Talk:Cage aerial

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I'm not sure if the tag "radio stub" would be correct. Foxjwill 01:20, 10 May 2006 (UTC)

This is a stub. It could use a diagram or a picture or something at least. --ssd (talk) 14:32, 14 September 2008 (UTC)

Wavelength at 1000 kHz most certainly is not 300 m, it's 30 cm. —Preceding unsigned comment added by 124.171.67.58 (talk) 09:17, 7 August 2008 (UTC)

You're confused. 1000khz is 1mhz, which has a wavelength of about 300m. 30cm would be 1GHz. --ssd (talk) 14:31, 14 September 2008 (UTC)

Recommended changes to article for accuracy.

The antenna described in article is a "mast radiator" type of antenna, not a "cage aerial" or a cage dipole. True, the mast is a cage, but that is not the typical meaning of the term. A "cage dipole" is constructed similar to a standard dipole, and may be either vertical or horizontally polarized. The elements are constructed of multiple conductors arranged around spreader-forms. Electrically the multiple conductors appear as one larger diameter conductor, increasing resonate bandwidth. The trade off is found in increased weight, and wind resistance.

Example: http://www.ni4l.com/80-75-meter-cage-dipole-1/

http://n3ujj.com/the_N3UJJ_antenna_project.html

The Soviet Union's Duga radar was a very large array of caged dipoles : https://en.wikipedia.org/wiki/Duga_radar

The Pipers Bag (talk) 16:09, 24 October 2020 (UTC)

@The Pipers Bag: Agree. A mast radiator cage antenna is called a Folded unipole antenna, and already has its own article. The cage dipole antenna as used at Duga is already discussed in the dipole antenna article. This article is redundant and I propose below that it be merged. --Chetvorno^TALK 00:52, 14 March 2023 (UTC)

Yes, there is a connection, but a cage antenna is not a folded unipole; the two different antenna types look similar but (at least in some unipole modes) have electrically distinct modes. Do not dare try to merge the articles. See No no no no NO below.

— Astro-Tom-ical (talk) 04:36, 23 April 2023 (UTC) (K7TLI)

Merge article into Folded unipole antenna

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

To not merge Cage aerial into Folded unipole antenna; to restructure, potentially with a move of some/all material from Cage aerial to Monopole antenna and Dipole antenna. Klbrain (talk) 12:22, 21 December 2023 (UTC)

---

There is no single type of antenna called a "cage aerial". This article lumps together a number of antennas that already have their own articles. A monopole mast cage antenna, the main type this article covers, is called a Folded unipole antenna. A cage antenna in the shape of a "T", as in the picture, is called a cage T antenna and is already discussed in that article. A dipole antenna in the shape of a cage is called a cage dipole and is discussed in that article. This article may be a WP:POVFORK or just redundant, but either way it needs to be merged. --Chetvorno^TALK 00:43, 14 March 2023 (UTC)

Yes, there is a connection, but a cage antenna is not a folded unipole; the two different antenna types look similar but (at least in some unipole modes) have electrically distinct modes. Do not dare try to merge the articles. See No no no no NO below.

— Astro-Tom-ical (talk) 04:35, 23 April 2023 (UTC) (K7TLI)

Thanks for catching that. I agree it shouldn't be merged into Folded unipole antenna, a folded unipole is not a cage antenna. I was in a hurry and didn't look at the Folded unipole antenna article closely enough. Instead it should be merged into Monopole antenna and Dipole antenna. Cheers --Chetvorno^TALK 21:33, 25 April 2023 (UTC)

No no no no NO: Bad idea

Under no circumstances should a cage antenna (or cage element) article be merged with the folded unipole antenna. Like many superficially similar-looking antennas (large loop / halo / small loop; half-loop / half square, both called a Π antenna; center-fed dipole / Carolina Windom; fan dipole / bow-tie antenna) the two antennas are electrically dissimilar.

The clearest distinction I can think of is that a cage element in a vertical or horizontal antenna always has no current running through its center, and usually has no center-line. A folded unipole always has net current flowing in the mast (its "center wire") in a direction contrary to the net current flowing in the outer skirt wires; it only can radiate when those two currents are unbalanced, usually managed by contriving a resonant path that excludes either the central mast or the skirt.

It is part of the design & configuration of the skirt wires that directs the majority of the current to flow either on the inside mast or outside skirt wires, and only in the particular case that one has managed to convince the unbalanced current that it would rather flow on the outside that the unbalanced antenna currents simulate a cage antenna. It is one of the operational modes of a unipole, but the unipole can still be adjusted to operate as a mast radiator, in which case the skirt wires act more like a multi-gamma match than a cage.

A folded unipole always has the need to design-in some way to unbalance the currents in the mast and the skirt wires. A quarter-wave vertical cage antenna never needs any such considerations: There is no central current to unbalance.

It is indeed a very insightful to observe the connection between the two different antenna types, but then again, many antennas are visibly very similar but electricialy different. Steer clear of the folded unipole article.

