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Wikipedia:Featured article candidates/Waveguide filter/archive2

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The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by Ian Rose 10:01, 4 January 2014 (UTC) [1].[reply]

Waveguide filter edit

Waveguide filter (edit | talk | history | protect | delete | links | watch | logs | views)

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Nominator(s): SpinningSpark 17:30, 8 November 2013 (UTC)[reply]

This article was previously nominated and although it attracted some comments there were no supports (or opposes) before archiving. The article is to the same standard and same style as the previous FAs Mechanical filter and Distributed element filter. I am therefore nominating again. SpinningSpark 17:30, 8 November 2013 (UTC)[reply]

Comments from Mark Viking

I've read through this article and made a few minor edits. I'm not an expert on FA criteria, so will mostly comment on content.

  1. The main criticism I have is that the article doesn't really describe in clear terms how a waveguide filters out some frequencies and passes others--what is the intuitive mechanism here? There is a mention that non-resonant frequencies decay down the guide, but why? Are the non-resonant waves absorbed by the guide? Are they reflected back from the input port of the waveguide, and if so, why? I think giving some sort of intuitive picture of the basic mechanism would go a long way toward making this article more accessible.
  2. The history section frontloads the article with a lot of unexplained jargon, which makes the article less accessible. I understand this was discussed in the first archive and is perhaps the way FA articles are done, but it backfires in a technical FA article, where a desire to be comprehensive about the history has the effect of introducing many unexplained concepts.
  3. I am unsure how FA folks balance accessibility with comprehensiveness, but I was dismayed to find, in an article on filters, not a single plot of frequency response, nor any mathematical models of the frequency response in simple cases.
  4. Terms like 'apertures' or 'irises' in the lead should probably be explained in the lead or glossary. I thought to wiki link them, but the target articles were mostly about the optical varieties. Aperture is particularly confusing, as there is a concept of antenna aperture that is completely different.
  5. Bethe was only at Rad Lab a short time but produced his aperture theory while there. -- this needs a citation, perhaps from among the sources (1) H.A.Bethe,’’Theory of Side Windows in Waveguides”, M.I.T. Rad. Lab. Report No.43-27, April 1943., (2) H.A. Bethe,’’Theory of Diffraction by Small Holes”, Phys. Rev. VO1.66, pp. 163-182, October 1944, or Cohn's expansion of the theory (3) S.B.Cohn,’’Microwave Coupling by Large Apertures’,Proc. IRE, VO1.40, pp.696-699, June 1952, taken from this paper.
  6. They are usually made of brass, but aluminium and copper are also used. -- this needs a citation.
  7. More of a question: is it normal to have quite a few red links in an FA article?

Overall, this article is well written and well-cited. I think that if my concerns are addressed (with the exception of the history placement; I'm not sure what can be done there) I will happily support the nomination. --Mark viking (talk) 20:42, 8 November 2013 (UTC)[reply]

