Large HF transmitter 200kw  AN/FRT-62   and health effects - Page 1
Forum section: electronics / general

author: ez24
author_rank: Super Contributor
timestamp: September 15, 2015, 09:56:05 am
content: When the high power switch tripped the building would shake. This was in 1970 and I cannot even remember where the switch was. Working on this was my entire Navy career and no pictures. Mine was at a different location and I think we had 6 of these but lots of smaller ones (40kw). Ours covered the Indian Ocean from Eritrea.I lived at the site so I got hit by millions of watts for 3 years. It is a wonder I am still alive.Has insanity been proven to be a side effect of high power HF? If so maybe I can get disabilityThis forum has reminded me of this.What kind of health supplements should I take to combat the side effects?

author: Delta
author_rank: Super Contributor
timestamp: September 15, 2015, 10:11:46 am
content: Take some homeopathic batteryiserer pills...

author: Halcyon
author_rank: Unknown
timestamp: September 15, 2015, 10:16:43 am
content: Oh stop your complaining! What about these people who live near wind turbines or close to Wi-Fi access points? They are the ones who are truly struggling!;-)

author: German_EE
author_rank: Super Contributor
timestamp: September 15, 2015, 10:21:30 am
content: "What kind of health supplements should I take to combat the side effects?"Fresh air, sunshine and lots of chocolate.

author: nitro2k01
author_rank: Frequent Contributor
timestamp: September 15, 2015, 10:22:53 am
content: Quote from: ez24 on September 15, 2015, 09:56:05 amReminded you of what? Insanity, disability, high power RF or all 3?But, RF is non-ionizing radiation, so unless you put your head in the way of the beam and got your head cooked, you should have no permanent damage from the radiation. And likewise, you probably didn't receive much of the radiation energy at all. In the control room, the energy would be transported through rigid coax cables, the "pipes" coming out from the top of the unit. If it was leaking, you would lose valuable power from reaching the antenna!And the signal strength would be diminshed according to an inverse square law. Imagine the signal being spread out over an imaginary sphere, with an area growing with the radius of the sphere, ie your distance from the antenna.All in sall, not much to worry about. Unless your post wasallin jest and you know all of this already.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 15, 2015, 10:35:22 am
content: I know lots of broadcast engineers. Many with no consequences from working safely around high power transmitters. What frequencies did it operate on without having a guess? AN/FRT-62 by TMC.The only people that develop problems, are the foolish who disable interlocks and insist on crawling in the cabinet with the HV on, and the others who expose themselves to high band VHF and above due to leaky gaskets and or direct antenna radiation.A properly screened room will mostly eliminate daily exposure from high power RF. Then again I have heard of people looking into a waveguide and wondered why they developed cataracts or worse.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: September 15, 2015, 11:02:10 am
content: I used to work with a colleague back in my RF days who was utterly convinced that exposure to high power RF caused people to have more male than female children. I'm pretty certain that there's no actual evidence for this and it's all just conformation bias in his head but he could name tonnes of ex-colleagues who only had male kids. He had 8 kids and was satisfied that that was a statistically significant number

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 15, 2015, 11:12:00 am
content: No, you didn't get hit by millions of watts. If you did, you would literally vaporize. Don't know if you ever saw any catastrophic failures, but power levels on the order of that are awesome indeed, and not something you'd want to interact with, physically speaking!Going to guess, large ceramic tube? Got any pictures or stories to share?Tim

author: KJDS
author_rank: Super Contributor
timestamp: September 15, 2015, 12:37:24 pm
content: I once did a safety survey on a medium wave transmitter site that had several transmitters each running at hundreds of kilowatts. Everywhere away from the antennas were way below the ICNIRP guidelines.

