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How 'bout you model it with your concept of an "artificial ground", and
let us know the result? You can measure the voltage with EZNEC by connecting the two points to be measured with a wire and inserting a zero amplitude current source in the wire. The source will act like an open circuit, and the voltage will be reported in the Source Data output. After you've determined the voltage relative to your "artificial ground", modify the "artificial ground" and note the effect on the voltage. Then see if you can figure out what the voltage is between the "artificial ground" and the Earth. Or, give us your justification for assuming that it's zero. If it is zero, via what path? As Tom has been saying, the voltage between two points depends on the path you take between them. Roy Lewallen, W7EL Cecil Moore wrote: Ian White, G3SEK wrote: In practice that will means that the voltage you measure between say the end of a whip and ground will depend on how you choose to route the connecting leads to the voltmeter, and how you connect to ground... and above (below?) all on what you define "ground" to be. How about using an artificial ground at the measurement point? -- 73, Cecil, W5DXP |
Roy Lewallen wrote:
After you've determined the voltage relative to your "artificial ground", modify the "artificial ground" and note the effect on the voltage. Then see if you can figure out what the voltage is between the "artificial ground" and the Earth. Or, give us your justification for assuming that it's zero. If it is zero, via what path? As Tom has been saying, the voltage between two points depends on the path you take between them. Wow, you sure ASSume a lot from a simple question. Let's turn it around and you guys prove that the voltage at the ends of a dipole is less than or equal to the feedpoint voltage even though a florescent light bulb is brighter at the ends. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil wrote,
Wow, you sure ASSume a lot from a simple question. Let's turn it around and you guys prove that the voltage at the ends of a dipole is less than or equal to the feedpoint voltage even though a florescent light bulb is brighter at the ends. -- 73, Cecil http://www.qsl.net/w5dxp What causes the light to light up, Cecil, an E field, or a V field? You can't seem to get over the fact that the voltage between two points in a time varying E field may not be unique and thus not measurable. Go read the book I told you to read, Cecil, and you'll understand why. 73, Tom Donaly, KA6RUH |
Cecil Moore wrote in message ...
Tom Bruhns wrote: If you tell me there is a large voltage along a good conductor, then I know there is a very large heat dissipation in that wire. There are large voltages along my open-wire feedline when the SWR is high, but very low heat dissipation in that wire. Hint: think standing waves on the antenna wire. It's TEM line, right? The voltages are practically all ACROSS the line, between the conductors. There is very little voltage ALONG the conductors, just I*R (and note the directions for _that_). Go look up Faraday's Law of Magnetic Induction, and refresh your understanding of Kirchoff's Voltage Law and Ohm's Law as well. Those three pretty much let you figure it all out. Cheers, Tom |
Tdonaly wrote:
Cecil wrote, Bend the ends of a resonant dipole around close to each other and measure the voltage with a shielded differential RF voltmeter. For 100 watts input, you will get almost 1000 volts RMS between the ends, a far cry from the ~70 volts RMS at the center feedpoint. You missed the point, again, Cecil. Carry on. Nope, you missed the point. This ain't rocket science. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
What causes the light to light up, Cecil, an E field, or a V field? You can't seem to get over the fact that the voltage between two points in a time varying E field may not be unique and thus not measurable. Go read the book I told you to read, Cecil, and you'll understand why. Why not just tell me to read the Bible where God is the cause of everything - same difference. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tom Bruhns wrote:
There is very little voltage ALONG the conductors, ... Depends upon how long the conductors are. The difference along a 1/4WL conductor is known to be minimum VS maximum assuming a minimum at one end. Are you saying that EZNEC doesn't display the current distribution on an antenna when I press the 'i' key? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
What causes the light to light up, Cecil, an E field, or a V field? According to quantum electrodynamics, fields don't exist. So are you talking about photons or virtual photons above? In either case, voltage can still be measured by a voltmeter. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil wrote,
Why not just tell me to read the Bible where God is the cause of everything - same difference. -- 73, Cecil http://www.qsl.net/w5dxp That's about the kind of reply I expected, which is too bad. It sort of reminds me of the Catholic clerics who refused to look through Galileo's telescope. 73, Tom Donaly, KA6RUH |
Cecil wrote,
Tdonaly wrote: What causes the light to light up, Cecil, an E field, or a V field? According to quantum electrodynamics, fields don't exist. So are you talking about photons or virtual photons above? In either case, voltage can still be measured by a voltmeter. -- 73, Cecil http://www.qsl.net/w5dxp I see you've gone into objection-stopper mode: write something whether it makes sense or not. Evidently, you don't know what makes the little light light up, or you'd answer the question. 73, Tom Donaly, KA6RUH |
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