I'll deal with all your comments in due course, but I just wanted to address the order of sections issue first. Putting history first started in an earlier filter article at Peer Review when it was suggested that non-technical readers might find the history section more enjoyable and an easier read, so putting it in front of technical details made it a much better article for the general reader. That format has been followed in a series of filter articles, some of which have become Featured Articles. Personally, I have always been a bit dubious about this, but went along with the advice from a non-technical reviewer - it is all too easy to be blind to the difficulties non-technical readers are going to have. You are not the first to make this comment, and really, I agree with you. I am therefore inclined to make the change. However, I wish to wait to see if there are any more comments on this; I do not want to get into the situation where the article is bounced back and forth to please each reviewer in turn. There are also consequences for other articles in the series so this will not be a trivial amount of work and I would like to be sure of consensus first. SpinningSpark 17:14, 9 November 2013 (UTC)[reply]
Thanks for the formatting above. I understand your point of view and have no wish to cause pointless extra work. As a technically oriented editor, I tend to focus on the technical bits. But I could see a nontechnical reader happily ignoring the jargon and enjoying the general history of the devices. I agree, let's see if there is consensus for a change. --Mark viking (talk) 17:56, 9 November 2013 (UTC)[reply]
Responding to the rest of your points;
  • the article doesn't really describe in clear terms how a waveguide filters out some frequencies. I have tried to address this, at least partially, with this edit. The problem here is that waveguide filter covers a broad class of filter using many different mechanisms. It is not really possible to give an overall description except in very general terms. It is a bit like asking for a description of how it works in the lede of the engine article; one cannot even say all engines are rotary, one cannot say they all directly produce mechanical motion from burning fuel (eg steam engine).
  • non-resonant frequencies decay down the guide. I cannot identify the passage you are referring to. Please provide a direct quote.
  • not a single plot of frequency response, nor any mathematical models. This is an article about a technology used to construct filters. It is not about a class of filter based on transfer function. In principle (and often in practice) any desired response can be implemented in waveguide. There is no particular response associated with waveguide filters so it would be inappropriate and off-topic to include them in the article. The series of articles classifying filters by response include for instance Butterworth filter and Chebychev filter and the mathematics and plots will be found there. Any of these can be implemented in waveguide. The series of articles which this article belongs to discusses filter implementation technologies such as Mechanical filter.
  • apertures and irises. Added to glossary
  • Your point #5, the passage is already cited to Cohn, as is the entire paragraph
  • Your point #6, the passage is already cited, but I will add Connor as a direct cite.
  • Redlinks. It is normal in any article to link terms that should have articles. It is not any fault of this article that Wikipedia is not finished, it is everybody else that needs to pull their fingers out :) SpinningSpark 19:20, 10 November 2013 (UTC)[reply]
Thanks for addressing my points.
  • Regarding the point about providing an intuitive explanation, thanks for adding the equivalent circuit explanation, I am sure that will help some folks who have some electronics knowledge to understand these devices a little better. Being a physicist, my intuition is more along the lines of reflection, absorption and propagation of the EM field, so to me a waveguide filters out non-resonant frequencies primarily through reflection of the EM wave back through the input of the waveguide. But such an explanation may not resonate with the general populace. I'll declare myself satisfied here.
  • But thinking about this topic some more made me realize that there are two more points to address. The first is that evanescent mode waveguide filters are not mentioned at all in the article. I'll try to add something.
  • The second is that in the article it is claimed that The limitation to Q in waveguides comes mostly from the ohmic losses, which is fine as far at it goes, but is not the whole story of loss in waveguides. In all real circuits, insertion loss and return loss are also factors affecting overall losses and thus filter performance. Best to mention these, too, maybe in the Reflections and discontinuities section.
