Talk:Antenna (radio)

Direct link for Schmitt reference

The reference "Understanding electromagnetic fields and antenna radiation takes (almost) no math", by Ron Schmitt, EDN Magazine, March 2 2000 is linked to a host that is not related to the publisher (very useful article, by the way). Since the article is freely available on the EDN website, shouldn't the link be made to that page? Here is a direct link: http://www.edn.com/article/CA82250.html That page contains a link to the PDF version, which is the same as the one currently linked.

bandwidth limit

The June 2009 Antennas and Propagation article addresses only magnetic dipole antennas, but the conclusions apply to electric dipoles by the symmetry between electric and magnetic fields. It gives a tighter upper bound for loop antenna band widths. Magnetic materials help by lowering H for a given B.

Too much animation (GIF)

Is there some way to freeze the GIFs? A browser setting? I find the writhing pictures nauseating to look at after a few minutes. --Wtshymanski (talk) 03:05, 19 January 2019 (UTC)

I guess they could reduce the frame rate to make it more pleasing, but I have another problem. The animation explaining the half-wave dipole antenna doesn't seem to show the relationship between the length of the antenna element and the wavelength of the RF?

From the diagram, it appears that the element length doesn't matter?

Paging Chetvorno Wikitra (talk) 01:57, 10 May 2024 (UTC)

"I concur". Initially I quite enjoyed the animation but after 10 seconds I moved on to read the text and I found it very difficult to concentrate while the animation is looping. -- Taostlt (talk) 11:53, 21 June 2021 (UTC)

@Wtshymanski and Taostlt: Created the following animation File:Dipole xmting antenna animation 4 continuous HD 1080 12 fps.webm based on the original work by Chetvorno. This video can be considered as a possible substitution for the animated GIF. - DutchTreat (talk) 15:30, 16 January 2022 (UTC)

Thank you @DutchTreat, great work. This appears as a good alternative which both contributes to the understanding of the article while not becoming too distracting at length. Thanks for your attention. Taostlt (talk) 15:55, 1 December 2022 (UTC)

Glad to offer some help. DutchTreat (talk) 21:38, 1 December 2022 (UTC)

Some irritating person edited out a referenced quote

On 1 June 2022‎ User:Ruslik0 deleted the following quote from §Modeling antennas with line equations:

In the first approximation, the current in a thin antenna is distributed
exactly as in a transmission line. — Schelkunoff & Friis (1952)

The quote is cited, pertinent, and correct. Best of all, it is a statement by the "last of the great" mathematical antenna theorists, S.A. Schelkunoff, from the era before computer software (e.g. the Numerical Electromagnetics Code) displaced it in common use. I have restored it, and posted a scold on the user's talk page.

In the face of repeated vandalism-like reversion, I've restored the edits by a seemingly illustrious but deeply ill-informed editor User:Ruslik0. To User:Ruslik0 and any sympathizers, I admonish you to stop the editorial rejection of this idea: The cited texts explicitly show (consider the quote) that antenna elements actually are well approximated as single-conductor transmission lines, however bizarre the idea might seem.

Modeling antennas with the telegrapher's equations isn't a new idea, and isn't personal research. It's been done throughout the last century, and continues to be handy for some applications. The reason that Raines wrote his 2007 book (confusingly titled Folded Unipole Antennas, it's not quite that specialized) was to attempt a revival of sorts for this old technique.

There seems to be an epidemic of people who think they're competent at antenna engineering, possibly because of a degree in physics or an undergraduate degree in electrical engineering who don't understand how to model antenna segments as transmission lines and are hostile to the idea – even though the standing text actually does mention (grudgingly) that this is a procedure that is still actually done.

For example, copious examples in QST and QEX show some radio amateurs' simple antenna designs are based on transmission line formulae, although sensible antenna builders are still careful to model a back-of-the-envelope design with some NEC-based software, or work-alike. I also note that since the turn of the century, many amateurs and electrical engineering college student guess designs based on intuition and then go directly to software modeling.

Apparently electrical engineers educated in this century, who have not had a graduate-level antenna theory course, have been (merely) introduced to antenna theory via use of computer-software. I am now given to suspect that undergraduate E.E. courses only bring up transmission line equations for two-conductor transmission lines. It is probably convenient to skip past using transmission line equations for antennas (every straight-wire antenna element is approximately a single-conductor transmission line): Some version NEC software is easier to use.

The revert that I have reversed is a statement in the introduction to one of the most venerable of all textbooks (though dated) on the exact subject of modelling antennas (all forms: monopoles, loops, and dipoles) using transmission line equations. Further, it constitutes an endorsement by Schelkunoff & Friis of the exact subject that the section addresses. They were perhaps the last of the "great" pre-computer antenna theorists, and their book continued to be used for graduate courses in antenna theory into the 1970s (where I first, briefly, encountered it) particularly in graduate courses in electrical engineering.

If you think the quote is a false statement, I say that that belief is an indication of crippling limitation in your understanding of advanced antenna theory. I strongly suggest that if you find yourself among the "that can't be right" crowd of post-1990s physics or radio engineering students, that you read either of the actual books cited (Schelkunoff & Friis, 1952, or Raines, 2007). Schelkunoff & Friis (1952) is available free from the Internet Archive, but it's a hard slog if you're not already familiar with practical antenna building and good at mathematics. (There were several later editions in the 1960s, and I think one in the 1970s, I don't think they are much different.) I recommend Raines (2007) instead: It's not free for download, but lots of what Raines presents is borrowed from Schelkunoff & Friis; and being a this-century writer, his book might be a bit more accessible.

Clearly, if you're hostile to the idea, you need improved education. Don't mess with the quote again, until after you've done your homework. And if you still feel like deleting it, then you didn't do enough homework, or you didn't read the right stuff.
107.116.93.54 (talk) 10:34, 3 June 2022 (UTC)

References

The facts are suitable to be in the article. But having a quote is not the best way to do it. Rewrite it in your own language. Graeme Bartlett (talk) 11:51, 2 December 2022 (UTC)

Semi-protected edit request on 16 March 2024

Text under the first image says patch antennas, but celluar antennas actually use phased arrays crossed dipoles 185.212.13.192 (talk) 17:57, 16 March 2024 (UTC)

 Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. M.Bitton (talk) 22:14, 16 March 2024 (UTC)