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I added a paragraph to the article helping to explain why Hertz did not realize the potential practical uses of radio waves
This was recently removed by an editor with the edit comment: "it's not an analogy, they are exactly the same and do travel in straight lines -- I think you mean "didn't anticipate ionospheric reflection"
The first over-the-horizon transmission was by ground waves, not skywaves. Today we are used to the idea that radio waves can propagate beyond the horizon by two methods, ground waves which follow the contour of the Earth, and skywaves which reflect from the ionosphere. But the waves Hertz generated were in the VHF and UHF bands, which did not propagate by these methods, only line-of-sight. Even if he had generated lower frequencies, they wouldn't have traveled much beyond the horizon because he was using horizontal dipole antennas. Ground waves require vertically polarized antennas. Over-the-horizon radio propagation was only achieved by Marconi after he invented the monopole antenna in 1895.
The belief that radio waves traveled in straight lines, originating from the radio wave/light analogy, was held by the first generation of radio scientists: Hertz, FitzGerald, Lodge until Marconi proved them wrong (they even called the first radio receivers "artificial eyes"). In the late 1800s there were already light wave communication methods being used, semaphore and Bell's photophone, which did not require complicated circuits and used the sensitive human eye as a receiver. If radio waves were limited by the horizon like light, as these scientists believed, radio would have no advantage over these simpler communication methods. That's the context of Hertz's comment. @ LaurentianShield: The paragraph I added was unsourced; I'll try to find some sources on this. -- Chetvorno TALK 21:26, 13 February 2017 (UTC)
I have a source I cited on Dicklyon's page, which says that the primary reason Hertz did not believe radio was viable for communication was not the line-of-sight issue, but rather because he did not think the waves would have the strength. In order for him to cause the spark to jump in his receiver, he had to focus his waves using what he called "mirrors". There is a fairly clear direct quote, I just don't have it right now. My main concern in any case was to call radio waves an "analogy" with light. In free space they are identical and both travel is straight lines orthogonal to the E-M fields. Quasi-guided waves (such as around the earth) can "bend" of course, from a variety of factors. I would like to see any wording not muddle this point to new readers who might not understand the subtlety. Meanwhile, when I find the quote I am referring to, I will provide it. LaurentianShield ( talk) 23:40, 13 February 2017 (UTC)
LaurentianShield ( talk) 00:47, 14 February 2017 (UTC)
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![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 |
I added a paragraph to the article helping to explain why Hertz did not realize the potential practical uses of radio waves
This was recently removed by an editor with the edit comment: "it's not an analogy, they are exactly the same and do travel in straight lines -- I think you mean "didn't anticipate ionospheric reflection"
The first over-the-horizon transmission was by ground waves, not skywaves. Today we are used to the idea that radio waves can propagate beyond the horizon by two methods, ground waves which follow the contour of the Earth, and skywaves which reflect from the ionosphere. But the waves Hertz generated were in the VHF and UHF bands, which did not propagate by these methods, only line-of-sight. Even if he had generated lower frequencies, they wouldn't have traveled much beyond the horizon because he was using horizontal dipole antennas. Ground waves require vertically polarized antennas. Over-the-horizon radio propagation was only achieved by Marconi after he invented the monopole antenna in 1895.
The belief that radio waves traveled in straight lines, originating from the radio wave/light analogy, was held by the first generation of radio scientists: Hertz, FitzGerald, Lodge until Marconi proved them wrong (they even called the first radio receivers "artificial eyes"). In the late 1800s there were already light wave communication methods being used, semaphore and Bell's photophone, which did not require complicated circuits and used the sensitive human eye as a receiver. If radio waves were limited by the horizon like light, as these scientists believed, radio would have no advantage over these simpler communication methods. That's the context of Hertz's comment. @ LaurentianShield: The paragraph I added was unsourced; I'll try to find some sources on this. -- Chetvorno TALK 21:26, 13 February 2017 (UTC)
I have a source I cited on Dicklyon's page, which says that the primary reason Hertz did not believe radio was viable for communication was not the line-of-sight issue, but rather because he did not think the waves would have the strength. In order for him to cause the spark to jump in his receiver, he had to focus his waves using what he called "mirrors". There is a fairly clear direct quote, I just don't have it right now. My main concern in any case was to call radio waves an "analogy" with light. In free space they are identical and both travel is straight lines orthogonal to the E-M fields. Quasi-guided waves (such as around the earth) can "bend" of course, from a variety of factors. I would like to see any wording not muddle this point to new readers who might not understand the subtlety. Meanwhile, when I find the quote I am referring to, I will provide it. LaurentianShield ( talk) 23:40, 13 February 2017 (UTC)
LaurentianShield ( talk) 00:47, 14 February 2017 (UTC)
Hello fellow Wikipedians,
I have just modified 2 external links on Heinrich Hertz. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 10:13, 1 November 2017 (UTC)