With the exception of the two new points, all the previous points I raised have been addressed. Thanks, --Mark viking (talk) 20:05, 12 November 2013 (UTC)[reply]
I agree that a description of evanescent mode filters should be included. It is one of the few design considerations that is unique to waveguide. Reflection loss is not really a component of overall loss in the sense of lost energy. Return loss is a measure of the energy reflected back from the filter, which is an essential part of the operation of the filter. Reflections result in insertion loss so one could say (ignoring ohmic losses and the like) that both are expressions of the transfer function of the filter. Further, I would argue that both of these are general characteristics of filters and so belong in an article on filters generally. Here, they can be wikilinked if the phrases happen to get mentioned, but I don't think we need to go out of our way to discuss them. In fact, they are not just general characteristics of filters, they are general characteristics of all two-port networks. SpinningSpark 22:51, 12 November 2013 (UTC)[reply]
It is clear that I have a broader notion of the scope of this article than you do. But within the narrow scope you suggest, you have addressed the issues above. I will give my Support for promoting this article to FA status. --Mark viking (talk) 06:24, 15 November 2013 (UTC)[reply]
Comments from Catslash
Before commenting, as I suspect there is a prohibition on canvassing support, I need to declare that Spinningspark [invited] my participation.
I notified everyone who has made substantial comments on this article, whether or not they seemed supportive. SpinningSpark 10:47, 12 November 2013 (UTC)[reply]
A few comments on the content before considering the FA criteria:
  • The Multiplexer history section refers to directional filters - which made me think: ¿what's one of those? So I concur with Mark Viking's point 2 above (though I recognize that having the history at the top is standard).
Taken with previous comments, I think we are moving to a consensus to put history at the end, but as I said above, let's wait to see if there are any more comments. It may be that only this editor thinks its a good idea to have it at the beginning. I don't even like it myself. SpinningSpark 10:47, 12 November 2013 (UTC)[reply]
  • Though I am prepared to accept the relevance of some band-limited devices that are not intentionally filters, (see Talk:Waveguide_filter#Filter-like_devices), the Moreno coupler does not come into this category (or else everything is a filter, since everything is band-limited). The Moreno picture needs to be replaced by a Bethe-hole coupler or suchlike.
Done, replaced with Bethe-hole filter. SpinningSpark 10:47, 12 November 2013 (UTC)[reply]
  • In the glossary, the use of free-space wavelength rather than frequency is a bit archaic and is potentially confusing. In the expression for the travelling wave impedance it has to be understood that λg as well as λ itself is varying. In the relation for λg it must be understood that λc is free-space (and in the context, it would be clearer to separate λg on the left hand side). I suppose I could fix this myself though.
Are you wanting to write,
I could go along with that. Or are you looking for
or maybe like this? That seems to me to be unnecessarily complicating a simple relationship. I only included it because it was so simple; arguably, we don't need the exact formula at all in an article like this. SpinningSpark 10:47, 12 November 2013 (UTC)[reply]
I've just realised what your point is about λc. So perhaps you want it written like this,
Yes, I would have written
or perhaps
and
but it is a minor issue - and as you point out, it would suffice to mention that the wavelength and travelling wave impedance in the guide differ from those in free space. --catslash (talk) 01:27, 13 November 2013 (UTC)[reply]
I have amended the expression for guide wavelength as susggested. I don't see much advantage in changing the impedance expressions. The forms in the article are nice and simple and now the λg expression has been changed it can easily be substituted into the impedance expression by anyone wanting it in terms of frequency. SpinningSpark 12:42, 13 November 2013 (UTC)[reply]
I can't really give this much attention for the next couple of weeks - will the nomination stay open that long? --catslash (talk) 01:57, 12 November 2013 (UTC)[reply]
Probably, they are usually held open anyway while there is still an active discussion on the page. Let's make that a request to the FA Director to poke you when s/he is about to archive if you have not returned by that time. SpinningSpark 12:42, 13 November 2013 (UTC)[reply]

