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#1
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The earth
In 1909 Marconi wrote:
http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* |
#2
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The earth
On 4/10/2012 3:22 AM, Szczepan Bialek wrote:
In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* Pilots have no trouble using radios at 45,000 ft. I've never yet seen one require a ground wire. "Houston, Tranquility Base here. The Eagle has landed, and we are talking to you via radio, even though we are not connected to earth, and Marconi said it would lead to celestial mayhem if we were to even try." Houston, I we have a problem... |
#3
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The earth
On 04/10/2012 04:22 AM, Szczepan Bialek wrote:
In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* It obviously never was true. My guess is that the reasoning at the time stemmed from a lack of understanding of far-field electromagnetic wave propagation (and electromagnetics in general), failure to construct apparati of sufficient sensitivity due to technology limitations, and inefficient antenna designs (relative to using the earth as a counterpoise.) I also think Nikola Tesla failed to grasp these concepts as well. Sincerely, and 73s from N4GGO, -- J. B. Wood e-mail: |
#4
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The earth
Szczepan Bialek wrote:
In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* I hope you have your GSM phone firmly connected to earth, or it would operate in violation of Marconi's observations. |
#5
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The earth
In the back of the plane there is a small bucket of soil with a ground
rod stuck in it. At each stop they check to make sure the soil is damp enough to provide sufficient conductivity. On occasion a little salt is added. The ground rod is connected to the frame of the plane using an MFJ Artificial Ground to further ensure that all is well. As well, the bucket is grounded to prevent any possible cathodic action from interfering with the system. :-) Irv VE6BP "NM5K" wrote in message ... On 4/10/2012 3:22 AM, Szczepan Bialek wrote: In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* Pilots have no trouble using radios at 45,000 ft. I've never yet seen one require a ground wire. "Houston, Tranquility Base here. The Eagle has landed, and we are talking to you via radio, even though we are not connected to earth, and Marconi said it would lead to celestial mayhem if we were to even try." Houston, I we have a problem... |
#6
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The earth
"Irv Finkleman" napisał w wiadomości ... In the back of the plane there is a small bucket of soil with a ground rod stuck in it. At each stop they check to make sure the soil is damp enough to provide sufficient conductivity. On occasion a little salt is added. The ground rod is connected to the frame of the plane using an MFJ Artificial Ground to further ensure that all is well. As well, the bucket is grounded to prevent any possible cathodic action from interfering with the system. :-) Marconi added: "By "connected to earth" I do not necessarily mean an ordinary metallic connection as used for ordinary wire telegraphs. The earth wire may have a condenser in series with it, or it may be connected to what is really equivalent, a capacity area placed close to the surface of the ground (Fig. 4). It is now perfectly well known that a condenser, if large enough, does not prevent the passage of high frequency oscillations, and therefore in these cases the earth is for all practical purposes connected to the antennae." So the plane is "connected to earth". Is Marconi right? S* Irv VE6BP "NM5K" wrote in message ... On 4/10/2012 3:22 AM, Szczepan Bialek wrote: In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* Pilots have no trouble using radios at 45,000 ft. I've never yet seen one require a ground wire. Chassis = the ground. Is it true? S* |
#7
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Quote:
A vehicle is not physically bonded to the earth - yet still works. A Mag Mount antenna is not physically bonded to the vehicle body - hence it uses a loop radio to antenna antenna to radio and it changes the way the coax interacts with the antenna. If the radio is bonded to the body and the antenna is bonded to the body the body is capacitive. Turns the whole body into one big counterpoise. Maybe this is the reason why a 102 inch whip works better then a mag mount antenna or one of those silly dual sticks on a truckers mirrors... |
#8
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The earth
Szczepan Bialek wrote:
In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* It was NEVER true; Marconi was wrong. Here's a news flash for you: A lot has been learned about radio since Marconi. The radios on Pioneer 10 worked just fine 12,000,000,000 km from the Earth. |
#9
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The earth
"Szczepan Bialek" wrote in message ... "Irv Finkleman" napisał w wiadomości ... In the back of the plane there is a small bucket of soil with a ground rod stuck in it. At each stop they check to make sure the soil is damp enough to provide sufficient conductivity. On occasion a little salt is added. The ground rod is connected to the frame of the plane using an MFJ Artificial Ground to further ensure that all is well. As well, the bucket is grounded to prevent any possible cathodic action from interfering with the system. :-) Marconi added: "By "connected to earth" I do not necessarily mean an ordinary metallic connection as used for ordinary wire telegraphs. The earth wire may have a condenser in series with it, or it may be connected to what is really equivalent, a capacity area placed close to the surface of the ground (Fig. 4). It is now perfectly well known that a condenser, if large enough, does not prevent the passage of high frequency oscillations, and therefore in these cases the earth is for all practical purposes connected to the antennae." So the plane is "connected to earth". Is Marconi right? S* Irv VE6BP "NM5K" wrote in message ... On 4/10/2012 3:22 AM, Szczepan Bialek wrote: In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* Pilots have no trouble using radios at 45,000 ft. I've never yet seen one require a ground wire. Chassis = the ground. Is it true? S* ********************** No. Spacecraft have no connection to ground, and it is possible to feed balanced antennas in a fashion that there is no ground connection. |
#10
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The earth
"Szczepan Bialek" wrote in message .. . In 1909 Marconi wrote: http://www.nobelprize.org/nobel_priz...ni-lecture.pdf "The necessity or utility of the earth connection has been sometimes questioned, but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." It is still true? S* Such a question would only be asked by someone who is unaware of radio communications by handhelds or by radios in vehicles, aircraft or spacecraft. In other words, no sentient person should ask it. I'm plonking this troll, this goon, this rimless zero. Of course, you can play with him if you wish ... but serious discourse? Ha! "Sal" |
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