Talk:Slotted line

Slotted line has been listed as one of the Engineering and technology good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
Review: September 4, 2013. (Reviewed version).

A fact from Slotted line appeared on Wikipedia's Main Page in the Did you know column on 4 June 2013 (check views). The text of the entry was as follows:

Did you know... that a slotted line for microwave measurement can be made for roughly one ten-thousandth of the cost of a network analyzer?

A record of the entry may be seen at Wikipedia:Recent additions/2013/June. The nomination discussion and review may be seen at Template:Did you know nominations/Slotted line.

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Stuff I wrote (but never used) last time we discussed this topic[edit]

Watching File:Falowod linia pomiarowa.jpg‎ alerted me to the fact you are now tackling this subject. Here is a lede I wrote last time we discussed this:

In microwave engineering a slotted line or slotted waveguide is an instrument used to directly observe the standing wave on the transmission line or waveguide feeding a microwave device (such as a transmitting antenna). From a measurement of the magnitude and position of the standing wave's peaks and troughs, it is possible to infer the reflection coefficient and hence the complex input impedance of the device under test. The slotted line can also be used to measure the wavelength of the signal on the line, and hence to determine its frequency.

In industry, slotted lines have largely been replaced by vector network analyzers, which although far more costly, are also far less laborious to use. Slotted lines are still used for educational purposes, and it is still common to state the voltage standing wave ratio (VSWR) due to an impedance.

Since the page is still in your user-space, I have refrained from inserting this material myself - please use or ignore it as you see fit. Here are some references I collected - presumably some of these support the assertions in the above text.

==See also==
*[[Lecher lines|Lecher line]]

==References==
{{reflist|refs=
<ref name="Das">{{cite book
 |last1=Das
 |first1=Annapurna
 |last2=Das
 |first2=Sisir K.
 |title=Microwave engineering
 |url=http://books.google.co.uk/books?id=ZU19Uemy83YC&pg=PA453#v=onepage&q&f=false
 |date=2000-04-01
 |publisher=Tata McGraw-Hill Education
 |isbn=9780074635773
 |pages=453–454
}}</ref>
<ref name="Lee">{{cite book
 |last=Lee
 |first=Thomas H.
 |title=Planar Microwave Engineering: A Practical Guide to Theory, Measurement and Circuits
 |url=http://books.google.co.uk/books?id=uoj3IWFxbVYC&pg=PA247#v=onepage&q&f=false
 |date=2004-08-30
 |publisher=Cambridge University Press
 |isbn=9780521835268
 |pages=247–254
}}</ref>
<ref name="Voltmer">{{cite book
 |last=Voltmer
 |first=David Russell
 |title=Fundamentals of electromagnetics: Quasistatics and waves
 |url=http://books.google.co.uk/books?id=32Qfq-t1FAkC&pg=PA146#v=onepage&q&f=false
 |date=2007-04-07
 |publisher=Morgan & Claypool
 |isbn=9781598291728
 |pages=146–148
}}</ref>
<ref name="White">{{cite book
 |last=White
 |first=Joseph F.
 |title=High frequency techniques: an introduction to RF and microwave engineering
 |url=http://books.google.co.uk/books?id=wYpj-T0aT6kC&pg=PA135#v=onepage&q&f=false
 |date=2004-01-02
 |publisher=IEEE Press (John Wiley & Sons)
 |isbn=9780471455912
 |pages=135–138
}}</ref>
}}<!-- end reflist -->

[[Category:Microwave technology]]

--catslash (talk) 00:07, 5 May 2013 (UTC)[reply]

Remind we where we discussed this before, I have completely forgetten about it. I'm completely cool with you editing in my userspace.

