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#11
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The earth
Channel Jumper wrote:
'Rob[_8_ Wrote: ;789340']Szczepan Bialek wrote:- In 1909 Marconi wrote: http://tinyurl.com/c3j4ghj "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. A mobile device uses the user as the counterpoise. 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... Balanced antennas such as dipoles do not require a "counterpoise". |
#12
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The earth
On 4/10/2012 10:48 AM, Channel Jumper wrote:
'Rob[_8_ Wrote: ;789340']Szczepan Bialek wrote:- In 1909 Marconi wrote: http://tinyurl.com/c3j4ghj "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. A mobile device uses the user as the counterpoise. Incorrect. The antennas used do not need a counterpoise. In fact the user is often a hindrance to the antenna working properly. tom K0TAR |
#13
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The earth
"Channel Jumper" napisa³ w wiadomo¶ci ... A mobile device uses the user as the counterpoise. 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... Not all know that: ""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." S* |
#14
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The earth
Szczepan Bialek wrote:
Not all know that: ""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." S* But it is Marconi's opninion. It is not the truth, it is only an opinion. When you like, you can say he was "not right". Or you can just respect that he had this opinion. Your choice. So we can move on. What is your next question about 1910's scientists? |
#15
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The earth
Rob wrote:
Szczepan Bialek wrote: Not all know that: ""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." S* But it is Marconi's opninion. It is not the truth, it is only an opinion. When you like, you can say he was "not right". Or you can just respect that he had this opinion. Your choice. So we can move on. What is your next question about 1910's scientists? It may be more accurate than you are giving him credit for. It was based upon the antenna designs and frequency ranges in use at the time. All I know is that by the end of WWI, 200 meters was considered to high in frequency to be useable, which is why the US Navy wanted hams to be limited to frequencies above it (or wavelengths below it). The early practical groundless antennas were 1/2 wave, either a dipole or end fed half wave, and is a 100 meter wire practical? A 1000 meter? What frequencies (or wavelengths) was he speaking about? To answer the comment about cell phones, modern ones operate at around 2.1gHz (3G) a frequency that was impossible to produce at the time. PL-259 connectors are called UHF connectors for a reason, when they were designed 30mHz was UHF. And that was 30-40 years later. Geoff. -- Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379 In 1969 the US could put a man on the moon, now teenagers just howl at it. :-( |
#16
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The earth
On 4/11/2012 2:51 AM, Szczepan Bialek wrote:
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... Not all know that: ""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." S* http://home.comcast.net/~disk200/ru.wmv |
#17
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#18
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The earth
"NM5K" wrote in message ... On 4/11/2012 2:51 AM, Szczepan Bialek wrote: 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... Not all know that: ""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." S* # http://home.comcast.net/~disk200/ru.wmv ROTFLMAO Wayne W5GIE |
#19
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The earth
Uzytkownik "Jeff" napisal w wiadomosci ... Not all know that: ""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." S* And those who do are WRONG!! The trouble is that you keep taking old outdated quotes, out of context, and do not understand that theories and knowledge have moved on. Is even one textbooks where is wrote that Marconi was WRONG? Are your transmitters without any earth? I am checking from time to time if your knowledge have moved on. S* |
#20
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The earth
"Szczepan Bialek" wrote in message
... Is even one textbooks where is wrote that Marconi was WRONG? Are your transmitters without any earth? I am checking from time to time if your knowledge have moved on. S* Hello Szczepan. In general, you seem to be looking at outdated techniques and technology. I guess if you were considering photography you would be asking if wet plates were still in use and what would be a recipe for a good emulsion. Of course, film stopped using wet emulsion a century (or more) ago. Wet emulsion wasn't wrong at the time but it definitely is obsolete. If you were considering car technology you might be asking about manual ignition advance/retard. It had its uses but was automated decades ago and most drivers will not be aware of it. Same thing applies to the choke. My radio doesn't need to be connected to ground/earth other than for static/lightning reasons. The theory and technology of radio have made a lot of progress since the time of Marconi. Hope this is of some help. Kindest regards from the UK, Ian. |
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