author: ez24
author_rank: Super Contributor
timestamp: September 15, 2015, 08:38:43 pm
content: Quote from: KJDS on September 15, 2015, 12:37:24 pmWhat is "away"?FYIThe transmitters, barracks, mess hall, misc were all in one building completely surrounded 360 by the antennas no more than 100 ft from the barracks. What bothers me the most is my lack of memory on the transmitters. Almost like my mind has been wiped clean (effects of over exposure to HF ?). For 45 years I never even thought of the transmitters. It wasn't until I joined this forum and came across ham operators and then thinking they use transmitters.This post was not in jest. It is scary to lose one's memory.There is hardly anything on the internet about where I was, just that the Navy had a transmitter site at Guru.And I have no photos of the transmitters (I cannot remember if we were forbidden to take them).The first photo is the transmitter site. The black arrows are the outside limits of site (stone wall) and the red oval was where the transmitter/barracks were. All traces of the Navy buildings are gone. But since we had a basement, I think what you see is concrete from the foundations. It would cost too much money to remove.During the civil war all the buildings were burned down. All buildings seen in photo were built after the US left. Antennas surrounded the area in the red oval within the boundary indicated by the black arrows.Google map of area:https://www.google.com/maps/@15.0043552,39.0437664,720m/data=!3m1!1e3Just had to show where I had my accident (nothing around the area)https://www.google.com/maps/@15.087098,39.0196759,356m/data=!3m1!1e3

author: AF6LJ
author_rank: Unknown
timestamp: September 15, 2015, 09:07:00 pm
content: From everything I have seen on the subject you shouldn't need to worry in regards to HF power levels, VHF and above it becomes an issue though.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 16, 2015, 05:16:47 am
content: 45 YEARS? I'm lucky if I remember something from last year!Memory is only what you use of it. If you truly haven't thought of it in that time, it's a wonder you remember it at all!Remember (ha), people regularly overestimate their memory capability; and feel really bad when they remember much less (and what's worse: much less accurately!) than they think they should. Eyewitness testimony is notoriously bad, easily one of the worst forms of evidence, scientifically speaking, that's legally admissible in court.Brains are weird...Tim

author: Srbel
author_rank: Frequent Contributor
timestamp: September 16, 2015, 06:53:37 am
content: I remember reading about findings of Russian scientists about the effects of high frequency radio waves on human cells. The conclusion was that everything under 800 MHz is safe.

author: Zero999
author_rank: Super Contributor
timestamp: September 16, 2015, 08:26:39 am
content: Quote from: Srbel on September 16, 2015, 06:53:37 amI'd be interesting to see the research.I believe it depends on whether you're talking about the near or far field, as well as the wavelength.It's true that at longer wavelengths the human body won't absorb much radiation because the wavelength is huge, compared to the size of a human. Try putting some tiny insects in a microwave and note they won't get zapped because they're so small compared to the 120mm radiation.In the near field it depends on the antenna, as much as frequency.

author: Towger
author_rank: Super Contributor
timestamp: September 16, 2015, 08:41:54 am
content: I know 3 people who died from rare forms forms of cancer, who would have been exposed to high levels of RF in their past:1 Amateur radio/Ham operator.2 Research Physics professor. He worked on a lot of military stuff. He would come over to Ireland but would no go to main land Europe, in case he was kidnapped or knocked off. We though he was nuts, but one of his ex Co workers was killed by mossid in France.3 Ex airforce doctor. He did a lot of flying on the death watch bombers. Doing tests on the flight crews. In his own words, they would not be allowed to those test these days...He never said any more about them.

author: Towger
author_rank: Super Contributor
timestamp: September 16, 2015, 08:43:19 am
content: BTW They were all in their 70s when they died.

author: KJDS
author_rank: Super Contributor
timestamp: September 16, 2015, 09:26:42 am
content: ICNIRP guidelineshttp://www.icnirp.org/cms/upload/publications/ICNIRPemfgdl.pdf

author: Srbel
author_rank: Frequent Contributor
timestamp: September 16, 2015, 11:18:18 am
content: Quote from: Hero999 on September 16, 2015, 08:26:39 amYes, nearfield. It was mobile phone related. They found that there is not only thermal effects but also other effects on the human cells. The cell wall would rapture under the influence of the radio waves, an the content of cells would leak out or something. They tested it on rats, and concluded that it does not happen if the frequency is under 800MHz or thereabouts.Can't remember where have I found that research, I read it maybe like 5 years ago.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 16, 2015, 11:46:48 am
content: So you mean they lived an average life span for someone of that era in their 70's?Quote from: Towger on September 16, 2015, 08:43:19 am

author: Towger
author_rank: Super Contributor
timestamp: September 16, 2015, 12:40:13 pm
content: Quote from: Quarlo Klobrigney on September 16, 2015, 11:46:48 am

author: Zero999
author_rank: Super Contributor
timestamp: September 16, 2015, 05:04:52 pm
content: Quote from: Towger on September 16, 2015, 12:40:13 pmYes, exposure ionising radiation is a common cause of cancer but radio is non-ionising radiation and does not cause cancer.

