#21
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Solar storm etc
Sally wrote:
"David Knisely" wrote in message om... You didn't read what I said. I used the word "significantly". I have not seen such a monitor of that size (a computer monitor, *not* a TV), I'm sorry David but I must disagree. The 16" monitor I'm using right now will show significant misconvergence if it is rotated, this shows up as color fringing, especially at the corners. The only way to restore the convergence is to do a manual degauss in the new orientation. Do you have speakers close to the monitor? I'm not saying that a geomagnetic storm will have any direct effect. I'm just saying that the earth's normal magnetic field is strong enough to affect a TV or monitor picture. Any magnetic field will affect TVs and monitors, the obvious question is rather where is the threshold of "noticeable". Compare that threshold with the maximum fluctuation of earth's magnetic field at your latitude. Keep in mind the relatively small surface of your monitor and the small angle of the field vector towards your screen.I dont have the values handy, but I must agree with David that such effects cannot be visible as a direct result of magnetic field fluctuations. Unless (probably) if you have a 25" monitor directed toward heavens and you live in northern Finland. In fact, your case is specific as it suggests the the field can be so curved that it can produce patterns on the screen. The curves would, in fact appear very smooth on our everyday scales. And yes, I agree that nearby speakers and other magnets can also have an effect although I'm not aware of any special magnetic screening on any domestic TV or monitor that I have seen. Many of them do have an electrostatic screen that seems to be some sort of conductive graphite coating. On the other hand components that emit magnetic fields, such as such as loudspeakers and transformers, often do have casings that function as magnetic screens. I think it would be quite difficult to magnetically screen a wide angle TV CRT from the front, since all conventional magnetic screens that I'm aware of contain iron or iron alloys. Maybe the CRT shadow mask could double up as such a screen, which reminds me of ... So, you do have speakers near the monitor. Nc, nc... A child waved a magnet in front of our TV set to see the "pretty colors" and it took months (dozens of switch-on degausses) for that TV to settle down again. I think that in this case it was the shadow mask that got permanently magnetised...or at least it got magnetised for a few months. Your explanation is correct. Minor fluctuations from the TV itself and the environment will eventually randomise the weak residual magnetism. Ivan |
#22
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Solar storm etc
Sally wrote:
"David Knisely" wrote in message om... You didn't read what I said. I used the word "significantly". I have not seen such a monitor of that size (a computer monitor, *not* a TV), I'm sorry David but I must disagree. The 16" monitor I'm using right now will show significant misconvergence if it is rotated, this shows up as color fringing, especially at the corners. The only way to restore the convergence is to do a manual degauss in the new orientation. Do you have speakers close to the monitor? I'm not saying that a geomagnetic storm will have any direct effect. I'm just saying that the earth's normal magnetic field is strong enough to affect a TV or monitor picture. Any magnetic field will affect TVs and monitors, the obvious question is rather where is the threshold of "noticeable". Compare that threshold with the maximum fluctuation of earth's magnetic field at your latitude. Keep in mind the relatively small surface of your monitor and the small angle of the field vector towards your screen.I dont have the values handy, but I must agree with David that such effects cannot be visible as a direct result of magnetic field fluctuations. Unless (probably) if you have a 25" monitor directed toward heavens and you live in northern Finland. In fact, your case is specific as it suggests the the field can be so curved that it can produce patterns on the screen. The curves would, in fact appear very smooth on our everyday scales. And yes, I agree that nearby speakers and other magnets can also have an effect although I'm not aware of any special magnetic screening on any domestic TV or monitor that I have seen. Many of them do have an electrostatic screen that seems to be some sort of conductive graphite coating. On the other hand components that emit magnetic fields, such as such as loudspeakers and transformers, often do have casings that function as magnetic screens. I think it would be quite difficult to magnetically screen a wide angle TV CRT from the front, since all conventional magnetic screens that I'm aware of contain iron or iron alloys. Maybe the CRT shadow mask could double up as such a screen, which reminds me of ... So, you do have speakers near the monitor. Nc, nc... A child waved a magnet in front of our TV set to see the "pretty colors" and it took months (dozens of switch-on degausses) for that TV to settle down again. I think that in this case it was the shadow mask that got permanently magnetised...or at least it got magnetised for a few months. Your explanation is correct. Minor fluctuations from the TV itself and the environment will eventually randomise the weak residual magnetism. Ivan |