History sections One of the FA criteria is comprehensiveness, so I think that this article should have a History section. I was apparently the first to suggest moving History sections "earlier in the article" in the Peer Review for Distributed element filter (which is a FA). I note that in that article the History section follows the Lead and a "General Comments" section, so there is a fair amount of explanation of concepts before History. In the Mechanical filter article (also a FA), the History section again follows the Lead, and an "Elements" section, which again provide more explanation and background before the History section. I have not read all of this article carefully and am not an expert on these filters, but could the current section "General description and principles" be moved so it comes before History? That might solve some of the issues raised and follows the model of the other two FAs on electronic filters. For non-experts if the lead introduces the topic, and there is some sort of overview / general explanation, followed by a history section that shows where these filters were used in the past and today, then I think this gives a better idea of what the article is about. Ruhrfisch ><>°° 05:26, 14 November 2013 (UTC)[reply]

No one has suggested not having a history section at all (at least not here). Your suggestion would not resolve Catslash's issue concerning directional filters, which is not really appropriate to put under general principles. He could easily have pointed to numerous other examples. I request other reviewers to comment here on whether they think Ruhrfisch's suggestion is an acceptable compromise. I will implement whatever seems to be the consensus. SpinningSpark 08:38, 14 November 2013 (UTC)[reply]
I came here because Spinningspark posted on my talk page and mentioned this FAC. I wanted to correct what Spinningspark wrote there (in the PR I said the History section could be moved "earlier in the article", not that it must be the first thing after the lead). I am busy in real life and as I noted have not had time to read this article or even all of this FAC (let alone the previous FAC). I am not an engineer, but I have a pretty good grasp of the physical sciences. I find history helps me to understand these very technical engineering articles better, since it lets me understand how these devices were originally developed and used in the past and now. I note that the material on directional filters is the very last section in the article before the glossary. My suggestion (and it is only that) is that the earlier "History" appears in the article, the more likely the general reader is to get to it and find the material in it helpful. Ping me if for some reason you need me, and keep up the good work, Ruhrfisch ><>°° 12:08, 14 November 2013 (UTC)[reply]

Image check edit

The images all look clear to me. Curly Turkey (gobble) 00:16, 2 December 2013 (UTC)[reply]

More comments from Catslash

Having reviewed the featured article criteria, it seems the only possible objections to the article would be on the grounds of (4) length or (1b.) comprehensiveness. I'd still like to see the History section moved to near the end, after the technical content, so that the article makes sense when read in the order in which it appears - but the FA criteria do not explicitly demand this.

Regarding the length, under a strict reading of the FA criteria the General description and principles section (apart from the Advantages and disadvantages' subsection), might be objected to as a lengthy digression. However the FA review of the Distributed element filter article suggests that most readers need a lot of background explanation before approaching the specific content, so this section is indispensable.

The comprehensiveness depends on the declared scope, which I understand to be any filters constructed from waveguides. There should therefore be a section describing and explaining evanescent mode filters (I am aware that these are now mentioned in History and General description and principles). Also, a question from Mark Viking above makes me wonder whether harmonic absorption filters should also be mentioned (though I would accept no as an answer). Apart from this, I am ready to support FA status for this article. --catslash (talk) 01:22, 22 December 2013 (UTC)[reply]

On the positioning of the history section, we are still short of a definite consensus. Since no one has indicated that this is a show stopper for FA perhaps this can be handled outside the FA process in slower time and broadened to include other electronic articles. I think someone should make a proposal at Wikiproject Electronics and then have the result written into the project article writing guidelines (which are currently less than helpful and could badly use some improvement). Once there is something definite to go on I will happily start amending all the affected articles to comply. At the moment it seems counterproductive to change anything as the next person to come along may have a different opinion.
On evanescent modes, you seem to have missed that I added this to the article some time ago after Mark Viking had added evanescent modes to the history. The purpose and advantage of evanescent mode filters are briefly explained. Is that not enough?
On harmonic absorption filters, I know nothing about them. Do you have a source that could be used to write something from? Are they particularly a waveguide design? A quick google search seems to indicate that a lot of lumped element designs are used for harmonic suppression in electrical power feeds, although microwave filters come up as well. SpinningSpark 03:23, 22 December 2013 (UTC)[reply]
Yes, the position of the History section is a separate issue
Yes, I saw both mentions of evanescent mode filters (one in History, one in General description and principles), but thought that this type of filter perhaps merited a section of its own (on a level with Resonant cavity filter, Dielectric resonator filter, Corrugated guide filter and Stub filter), providing a description of the structure and explanation of the operation of these filters. In my (very limited) understanding, these filters consist of a length of below-cutoff guide with shunt capacitances (screws or dielectrics) at intervals along the guide. The parts of the guide with added capacitance form the resonators, the intervening cut-off lengths provide the coupling. Probably, coax ports are usual - a transition to wider guide seems unlikely.
The absorption filters I'm thinking of have a large number of side-branches of approximately half-width guide (sometimes two rows side-by-side), terminated in matched loads. Frequencies more than twice the main-guide cutoff (maybe in higher modes) get absorbed. I only mention these because Mark Viking asked whether non-passed frequencies were reflected or absorbed. If you deem this sort of device to be out-of-scope, then I'd be happy with that. --catslash (talk) 18:24, 22 December 2013 (UTC)[reply]
I'll see what I can do with improving evanescent mode filter coverage (but I'm not planning any new diagrams). I don't necessarily think that harmonic absorption filters are out of scope but the issue is the lack of a source. I can find nothing useful on gbooks. I can get something similar to your description from vendor's websites, but these are essentially ads and not suitable for a WP reference. I'm still looking elsewhere, but my access to IEEE Xplore has expired since I retired (these people have no respect for pensioners) and nothing else has turned up so far. I suspect that we should be describing "absorption filters" and that harmonic absorption is just one application of this general type. A class of lumped element absorption filters are Zobel networks (although they are not usually described in that way) which I do know a lot about but I really have no idea if the waveguide version follows that kind of topology. SpinningSpark 19:48, 22 December 2013 (UTC)[reply]
A paragraph explaining the structure/operation of evanescent mode filters with no diagram would suffice. Absorption filters are atypical of filters and I would be happy to forget them. I cannot think of any other filter types that I would consider in-scope - and so that would for me tick the comprehensiveness box and secure my support for FA status. I have given up on ieeexplore and now have no direct access. Content always contrived to be outside my subscription anyway - it's a complete rip-off. --catslash (talk) 23:05, 22 December 2013 (UTC)[reply]
Ok, both of those are done. I got some IEEE papers on absorption filters from WP:LIBRARY. SpinningSpark 21:18, 24 December 2013 (UTC)[reply]
  • support: the necessary boxes are now ticked. --catslash (talk) 21:47, 24 December 2013 (UTC)[reply]