author: LaserSteve
author_rank: Super Contributor
timestamp: September 16, 2015, 07:21:32 pm
content: If you worried about having only male children, become an Airline or Air Force pilot. Some statistical studies show pilots tend to have more daughters. No one has a good reason for this yet..Steve

author: Delta
author_rank: Super Contributor
timestamp: September 16, 2015, 08:09:34 pm
content: Quote from: Srbel on September 16, 2015, 11:18:18 amWell I for one would be glad to have my cell walls raptured up to heaven, albeit if the innards of my cells got sent down to hell...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 17, 2015, 05:28:20 am
content: Quote from: LaserSteve on September 16, 2015, 07:21:32 pmTestosterone levels I would think.Tim

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 17, 2015, 10:44:24 am
content: I imagine powerful RF like that could be dangerous though wouldn’t it? Like if you were to disconnect the rigid coax and put your hand in it, would it be bad? Or climb the tower while the transmitter is on? But the further away you are from tower the less exposure you get, at an exponential rate I imagine. A microwave oven is about 1200w and that cooks food after all. Though I guess the frequency also plays a big role. The part that scares me the most about high power RF is not skin burns but blindness. A microwave magnetron in open air will blind you pretty much instantly.Always incredible to see these types of installations though. Dave has a video from a tour of a TV station, pretty cool stuff. Some of the equipment is in the background when he does mailbag, he had done a tear down of it. I was reading about this one AM radio station in the states that was so powerful people's light bulbs in the area would actually stay lit dimly from the RF. At some point it was going right into Canada and they had to build these special towers to "intercept" the RF so it gets weaker. I think it was like 500kw or something like that.

author: Zero999
author_rank: Super Contributor
timestamp: September 17, 2015, 11:50:16 am
content: It's not just the power output or frequency but how concentrated the beam is.A large bonfire could easily be outputting more than 500kW of radiation (mostly in the IR but there will be some in the microwave band as well as the visible) but because the energy is radiated in all directions so one has to be pretty close to it to suffer burns or eye damage.A magnetron produces a more concentrated beam of radiation so it's much more dangerous. Yes it's true that 2.45Hz penetrates the human body more than IR so it presents a greater danger to the internal organs but the main hazard is the concentration of energy. An IR laser with a power output of just a couple of Watts will blind you instantly.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 17, 2015, 12:04:45 pm
content: Well no, magnetrons don't produce more concentrated beams than IR...Lasers can cause instant blindness due to vaporizing the retina in spots, but magnetrons certainly won't do the same. If you're in a field intense enough to do that (say a military radar), you're damn well going to feel it on the rest of your body, and run the fuck out of there because it feels like being roasted alive (which is what's happening)!Eyes are basically water, about 8 mL worth. Which might be damaged quickly by a modest 5C temp rise, which will take 170 J, or over 1kW actually absorbed by the eye and nothing else to cook it in "a fraction of a second" (which is still considerably longer than 'instantaneous', but I'll give this one for human terms of 'instantaneous'). Which would be an impressive feat, in the middle of a face, for a microwave field no more energetic than 1kW.I don't suggest pointing the magnetron antenna tip at your eyeballs, but I don't find common magnetrons themselves to be a special concern around things made of meat (except for long exposure).Tim

author: VK5RC
author_rank: Unknown
timestamp: September 17, 2015, 12:22:57 pm
content: @ez24 memory is not a limitless resource, from my understanding reasonably frequent use of a memory is needed to maintain it although some are locked in at an early stage, typically by very strong emotional stimuli.There are age related changes in cognitive function, one of the main ones is the decline in multi-tasking. I am noticing this in my early 50s, to a subtle degree, esp when driving a car, previously could do lots of stuff e.g. drive close to the speed limit, radio up loud, look at the pretty girls etc. Now if the traffic gets busy the radio goes down, eyes on the road.Anxiety can also cause an apparent cognitive deficit by diverting attention so worrying about your memory won't help!!! HiHi.