#23
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Solar storm etc
Sally wrote:
"David Knisely" wrote in message om... You didn't read what I said. I used the word "significantly". I have not seen such a monitor of that size (a computer monitor, *not* a TV), I'm sorry David but I must disagree. The 16" monitor I'm using right now will show significant misconvergence if it is rotated, this shows up as color fringing, especially at the corners. The only way to restore the convergence is to do a manual degauss in the new orientation. Do you have speakers close to the monitor? I'm not saying that a geomagnetic storm will have any direct effect. I'm just saying that the earth's normal magnetic field is strong enough to affect a TV or monitor picture. Any magnetic field will affect TVs and monitors, the obvious question is rather where is the threshold of "noticeable". Compare that threshold with the maximum fluctuation of earth's magnetic field at your latitude. Keep in mind the relatively small surface of your monitor and the small angle of the field vector towards your screen.I dont have the values handy, but I must agree with David that such effects cannot be visible as a direct result of magnetic field fluctuations. Unless (probably) if you have a 25" monitor directed toward heavens and you live in northern Finland. In fact, your case is specific as it suggests the the field can be so curved that it can produce patterns on the screen. The curves would, in fact appear very smooth on our everyday scales. And yes, I agree that nearby speakers and other magnets can also have an effect although I'm not aware of any special magnetic screening on any domestic TV or monitor that I have seen. Many of them do have an electrostatic screen that seems to be some sort of conductive graphite coating. On the other hand components that emit magnetic fields, such as such as loudspeakers and transformers, often do have casings that function as magnetic screens. I think it would be quite difficult to magnetically screen a wide angle TV CRT from the front, since all conventional magnetic screens that I'm aware of contain iron or iron alloys. Maybe the CRT shadow mask could double up as such a screen, which reminds me of ... So, you do have speakers near the monitor. Nc, nc... A child waved a magnet in front of our TV set to see the "pretty colors" and it took months (dozens of switch-on degausses) for that TV to settle down again. I think that in this case it was the shadow mask that got permanently magnetised...or at least it got magnetised for a few months. Your explanation is correct. Minor fluctuations from the TV itself and the environment will eventually randomise the weak residual magnetism. Ivan |
#24
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Solar storm etc
Sally wrote:
So yes...there could be a connection causual, and electrical! Well done Sally. Thats exactly what I thought reading all the posts... Ivan |
#25
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Solar storm etc
Sally wrote:
So yes...there could be a connection causual, and electrical! Well done Sally. Thats exactly what I thought reading all the posts... Ivan |
#26
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Solar storm etc
"David Knisely" wrote in message om... You didn't read what I said. I used the word "significantly". I have not seen such a monitor of that size (a computer monitor, *not* a TV), I'm sorry David but I must disagree. The 16" monitor I'm using right now will show significant misconvergence if it is rotated, this shows up as color fringing, especially at the corners. The only way to restore the convergence is to do a manual degauss in the new orientation. I'm not saying that a geomagnetic storm will have any direct effect. I'm just saying that the earth's normal magnetic field is strong enough to affect a TV or monitor picture. And yes, I agree that nearby speakers and other magnets can also have an effect although I'm not aware of any special magnetic screening on any domestic TV or monitor that I have seen. Many of them do have an electrostatic screen that seems to be some sort of conductive graphite coating. On the other hand components that emit magnetic fields, such as such as loudspeakers and transformers, often do have casings that function as magnetic screens. I think it would be quite difficult to magnetically screen a wide angle TV CRT from the front, since all conventional magnetic screens that I'm aware of contain iron or iron alloys. Maybe the CRT shadow mask could double up as such a screen, which reminds me of ... A child waved a magnet in front of our TV set to see the "pretty colors" and it took months (dozens of switch-on degausses) for that TV to settle down again. I think that in this case it was the shadow mask that got permanently magnetised...or at least it got magnetised for a few months. Sally |