Note -- Given this has some support, the last review only closed due lack of comment, and it's the silly season, I'm prepared to leave this open longer than we might normally. It does need at least another set of eyes on it, however, and a source review -- I'll post requests for both at WT:FAC. Cheers, Ian Rose (talk) 01:30, 27 December 2013 (UTC)[reply]

Comments from Quadell edit

This topic is difficult for the non-specialist to understand, and undoubtedly that makes writing this a challenge. This article requires more introductory explanatory material than Mechanical filter or Distributed element filter. (Neither of those needed a glossary.) In many ways, this article feels more like a chapter in a textbook that what a Featured article typically looks like. My first impression when looking at this nomination was (a) this topic is way outside my comfort zone, and (b) I don't have a clear concept of what a Featured article on this topic should look like. Because of this, I've avoided the nomination thus far, and I'm probably not the only reviewer to have this reaction. But that's not the fault of the article, so I'm really trying to give this a fair look.

After looking at other Featured articles that require extensive explanation to be clear on what the article is even about—Virus, Aldol reaction, DNA, Oxidative phosphorylation, even Castle—I'm finally convinced that this could be an acceptable way of organizing and presenting information in a FA, even if it doesn't look much like most FAs I'm familiar with. Although the glossary is unusual, I think it's useful and appropriate. Others above have given various opinions about the order and placement of the history section. I agree that this is the "friendliest" section for newcomers, but I really think the reader is better served by having the "General description and principles" section come first. Otherwise, it isn't clear what we're reading a history of. Most similar articles that need a "Here's what we're talking about" section place it before the "history" section.

I'm going to look at this more tomorrow, but for now I'll just give my boring MoS-technicality feedback. WP:LEAD recommends that a lead have no more than four paragraphs; five is not forbidden, but it's discouraged. If the information in this lead can be rearranged into four paragraphs, that would better conform with the MoS. Also, like most articles, this one alternates between using and omitting the serial comma (e.g. "duplexers, diplexers and multiplexers" vs. "satellite communications, telephone networks, and television broadcasting"). Would you prefer to use or omit them?