author: AF6LJ
author_rank: Unknown
timestamp: September 17, 2015, 01:01:53 pm
content: Quote from: Hero999 on September 17, 2015, 11:50:16 amThe above statement is not true a magnetron radiates like a 1/4 vertical antenna.The output terminal is a probe that is designed to be inserted into a waveguide. The Waveguide gives it directonality, and concentrates the enegry. At power levels seen in microwave ovens it is still harmful, without a waveguide. .

author: Zero999
author_rank: Super Contributor
timestamp: September 17, 2015, 04:51:20 pm
content: Quote from: T3sl4co1l on September 17, 2015, 12:04:45 pmIt depends on the wavelength of IR which covers a huge bandwidth from about 300GHz to 400THz. The shorter wavelengths will penetrate deep enough to damage the retina but the longer wavelengths will be absorbed closer to the surface of the eye and cook your eyeball.Quote from: AF6LJ on September 17, 2015, 01:01:53 pmYes you're right, I stand corrected.

author: SeanB
author_rank: Super Contributor
timestamp: September 17, 2015, 05:17:53 pm
content: Problem with the eye is that the cornea has no actual pain receptors, only the lids and the inner layers have nerve endings. Thus you will not feel pain from having the actual cornea cooking, though it only has to rise over 45C to actually cloud over from the proteins denaturing. You often find welders with corneal damage from looking at the unshielded arc when striking.As to the radio station broadcasting over a border and needing to make a directional array that is all a matter of changing the radiation pattern from an omnidirectional to a directional one, by using extra antennas fed with a phase shifted signal ( really large high power air cored inductors and high voltage capacitors in a doghouse near each antenna element to do the phase shift) so there is a higher power signal radiated in the desired direction, with a reduced pattern ( along with some nasty side lobes as well) to the chosen side. Basically a very large Yagi antenna, just with the phase shift provided by LC circuits, not by making reflector elements longer and directional elements electrically shorter.

author: calexanian
author_rank: Super Contributor
timestamp: September 18, 2015, 08:02:49 pm
content: +1 for HF is less of a concern. Exposure limits become more of a concern as frequencies increase. Additionally most of the equipment used in military/commercial applications used hard line and lots of shielding in their respective enclosures. Where things get tricky is VHF and above high power experimental things where people are hovering about in close proximity to very high power high frequency and more thought is given to experimentation and testing rather than safety. Generally speaking though in a commercial piece of equipment whos antenna radiating surface is up a tower outside somewhere a hundred feet or more away you have little to worry about. If you are 10 feet from a multi kilowatt UHF transmitter antenna I would say find a new job.

author: AF6LJ
author_rank: Unknown
timestamp: September 18, 2015, 10:52:05 pm
content: Just to add a date point to this.My Paternal grandfather was an iron worker he had his own business providing parts for the Cold War. He had iron worker's cataracts. I pestered my father to take to me Grand-Pa's business and got to see what went on there. The amount of IR radiation this man subjected himself to was amazing. Heat treating special missile parts in a -40 degree caustic soda bath that were orange hot when they came out of the furnace, it was like a walk through Hell.He had his eyes needled twice for cataracts. An amazing man who learned metallurgy when it was still an art.IR is much worse than RF when it comes to the damage it can do.

author: SeanB
author_rank: Super Contributor
timestamp: September 19, 2015, 01:29:48 pm
content: Snap, Grandpa was a patternmaker, at a foundry that made munitions. The patterns he made are probably still in use, as bomb design has not really changed much since WWII, though the accuracy has improved somewhat. They all still hit the ground, but the spread has improved from "somewhere within vision" to "Don't be the target".Still have his retirement dish they made for him there.