#27
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Solar storm etc
"David Knisely" wrote in message om... You didn't read what I said. I used the word "significantly". I have not seen such a monitor of that size (a computer monitor, *not* a TV), I'm sorry David but I must disagree. The 16" monitor I'm using right now will show significant misconvergence if it is rotated, this shows up as color fringing, especially at the corners. The only way to restore the convergence is to do a manual degauss in the new orientation. I'm not saying that a geomagnetic storm will have any direct effect. I'm just saying that the earth's normal magnetic field is strong enough to affect a TV or monitor picture. And yes, I agree that nearby speakers and other magnets can also have an effect although I'm not aware of any special magnetic screening on any domestic TV or monitor that I have seen. Many of them do have an electrostatic screen that seems to be some sort of conductive graphite coating. On the other hand components that emit magnetic fields, such as such as loudspeakers and transformers, often do have casings that function as magnetic screens. I think it would be quite difficult to magnetically screen a wide angle TV CRT from the front, since all conventional magnetic screens that I'm aware of contain iron or iron alloys. Maybe the CRT shadow mask could double up as such a screen, which reminds me of ... A child waved a magnet in front of our TV set to see the "pretty colors" and it took months (dozens of switch-on degausses) for that TV to settle down again. I think that in this case it was the shadow mask that got permanently magnetised...or at least it got magnetised for a few months. Sally |
#28
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Solar storm etc
"Anon Imous" wrote in message ... Your explanation is correct. Minor fluctuations from the TV itself and the environment will eventually randomise the weak residual magnetism. This isn't disagreement...I'm just fillling in a few details...there is specific circuitry built into TV sets and computer monitors that exposes the CRT to a fairly strong and rapidly alternating magnetic field that decreases to zero over a period of about one second. This circuit is normally activated at switch-on and, in some cases, can also be manually activated. This same degaussing technique is used on a much larger scale to remove the magnetic fields of submarines and military ships. In the case of my monitor I can produce color fringes by rotating the monitor through 90 degrees *while it is switched on*. The color fringes disappear after a degauss. In the case of my monitor there are no nearby fixed magnetic fields from speakers etc. Sally |
#29
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Solar storm etc
"Anon Imous" wrote in message ... Your explanation is correct. Minor fluctuations from the TV itself and the environment will eventually randomise the weak residual magnetism. This isn't disagreement...I'm just fillling in a few details...there is specific circuitry built into TV sets and computer monitors that exposes the CRT to a fairly strong and rapidly alternating magnetic field that decreases to zero over a period of about one second. This circuit is normally activated at switch-on and, in some cases, can also be manually activated. This same degaussing technique is used on a much larger scale to remove the magnetic fields of submarines and military ships. In the case of my monitor I can produce color fringes by rotating the monitor through 90 degrees *while it is switched on*. The color fringes disappear after a degauss. In the case of my monitor there are no nearby fixed magnetic fields from speakers etc. Sally |
#30
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Solar storm etc
"Sally" wrote in message ...
| "amazure ²°°³" | wrote in message ... | During the solar storm & the one 2 days or so after, my pc's | monitor kept changing picture width slightly (annoying) ! | If your monitor is an older or cheapo model then it could be affected by | changes in line voltage, which in turn can be affected by the distribution | network responding to surges....which may be due to the current geomagnetic | storms. So yes...there could be a connection causual, and electrical! | Sally It's an LG 775N, bought about 2 years ago. Regards. |
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