More will follow later. – Quadell (talk) 03:41, 27 December 2013 (UTC)[reply]

Thanks for taking a look at this, I appreciate that this is a difficult article to review. Not wishing to be argumentative though, I have to take issue with you on your "textbook" comment. A typical page of a textbook on microwave filters looks like this or this. In other words, very heavy on the maths - it is impossible to study this subject properly without a great deal of maths. For the most part, I have entirely avoided introducing maths into this article except for a few very basic simple relationships, and even these I have moved to the glossary (one of the advantages of having a glossary). I consider this article to be an overview of the different designs of waveguide filter out there; some design equations may be appropriate to an article on a specific type, but not here.
On the order of sections, you have probably noticed that I have been resisting making any change here on the grounds of precedent and the lack of a clear guideline. It is not possible to please everybody here. However, I concede the point made by Ruhrfisch, who wants something very similar to your suggestion, that putting "General principles" in front of "History" would actually be more consistent with prior FA filter articles. I am therefore going to crack and make that change. There will probably need to be some moving of wikilinks to get the first occurence. I will go through those either this evening or tomorrow. Right now I need to go out. SpinningSpark 11:16, 27 December 2013 (UTC)[reply]
Thanks for the response. I see you've been busy this morning. No offense was meant by the textbook comment—this article is clearly more approachable an overview than the textbooks you link to.
Previously I mentioned the five paragraphs in the lead. As I read closer, I see that the lead's final paragraph mostly explains what is not in the article. Key terms from the fifth paragraph, like "dielectric rod" and "optical fibre", are not used outside the lead. MOS:LEAD says "Apart from trivial basic facts, significant information should not appear in the lead if it is not covered in the remainder of the article", and I think that includes information about what is not covered in the article. Therefore I think most of the information in the fifth paragraph of the lead should be moved to the "General description and principles" section (or another section). The remainder (mostly on the post-wall waveguide structure) could easily be incorporated into paragraph four of the lead. Doing so will help to bring this lead into closer conformity with our MoS.
Also, I'm doing some copy-editing and I will continue to do so, but I still need to know whether you prefer to use or omit the serial comma. – Quadell (talk) 13:59, 27 December 2013 (UTC)[reply]
The fifth paragraph of the lead is about the article itself -declaring its scope- and not about waveguide filters as such. It might be better to reduce this paragraph to a hatnote along the lines of:
This article is about frequency-selective filters made from waveguide in the narrowest sense of the word waveguide -a metal pipe conveying microwave energy- and including post-wall waveguide. For filters built from transmission lines such as microstrip or stripline, see distributed element filter.
Filters built from optical fibre would only be mentioned if the relevant article exists. --catslash (talk) 17:17, 27 December 2013 (UTC)[reply]
WP:LEAD also requires that the lead should "define the topic" and constraining the article scope is certainly part of that. It seems to me that the four paragraph guideline is entirely arbitrary, I suppose intended to prevent the lede from getting out of hand, and does not need to be rigidly adhered to. Happy to make changes for non-arbitrary reasons though. On the serial comma, my usual practice is to only use it when it is required to do so for clarity. I am pretty sure that there is a guideline (haven't checked) that says keep it consistent within a given article. So since it is needed in at least one place we should have it everywhere. Now it is just a case of finding them... SpinningSpark 20:04, 27 December 2013 (UTC)[reply]
Regarding the serial commas, that's fine, I'll add them when I come across places for them in my copy-editing. (For whatever reason, they jump out at me.) It looks like they're present most of the time anyway.
Regarding the lead, however, I'm afraid I'm unwilling to support a FAC that violates Wikipedia:Manual of Style/Lead section in two obvious and imminently fixable ways. Some parts of the FAC may seem arbitrary to some editors, but FA criterion 2 still requires that they be followed. Of course there will be occasional exceptions where following a given point of MoS would clearly detract from the quality of the article in a specific situation... but in this case, of course the lead would be just as effective if it were organized into four paragraphs, and of course the article would cover the subject just as well if information about out-of-scope waveguides were covered elsewhere. Currently in this lead, more words are devoted to material not covered in the body than are devoted to the history of waveguide filters, which is the longest section of the article; that really goes against both the spirit and the letter of our Manual of Style. – Quadell (talk) 15:09, 28 December 2013 (UTC)[reply]
I've moved the scope information to its own section. Does that solve the problem? SpinningSpark 16:24, 28 December 2013 (UTC)[reply]
Yes, it does. Thank you for being flexible. – Quadell (talk) 15:15, 29 December 2013 (UTC)[reply]
Also, the serial comma usage is now totally consistent. – Quadell (talk) 20:31, 29 December 2013 (UTC)[reply]
