john@anasaz.UUCP (John Moore) (06/26/90)
In article <85@sierra.STANFORD.EDU> siegman@sierra.STANFORD.EDU (siegman) writes:
]Please, would sometime tell me why, in all the discussion over
]Brodeur's claims of damage caused by ELF radiation from VDTs, there
]seems to be no mention at all of ordinary TV?
]
]After all, television sets and VDTs are essentially similar devices,
]with overlapping technical specifications; TV has been omnipresent for
]decades; children are reported to watch TV for, what, 20+ hours/week
]on average; people sit with TV sets on their dinner tables night after
]night.
]
]Isn't ordinary television a massive, world-wide, decades-long
]experimental test, totally disproving Brodeur's claims?
No. Most people don't sit as close to TV as they do to VDT's. Brodeur's
claim is based on some good epidemiological studies (but not about
VDT's), backed up by some good (but very hard to explain) lab experiments.
If Brodeur were the one making the claims, I wouldn't pay any attention.
However, there is also evidence from responsible scientists.
--
John Moore HAM:NJ7E/CAP:T-Bird 381 {ames!ncar!noao!asuvax,mcdphx}!anasaz!john
USnail: 7525 Clearwater Pkwy, Scottsdale,AZ 85253
Voice: (602) 951-9326 FAX:602-861-7642 Advice: Long palladium, Short Petroleum
Opinion: Support ALL of the bill of rights, INCLUDING the 2nd amendment!post@hpfcso.HP.COM (Dave Post) (06/26/90)
Siegman wonders: >Please, would sometime tell me why, in all the discussion over >Brodeur's claims of damage caused by ELF radiation from VDTs, there >seems to be no mention at all of ordinary TV? Perhaps because it is endemic to our culture. Nobody thought to think about it. >After all, television sets and VDTs are essentially similar devices, >with overlapping technical specifications; TV has been omnipresent for >decades; children are reported to watch TV for, what, 20+ hours/week >on average; people sit with TV sets on their dinner tables night after >night. >Isn't ordinary television a massive, world-wide, decades-long >experimental test, totally disproving Brodeur's claims? No, actually, it does not. 40 years ago, the major behavior problems in public schools were: talking, pushing in line, running in halls, and chewing gum. Now it is vandalism, drugs, assaults and rapes. No. I'm just kidding. But I WAS tempted to leave it look serious. :-) David Post davep@hpfcpp.fc.hp.com hplabs!hpfcla!post
grr@cbmvax.commodore.com (George Robbins) (06/27/90)
In article <3710@rodan.acs.syr.edu> amichiel@rodan.acs.syr.edu (Allen J Michielsen) writes: > In article <85@sierra.STANFORD.EDU> siegman@sierra.STANFORD.EDU (siegman) write > >Please, would sometime tell me why, in all the discussion over > >Brodeur's claims of damage caused by ELF radiation from VDTs, there > Except for; > 1. Most tv's have a shield (especially older ones) across the face that helps > to block stray & non desired electrons. Monitors, generally don't have any > screen or pixel shield. Most color displays have some attempt at shielding, most monochrome don't, be they TV's or VDT's. Older televisions used a separate piece of glass for "implosion protection", newer televisions and VDT's typically have a heavy duty or laminated faceplate. It is also possible to use leaded glass to minimize X-ray emission, but this form of protection isn't visible. > 2. Tv's use a much lower scan rate & generate lower energy in that range. TV scan rates aren't much different from VDT's and since they typically have larger screens, probably generate more energy. High resolution graphics displays may be a different matter. > 3. It is very rare that users sit in front the tv screen 18 to 30 inches away. Got one right at least... >4. Tv's in this country are tested, rated, and done my major mfg with liability > insurance. Many/most computer monitors are not tested or rated, if done, > a lower class rating is o.k., as long as the mfg classifies it as a not > a consumer item. Further, they are fly by nighters, how can anyone sue a > fly by night or samnung without offices in the us, etc... Nonsense. Most "commercial" grade equipment is made to better standards than consumer equipment. Most of the VDT's in commercial use aren't fly by night, those are the ones bought for use with cheap clones for home use. Most of these require UL or similar testing to allow unrestricted retail sale. > 5. It might be better to believe that the emissions cause long term quality of > life problems. And/or possibly MAY cause genetic damages that may not be > observable for several generations. By then, who knows what may be blamed > wrongly. If the belief was based something more than factoids and scare stories, then I'd almost agree, but most of the anti-VDT noise is coming from labor groups who have realized that doing drudge work in front of a CRT in a high pressure/ productivity oriented situation is a miserable way to make a living. It's probably not healthy either, but it's well to keep an open mind whether the VDT is the cause of the problem, or simply the tool that enables this particular form of workplace. -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing: domain: grr@cbmvax.commodore.com Commodore, Engineering Department phone: 215-431-9349 (only by moonlite)
john@anasaz.UUCP (John Moore) (06/28/90)
In article <12967@cbmvax.commodore.com> grr@cbmvax (George Robbins) writes:
]If the belief was based something more than factoids and scare stories, then
]I'd almost agree, but most of the anti-VDT noise is coming from labor groups
]who have realized that doing drudge work in front of a CRT in a high pressure/
]productivity oriented situation is a miserable way to make a living. It's
]probably not healthy either, but it's well to keep an open mind whether the
]VDT is the cause of the problem, or simply the tool that enables this particular
]form of workplace.