I have come to the conclusion that it is a big mistake to write ledes first. They inevitably do not quite (and sometimes do not at all) end up as a true summary of the article. This causes a lot of grief on review. A far better plan is to pretty much complete the article first, and then write the lede as if it were a mini-article and the article is the only source. Spinning Spark 06:26, 5 May 2013 (UTC)[reply]

It wasn't a long discussion. --catslash (talk) 11:27, 5 May 2013 (UTC)[reply]

GA Review[edit]

This review is transcluded from Talk:Slotted line/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: North8000 (talk · contribs) 13:55, 22 August 2013 (UTC)[reply]

I am starting a review of this article North8000 (talk) 13:55, 22 August 2013 (UTC)[reply]

Wow, taking on two at once. Thanks for the effort, I'll try to keep up with you. Spinning Spark 17:14, 22 August 2013 (UTC)[reply]

It won't be hard, I'm slow. :-) I noticed that both have been waiting for a long time. North8000 (talk) 17:55, 22 August 2013 (UTC)[reply]

I find that's fairly typical for electronics articles. Not many people are willing to review them. Spinning Spark 20:10, 22 August 2013 (UTC)[reply]

Review discussion[edit]

I have comments on two general areas regarding the lead. First it seems to have some sidebar type stuff (especially in the first paragraph) which is not in the body of the article. I was think that some of it might be "too sidebar" for the led (but I could be wrong. But I think that a clearer cut note is that the lead should be a summary of the article and there is material in the lead which is not in the article.

My second area of suggestion is that the excellent material in the "Maxima and minima", "wavelength" and "standing wave ration" sections are core material on saying (in a straightforward manner) what this does and how it is used to do that. My suggestion would be to get more of that into the lead. I would be happy to help. Sincerely, North8000 (talk) 20:48, 23 August 2013 (UTC)[reply]

What do you mean by "sidebar"? You are correct in identifying the three basic measurements done on a slotted line. VSWR especially, is the classic measurement for which slotted lines were used. In fact, the terminology of VSWR is only still with us because slotted lines used to be so ubiquitous. VSWR is very easy to measure on a slotted line but it is not the best parameter to use. If it were not for slotted lines we probably would not ever have used VSWR (which is now slowly dying out) but would always instead talk about reflection coefficient or the corresponding S-parameter. Please feel free to make improvements if you want to. Spinning Spark 23:15, 23 August 2013 (UTC)[reply]

I'll try that. (acting only as an editor, feel very free to revert me) Basically, I was thinking of incorporating more of what is in those three sections into the lead. North8000 (talk) 13:12, 24 August 2013 (UTC)[reply]

By "sidebar" I was thinking as being sidebar to the main points of the article / things that would normally be in the lead. I was thinking of this material: " can still be found in budget applications. Their main drawback is that they are labour intensive to use and require calculation, tables, or plotting to make use of the results. They need to be made with mechanical precision and the probe and its detector need to be adjusted with care, but they can give very accurate results. They are used in conjunction with a microwave power source and usually, in keeping with their low-cost application, a cheap Schottky diode detector and VSWR meter rather than an expensive microwave power meter." North8000 (talk) 13:17, 24 August 2013 (UTC)[reply]

Doubtless that can be improved, but there is a whole section on their "mechanical fiddliness" which needs to be summarised in the lede. I would say that the restriction of their use to budget and academic areas is an important aspect of the subject. There is a whole section on test setups which also needs summarising in the lede. I thought I was doing well to combine all three of these points inot one passage in the lede. Spinning Spark 14:44, 24 August 2013 (UTC)[reply]

Could be and that so far I've missed it in my first couple of passes looking for it. North8000 (talk) 20:13, 25 August 2013 (UTC)[reply]

Looking for what? "Mechanical fiddliness"? Try ==Accuracy considerations==. Spinning Spark 23:33, 25 August 2013 (UTC)[reply]

Between that and a sentence in the "Description" section regarding current usage/non-usage, I can see it now. Sincerely, North8000 (talk) 12:04, 26 August 2013 (UTC)[reply]

For my next comment I need to provide a bit of context. I do a fair amount of published writing and course instruction involving conveying certain technical topics to people who don't know them. And I've been told (and magazines keep coming to me) that I'm pretty good at that. In essence, empathy for the person who is new to the topic, and I tend to be a bit tougher in that area on GA reviews. Regarding this topic, decades ago I aced a couple of transmission line courses but have forgotten or become non-fluent on 98% of what I learned. Also decades ago I had a lot of hands-on experience in RF, but it was in UHF on down. That said....