  • I don't understand why "Advantages and disadvantages" is a subsection of "General description and principles". As analysis, it seems to me that it should be its own section. (As I am clearly a non-expert, I want to know if I'm off-base in this.) – Quadell (talk) 19:45, 27 December 2013 (UTC)[reply]
    I'm happy to have that as a separate section. My feeling was that general pros and cons belonged in the general section, but I don't think it is important. SpinningSpark 20:04, 27 December 2013 (UTC)[reply]
    That's fine. Do you think it should still be above the "History" section? – Quadell (talk) 15:09, 28 December 2013 (UTC)[reply]
    I don't know what to think about the history section any more, the issue makes my head hurt. My personal preference was to put history at the bottom of articles, but it has been moved up in previous articles to please other reviewers. As I've said to other editors on this page, it is not possible to say what the order of sections should be until we have a project guideline which says what they should be and in the meantime we should desist from moving stuff back and forth. But to give you a more helpful answer, I am still thinking of the pros and cons as general information and if "general" is to go before "history" then it is in the right place. Also note, I have renamed "General description and principles" to "Basic concepts" as the title seemed no longer appropriate with the pros and cons moved out. SpinningSpark 16:24, 28 December 2013 (UTC)[reply]
  • When the article states "Losses in waveguides mostly come from ohmic dissipation losses caused by...", this sounds like a redundancy in the word "losses". (Is the statement analogous to "Losses at Walmart mostly come from financial losses caused by..."?) I honestly don't understand the topic well enough to know for sure, but it sounds like it should be reworded. – Quadell (talk) 19:45, 27 December 2013 (UTC)[reply]
    Agreed, done. SpinningSpark 21:47, 27 December 2013 (UTC)[reply]
  • Captions are usually either noun-phrases (e.g. "Pierce's waveguide implementation of a cross-coupled filter") or complete sentences. The captions of the three portraits are problematic. For the first, I would suggest "Lord Rayleigh first suggested waveguide transmission." (note the period, since it's a complete sentence), although "Lord Rayleigh, who first suggested waveguide transmission" would also work. The second portrait caption is odd, because Hans Bethe is not an aperture theory. I would suggest a sentence like "Hans Bethe produced his aperture theory while at Rad Lab.", though a noun phrase akin to "Hans Bethe, who developed an aperture theory" would also work. (It's hard for me to know how to word this, since the Hans Bethe article doesn't mention aperture theory at all.) The third portrait caption should probably be something like "John R. Pierce made import innovations in cross-coupled filters and contiguous passband multiplexers.", though I'm not sure how to make the wording most accurate. – Quadell (talk) 19:45, 27 December 2013 (UTC)[reply]
    I've tweaked the captions, see what you think. SpinningSpark 21:47, 27 December 2013 (UTC)[reply]
    That's great, thanks. (I added periods, since they are now complete sentences.) – Quadell (talk) 15:09, 28 December 2013 (UTC)[reply]
  • Is this correct, or is it a typo? "These made Richard's work more usable in unbalanced and waveguide formats..." Is the "and" spurious?
    No, it isn't spurious. "Unbalanced" is a different format from "waveguide". It refers to formats where the return path of the current is through ground or the shielding such as coaxial cable or microstrip (as opposed to balanced formats like twisted pair where identical conductors are provided for the current in both directions). We could write in full "unbalanced transmission line" but that is clunky and I doubt that it would be any more helpful to those that don't know. Instead, I have wikilinked unbalanced. SpinningSpark 17:10, 29 December 2013 (UTC)[reply]
    Okay, great, that link makes it clear. – Quadell (talk) 20:09, 29 December 2013 (UTC)[reply]
  • "Cauer's work was largely developed during the war..." Do you mean WWII? (You'd previously mentioned Kuroda's 1955 work.)
    Yes, WWII, and yes, Kuroda is slightly out of historical sequence, but his work follows on from Richards' whereas Cauer's work is along a different line. SpinningSpark 17:10, 29 December 2013 (UTC)[reply]
    Okay, I specified WWII in the text to make that clear. – Quadell (talk) 20:09, 29 December 2013 (UTC)[reply]
  • I'm having trouble following the grammar here, but it may just be that I'm not familiar with the terminology: "and the stubs will have a lumped-element approximate equivalent circuit of parallel resonant circuits connected in shunt across the line." Is that what you intended to say? (I'm just double-checking.) – Quadell (talk) 20:30, 29 December 2013 (UTC)[reply]
  • Yes, I think so. Can you explain where you think there is a problem with the grammar. By equivalent circuit we mean an analogous conventional circuit that behaves in a similar way. By parallel resonant circuit we mean a capacitor and inductor connected in parallel with each other. By line we mean a pair of conventional conductors along which a transmission can take place. By shunt connection we mean connected between the two line conductors (as opposed to series connection which breaks one of the conductors to insert the components). All four combinations of parallel or series resonator inserted in shunt or series with the line are possible. The sentence is attempting to specify which of those four combinations is germane. SpinningSpark 22:28, 29 December 2013 (UTC)[reply]
    Ah, I see. The thing about English (as opposed to most other Indo-European languages) is it's so difficult to tell what's a noun, what's an adjective, and what's a verb, without some rather specific contextual clues. I think the sentence is fine then. – Quadell (talk) 23:26, 29 December 2013 (UTC)[reply]