I used to think the same thing, before I investigated a little bit. It turns
out that there is a significant body of evidence showing biological effects
of magnetic fields near the vertical sweep rate of VDT's, and with the same
amplitudes experienced by some CRT users. Furthermore, there is another
body of evidence that exposure to ELF magnetic fields leads to some
increased incidence of certain cancers.
It is unfortunate that this issue has been snatched up by activists and
Paul Brodeur. It means that reasonable people are apt to deny their claims
simply because the activists themselves have no credibility. However, just
because the claims are asserted by activists does not, per se,
make them invalid.
Also, note that the evidence applies ONLY to ELF magnetic fields. It does
not apply to electric fields, and does not apply to RF energy (unless
amplitude modulated at ELF rates).
--
John Moore HAM:NJ7E/CAP:T-Bird 381 {ames!ncar!noao!asuvax,mcdphx}!anasaz!john
USnail: 7525 Clearwater Pkwy, Scottsdale,AZ 85253
Voice: (602) 951-9326 FAX:602-861-7642 Advice: Long palladium, Short Petroleum
Opinion: Support ALL of the bill of rights, INCLUDING the 2nd amendment!sparks@corpane.UUCP (John Sparks) (07/02/90)
amichiel@rodan.acs.syr.edu (Allen J Michielsen) writes: |1. Most tv's have a shield (especially older ones) across the face that helps |to block stray & non desired electrons. Monitors, generally don't have any |screen or pixel shield. You're talking about a shadow mask, and it is not to block stray electrons, it's to guide the 3 color guns to the correct color phosphors. Monitors do have these also. |2. Tv's use a much lower scan rate & generate lower energy in that range. er, this is nonsense. While it is true tv's generate lower scan rates, it is just a frequency change not 'lower energy'. |3. It is very rare that users sit in front the tv screen 18 to 30 inches away. This is a good point. |4. Tv's in this country are tested, rated, and done my major mfg with liability | insurance. Many/most computer monitors are not tested or rated, if done, | a lower class rating is o.k., as long as the mfg classifies it as a not | a consumer item. Further, they are fly by nighters, how can anyone sue a | fly by night or samnung without offices in the us, etc... You're nuts! Monitors are made to much more exacting standards than TV's are. They have to be, they have much sharper images, and need much tighter controls on the guns, smaller phosphors and shadow masks, etc. They must be FCC approved. |5. It might be better to believe that the emissions cause long term quality of | life problems. And/or possibly MAY cause genetic damages that may not be | observable for several generations. By then, who knows what may be blamed | wrongly. This paragraph doesn't parse at all. In other words: "HUH???" -- John Sparks | | D.I.S.K. 24hrs 2400bps. sparks@corpane.UUCP | | PH: (502) 968-DISK A door is what a dog is perpetually on the wrong side of. - Ogden Nash
caf@omen.UUCP (WA7KGX) (07/05/90)
I'm not sure how this thread wandered off the subject of EMF radiation to X-rays - I guess the fear is, it all Hertz. The amount of X radiation from a CRT is a function of high voltage potential, shielding, and brightness. A Tek storage tube (4014, etc.) uses hundreds of volts for the stored image, not enough to produce X-rays. Small CRTs, especially monochrome, use a low enough HV that few X-rays are produced. Large screen and projection televisions can produce enough radiation to pick up on a Geiger counter. Not enough to sterilize potato salad, but don't let un-fixed cats sleep on it.