Magnetic fields
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I recently was told that the Large TV station tower, 2 blocks from my house, and broadcasts all over the state, is magnetic, not RF, and there is nothing that would shield from this, except moving of course....Just wanted to confirm this was true? and wondered what other types of things have magnetic radiation?
Also, is everything else, such as cell towers, antennas, etc, except household electricity, from a RF type of wave? thanks so much! |
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> I recently was told that the Large TV station tower, 2 blocks from my house, and broadcasts
> all over the state, is magnetic, not RF, and there is nothing that would shield from this, > except moving of course....Just wanted to confirm this was true? No, I think that person doesn't know what they are talking about. TV station frequencies range from 54Mhz (VHF channel 2) to 890Mhz (UHF channel 83). This is within the range of what is known as "RF". Marc |
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In reply to this post by debbie4god39
I don't think that's true. There are antennas that are primarily
magnetic in the near field, but those are at lower frequency than TV. If the antenna is tall the frequency may be fairly low and that would make it harder to shield... the worst case is that the tower shares with AM radio which goes down to about 600kHz. While microwaves can be shielded with foil or metal fly screen, a low frequency like that you'd need thicker metal. The magnetic field from power lines at 60 Hz is pretty hopeless to shield. Here's a graph http://en.wikipedia.org/wiki/File:Skin_depth_by_Zureks.png You want a few times the delta shown, so at 60 Hz that's a few centimeters thick of aluminum! But for AM, 0.1 mm, which would mean several thicknesses of extra heavy duty foil, or very thin sheet metal. On Fri, Sep 9, 2011 at 8:26 PM, debbie4god39 <[hidden email]> wrote: > ** > > > I recently was told that the Large TV station tower, 2 blocks from my > house, and broadcasts all over the state, is magnetic, not RF, and there is > nothing that would shield from this, except moving of course....Just wanted > to confirm this was true? and wondered what other types of things have > magnetic radiation? > > Also, is everything else, such as cell towers, antennas, etc, except > household electricity, from a RF type of wave? thanks so much! > > > [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/eSens/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/eSens/join (Yahoo! ID required) <*> To change settings via email: [hidden email] [hidden email] <*> To unsubscribe from this group, send an email to: [hidden email] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ |
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Bill thanks for this!? If I called the station, do you suggest who I might talk to who might give me this info on the fields?? It is a tall tower....
-----Original Message----- From: Bill Bruno <[hidden email]> To: eSens <[hidden email]> Sent: Fri, Sep 9, 2011 11:49 pm Subject: Re: [eSens] Magnetic fields I don't think that's true. There are antennas that are primarily magnetic in the near field, but those are at lower frequency than TV. If the antenna is tall the frequency may be fairly low and that would make it harder to shield... the worst case is that the tower shares with AM radio which goes down to about 600kHz. While microwaves can be shielded with foil or metal fly screen, a low frequency like that you'd need thicker metal. The magnetic field from power lines at 60 Hz is pretty hopeless to shield. Here's a graph http://en.wikipedia.org/wiki/File:Skin_depth_by_Zureks.png You want a few times the delta shown, so at 60 Hz that's a few centimeters thick of aluminum! But for AM, 0.1 mm, which would mean several thicknesses of extra heavy duty foil, or very thin sheet metal. On Fri, Sep 9, 2011 at 8:26 PM, debbie4god39 <[hidden email]> wrote: > ** > > > I recently was told that the Large TV station tower, 2 blocks from my > house, and broadcasts all over the state, is magnetic, not RF, and there is > nothing that would shield from this, except moving of course....Just wanted > to confirm this was true? and wondered what other types of things have > magnetic radiation? > > Also, is everything else, such as cell towers, antennas, etc, except > household electricity, from a RF type of wave? thanks so much! > > > [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/eSens/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/eSens/join (Yahoo! ID required) <*> To change settings via email: [hidden email] [hidden email] <*> To unsubscribe from this group, send an email to: [hidden email] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ [Non-text portions of this message have been removed] |
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> Bill thanks for this!? If I called the station, do you suggest who
> I might talk to who might give me this info on the fields?? > It is a tall tower.... I'd guess that if you call the station, NOBODY will know anything about it, and will tell you that it's all perfectly harmless, and there's nothing to worry about... Marc |
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The engineer, who may not be there on site most of the
time, will know the frequencies used. The FCC probably knows most of them too. Wikipedia lists radio and tv stations, so if you know the local call letters, you can find out. Antennasearch.com may have info too. On Sun, Sep 11, 2011 at 11:31 AM, Marc Martin <[hidden email]> wrote: > ** > > > > Bill thanks for this!? If I called the station, do you suggest who > > I might talk to who might give me this info on the fields?? > > It is a tall tower.... > > I'd guess that if you call the station, NOBODY will know anything > about it, and will tell you that it's all perfectly harmless, > and there's nothing to worry about... > > Marc > > [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/eSens/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/eSens/join (Yahoo! ID required) <*> To change settings via email: [hidden email] [hidden email] <*> To unsubscribe from this group, send an email to: [hidden email] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ |
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