Support. This is a very challenging article to assess, but after giving it a couple of careful reads and a very thorough copy-edit, I am now convinced that it passes. It follows our MoS fully and avoids grammar or phrasing problems. The order of sections is at least as good as anything I could come up with, and the lead succinctly summarizes the content. The review given by someone who actually fully understands the topic makes me more confident that all necessary information has been covered in a balanced way (which I'm frankly not competent to assess myself). I'll go out on a pretty sturdy limb and put my signature on it: this article passes our FAC and should be featured. – Quadell (talk) 23:26, 29 December 2013 (UTC)[reply]

Tks Quadell for joining in the review when needed. Can I assume you went over reference formatting? I realise now I mustn't have saved my edit when I thought I posted the source review request at WT:FAC, so if you've done it or can do it that'd be great, just let me know here. Cheers, Ian Rose (talk)
I previously checked the formatting of the references and fixed a few dash problems; everything else looks great there. I had not carefully checked the formatting of the Bibliography. I have now, and I found a few nitpicky issues, which I'll list below. I also did not spotcheck—nor am I qualified to assess whether the article accurately summarizes the sources. – Quadell (talk) 13:15, 30 December 2013 (UTC)[reply]
  • In the bibliography, most entries begin with the name, followed by a comma, and then the title. When there are multiple names, they are separated by semicolons (not "and"), with a comma after the last name. But there are entries with very minor formatting inconsistencies in the punctuation around the names: Belov et al., Huurdeman, Levy & Cohn, Mason & Sykes, Matthaei et al., Montgomery et al., and Young (1963)
  • Also, Edward Cristal's name is given as "Cristal, E.G." in one entry, and "Cristal, Edward G." in another.
  • And the comma after the year at Schumacher looks out of place too.
    All done. SpinningSpark 16:46, 30 December 2013 (UTC)[reply]
I patched up a final few details. The source check is complete, and everything checks out. – Quadell (talk) 18:08, 30 December 2013 (UTC)[reply]
The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.
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