I think that this article is a bit "hard to learn from". IMO it really needs more of the core statements presented as such written in ways where the 'basics are conveyed without needing to first go learn other terms. This is the only remaining question in my mind. If you prefer, I'll pass it as GA right now as is. The other alternative might be to spend at least a few more days in the area I discussed. Because I don't have your level of expertise and fluency in this area (nor a perspective on the actual main uses of this device....it to spot and fix SWR problems?) ) , I can't just jump in and edit it well in a reasonable amount of time so I'd need your help. Probably via. fixing my errors. :-) I might try a few edits this way. Or I'll just pass it as is if you prefer. Sincerely, North8000 (talk) 10:55, 28 August 2013 (UTC)[reply]

Whether you pass it now or later, I am more than happy to work with you to improve the article. I also don't have a problem with you copyediting the article, even if that results in some errors that need correcting. Spinning Spark 12:44, 28 August 2013 (UTC)[reply]

Cool! North8000 (talk) 13:25, 28 August 2013 (UTC)[reply]

I was wondering if you could tell me these things based on your overall perspective. Three-word answers are fine.

So a general case "sequence of connection" would be Source <-> transmission line <-> slotted line <-> transmission line <-> load. For typical use, would you add or delete anything from that?
More or less. The DUT is often a small device and can be mounted directly on the end the slotted line either using its own connectors or, in the case of an individual component, in a specially made jig. The DUT forms the load of the setup and hence no transmission line is needed at that end. Of course, if one is trying to measure the VSWR of an antenna atop a 100 foot pylon then a connecting line is required for practical purposes. This would normally be the antenna's own feed line and would form part of the thing being tested.

Many test setups also include a precision attenuator between the generator and the slotted line input. This is shown in the photograph and the reasons are explained in the article.
In typical use, is the source a part of the test equipment, or is it a part of what is being tested?
The source is usually part of the test setup. The main measurement that could be made on a source is determining its wavelength (and hence frequency).
Is there a "main" use for this? (e.g. tuning an antenna/the load)? Or maybe not, maybe its a generalized lab instrument for R&D etc.
It is a generalised piece of equipment. It can be used in industrial production settings as well as labs. Formerly, this was very common at microwave frequencies. For instance, early in my career one was used to determine junction capacitance of semiconductor devices in a production test room.
Is there a main parameter that this is used to measure (e.g. SWR)?
Yes, the fundamental thing measured by a slotted line is SWR. That information, together with the position of nodes measured with the vernier allow a number of other parameters to be calculated, notably impedance. SWR of the antenna and feed is very important for transmitters outputting more than a trivial amount of power. Spinning Spark 18:52, 28 August 2013 (UTC)[reply]

Thanks. That helps on what I'll try. Sincerely, North8000 (talk) 20:12, 28 August 2013 (UTC)[reply]

Thanks. Sincerely, North8000 (talk) 13:42, 28 August 2013 (UTC)[reply]

GA criteria final checklist[edit]

Well-written

Meets this criteria. I think that a few areas are still a bit hard to follow, but it's at or above the norm for technical article. North8000 (talk) 14:14, 4 September 2013 (UTC)[reply]

Factually accurate and verifiable

Meets this criteria. North8000 (talk) 17:47, 26 August 2013 (UTC)[reply]

Broad in its coverage

Meets this criteria. North8000 (talk) 12:05, 26 August 2013 (UTC)[reply]

Neutral: it represents viewpoints fairly and without bias, giving due weight to each

Meets this criteria. North8000 (talk) 20:10, 25 August 2013 (UTC)[reply]

Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute

Meets this criteria. North8000 (talk) 13:09, 23 August 2013 (UTC)[reply]

Illustrated, if possible, by images

Meets this criteria. Has 4 images, no non-free images so no article-specific use rationales are required. North8000 (talk) 17:57, 22 August 2013 (UTC)[reply]

Result[edit]

This article passes as a Wikipedia Good article. Congratulations! Sincerely, North8000 (talk) 14:16, 4 September 2013 (UTC) Reviewer[reply]

This article has passed as a Wikipedia Good Article[edit]

(This is "duplicated" here for when the review is no longer transcluded)

This article has passed as a Wikipedia Good Article. Congratulations! Sincerely, North8000 (talk) 14:20, 4 September 2013 (UTC) Reviewer[reply]

Many thanks for all your efforts. Spinning Spark 15:08, 4 September 2013 (UTC)[reply]

Nice work! North8000 (talk) 10:41, 5 September 2013 (UTC)[reply]