a radio wave source is less dangerous than you might otherwise think (which is not to say it isn’t dangerous at all).
I wouldn’t expect anything serious, though I’d be wary since I’d guess, what with larger areas to cover, that US transmitters are more powerful than their UK equivalents.
Early warning radars are another matter - they often do have boundaries around the antenna where you’re not meant to walk to prevent health risks.
I remember seeing a picture, I think in an issue of Natl. Geographic, of an outstretched hand holding a glowing fluorescent bulb in mid-air. The bulb was being held by a man on the ground, who was standing beneath an enormous Cuban radio tower used to jam radio broadcasts from the US.
I wonder how quickly that sucker would toast your eyeballs while you were climbing it.
I’d think that’s a prerequisite for climbing a radio tower.
Radio waves are non-ionizing radiation, the same as infra-red and visible light. Exposure to radio waves, as far as our present understanding of them goes, is no more harmful than exposure to the light from a flashlight. Sure you can get burned from RF, but you can get burned from visible light too (ask anyone who ever fried an ant with a magnifying glass).
Electromagnetic radiation doesn’t become ionizing until it gets up into the ultraviolet light range. At these frequencies and above, the electromagnetic wave can strip the electrons off of atoms and create ions (hence it is called ionizing radiation), which is known to cause cell damage and cancer.
I’ve seen a few studies which reported to show a link between being a radio technician and cancers, but these are generally in the same boat as studies linking cell phones and cancer, and power lines and cancer. The studies are often contradictory with other studies and don’t hold up after follow-ups have been done. Unfortunately, it’s a murky subject with people on both sides of the fence who are convinced they are right and are both very passionate about their views, so it’s almost impossible to find an unbiased source on the subject, and with so many contradictory studies out there it is difficult for people who do have a good understanding of the topic to sort through it all. So far, though, a clear link between working with radio waves and cancer has not been established.
Radio towers aren’t tall enough to worry about increased exposure to cosmic rays.
Brief aside. I understand that even if you are broadcasting 1000 watts out of that sucker, it isn’t enough to cook you any time fast with just the microwaves.
But, IIRC, when I was 14-16 and did ham radio, we were worried about RF burns from a 10m dipole antenna that my friend and I made. That was only around 100 watts (at 10m and 20m, where we did most of the voice stuff, we general licenses). Were we being paranoid or was there something else going on here? Could a radio antenna cause enough voltage shift in metallic objects on your person to cause a burn?
Some months ago I saw a documentary about base jumping, much of it was filmed on a huge radio and TV antena somewehere in Australia. Now that thing was enormous, well over 300 meters high IIRC, the jumpers said over and over again how they were not supposed to stay on the top for more than 5 minutes or so to prevent damage from the RF signal. However since the fellows base-jumped in duos and triples and with double deployments of parachutes (main, cut, reserve then) you should take their risk assesment capacities with a grain of salt. 
I’ve been told that excessive RF exposure can result in cataracts, due to the eye’s limited ability to dissipate heat.
Really high power levels can cause death or serious injury. I’ve heard many stories about birds being killed by high-power radar systems when the radar was configured to track the bird.
This thread is of interest to me as when I was at universoty in Sheffield I lived in a house which had a radio tower practically in the back yard - it was perhaps 25 metres from the back door. I lived there for a year - should I be worried?
[sub](No wonder the rent was so cheap)[/sub]
I just had a search for it on the web to see if I could find what the tower actually was - it’s here. The photo about halfway down the page shows how close it is to the houses. It’s a combined TV and radio transmitter. On the plus side, I got great TV reception - I didn’t even need an aerial on my portable TV, I just wedged a pair of nail scissors in the aerial socket…
For a while I lived on a hill in London with line of sight about a mile to the Crystal Palace Tower. My TV aerial was a half straightened paperclip. There’s a road that passes right by the base of the tower and boy all the RF does weird things to the car radio. Possibly people living close by don’t even need to switch their TVs on.
Well, they might be able to hear the signal through their fillings, but no-one broadcasts a signal strong enough (or in a suitable format) to appear on an unpowered TV set.
AM audio is easy to “decode” - I used to make receivers out of a razor blade, thumbtacks and a paperclip that would receive a signal, audible through headphones. But television involves a lot more in the way of interpretation by the set’s electronics, and they have to be powered up and working according to specifications in order to do their job.