Astro-Tom-ical (talk) (K7TLI) 04:17, 23 April 2023 (UTC)

Just as a suggestion, what might suit you instead would be to rewrite this article as Antenna cage element or similar: Just going over the benefits of using a cage element instead of a single-wire element, and providing several real-world examples of where it's been done. I would claim that what you folks have noticed as a problem in the article is that there isn't really a distinct cage antenna: It's rather that antennas can have their vertical (or horizontal) single wire elements converted into multi-wire cages in order to simulate a "fat" wire or cylinder. Rather than just using a cage element in one kind of antenna, you can use a cage element anywhere you could have used a single wire.

(And as a technical point, I think that it might be a design mistake to make the capacitive, non-radiating horizontal element of an antenna into a cage: My first impulse is that the cage wires should be arrayed in a single flat layer, in order to maximize capacitance to ground. Although there's a lot I don't know; there could be some practical reason to want a horizontal cage that I'm not familiar with.) (But I do dismiss being able to spin in the wind: It should be guyed to not spin.)

Astro-Tom-ical (talk) (K7TLI) 04:55, 23 April 2023 (UTC)

@Astro-Tom-ical: Okay, I agree, the folded unipole antenna is a shunt-fed monopole, not a cage antenna as this article is covering. I didn't look at the unipole article closely enough. --Chetvorno^TALK 19:57, 25 April 2023 (UTC)

As you point out above, there isn't really a category called "cage antenna", there are cage versions of monopole antennas, dipole antennas and maybe other types. As you mentioned, wire elements of thin wire antennas can be replaced by cages, to increase the bandwidth, or decrease the radiation resistance of end fed dipoles. I feel that, rather than a separate article on Antenna cage element which is not a WP:COMMONNAME and will be harder for readers to find, cage versions of antennas should be covered in the existing article for that antenna type. So I suggest this article be merged into Dipole antenna and Monopole antenna. There is already mention of cage dipoles in Dipole antenna. --Chetvorno^TALK 19:57, 25 April 2023 (UTC)

@Chetvorno: Well, your common-language argument is legit, but I'd say that "cage" is the common term; perhaps the article should be "cage (antenna)". "Element" is just something I tacked onto "cage" prevent my writing from being ambiguous. Your proposal to augment individual articles seems sort of reasonable, but I tend to fret that there would be a lot of duplication between articles: To my knowledge, 'T', 'L', monopole, and dipole antennas have all been made in cage form and published in QST, RadCom, or the ARRL or RSGB Antenna Books; that's at least four distinct articles that would need to have their shared content kept in sync. It seems better if they all could be linked into the common material kept in a single separate article about cage elements, to avoid redundant information and the typical deterioration of shared content (for example, compare the English language antenna tuner article to all / any other language version).
Astro-Tom-ical (talk) 02:04, 28 April 2023 (UTC)

My opinion is these articles still have to have content on cage radiators, whether or not there is a separate Cage aerial article. The thickness of the element affects several properties of a monopole or dipole element, the resonant length ("end effect"), the bandwidth, the input impedance and therefore the feed arrangements. It appears in the equations. I am doing a rewrite of Monopole antenna (see User:Chetvorno/work6, criticism welcome) which includes these factors, and it wouldn't make sense to omit the cage monopole which is used when a thick element is needed. The same applies to Dipole antenna. Cage T antennas are a common type of T antenna, and are included in the article; to remove them would leave a hole. Also, as you noted, the effect of a cage element is different when used for a capacitive topload than when used for a radiating element. The logical place to discuss this is the Monopole antenna article, which has a separate section on the important subject of capacitively loaded monopoles.

So it seems to me having a separate Cage aerial article is redundant, in addition to the fact that the term "cage antenna" is not used in antenna literature. There is no mention of the term in Balanis, Kraus, Johnson & Jasik, Carr & Hippisley], Kumar, Stutzman & Thiele, Volakis or the ARRL Antenna Book --Chetvorno^TALK 02:44, 2 May 2023 (UTC)

Merge article into Monopole antenna and Dipole antenna

From discussion in section Talk:Cage aerial#No no no no NO: Bad idea above, changed merger tags to propose this article be merged into Monopole antenna and Dipole antenna. --Chetvorno^TALK 23:20, 7 May 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Erroneous bandwidth claim

In contradiction to the unsourced claim in the Purpose section, the cage folded unipole antenna, the main type of antenna this article covers, does not have wider bandwidth than an ordinary mast radiator without the cage wires, according to papers presenting tests on actual antennas by Rackley & Cox and Cox & Moser --Chetvorno^TALK 01:15, 14 March 2023 (UTC)

Wrong: You're conflating unipoles with vertical cage antennas. Please stop it. They're different. The research you cited (Rackley & Cox) (Cox & Moser) only involved testing of folded unipoles. I believe also that they only tested them against standard mast radiators, which already had a "fat wire" radiator. They did not test either the uniples or the mast antennas against a single-wire radiator.

Astro-Tom-ical (talk) 05:09, 23 April 2023 (UTC)

You're right. I didn't look closely enough at the unipole article. Thanks for catching that! --Chetvorno^TALK 21:21, 25 April 2023 (UTC)