Antenna Guru

RF is not 'black magic' – It's Synthesis, Optimization, Analysis and Realization.

Category Archives: science

EW!

Engineer’s Week, that is.

Look with me at ‘our’ celebratory poster for a moment… The e– earth’s blossoming western hemisphere beneath some random stars shuffled together with rising monarch-ish butterflies and framed by tropical flora… shadowy stylized translucent distant skyscrapers hovering beyond the blue horizon like an outsider’s fanciful view of a distant city…

(Would your manager have approved that drawing for release, I wonder?)

Uh, like… awesome, dude…

Celebrate!

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(k)Now-how

Picture0006It is said that if you know your enemies and know yourself, you will not be imperiled in a hundred battles; if you do not know your enemies but do know yourself, you will win one and lose one; if you do not know your enemies nor yourself, you will be imperiled in every single battle.

–Sun Tzu

How does one know, exactly? There is knowledge that __, e.g. 1+1=2. There is knowledge of __, e.g. “I know I left my glasses somewhere.” Knowing that and knowing of are somewhat easily written out and studied.

Then there is knowledge how __. General Sun was referring to the peril of not knowing the how of his enemies/himself. He referred to what know-how is not in attempting to describe what it is.

Know-how can be difficult to pin down. It is implied or inferred in the result of doing.

Perhaps the best way to judge another’s know-how is to ask the question, “Can you show me?”

“Showing how” is “doing now.”

The Internet of Things

Thingernet

The “internet of things” is already here — in the media, at least.

It is not hard to find these types of articles nowadays. Whether or not you think connecting your cow to the www is a great idea, it certainly is a popular topic of conversation. I’m all for it. Here is why, as Linus Pauling famously said

If you want to have good ideas you must have many ideas. Most of them will be wrong, and what you have to learn is which ones to throw away.

But there is a problem with the populist application of internet-to-things that goes unmentioned by the tech writers. The cacophony of “information” that results from Farmer Brown giving Bessie her own cell phone potentially threatens our shared bandwidth. This is the reason we have the FCC and the PTCRB. We need to comply with their rules so we all can remain in polite conversation.

Spurious Emissions

The physics is no longer bewildering to me, as it was thirty years ago when I was thrust into the microwave business, but the rules and regulations can still be−

PTCRB

Let’s start with this five-letter acronym for “PCS-type Certification Review Board.” Nested within this acronym is another acronym for “Personal Communications Service.” Surfing over to their home page, “Welcome to PTCRB,” one is confronted by more acronymia. (By the way, ‘ptcrb’ is not found in acronymia.com’s dictionary at this writing.) I tried unsuccessfully to find out the rules for “obtaining PTCRB Certification on a mobile device” because I couldn’t provide the required company website on the Registration Page.

RSE

This TLA stands for “Radiated Spurious Emissions.” RSE are(is?) at the crux of the PTCRB certification. Finding their source(s) and mitigating them is exactly like the other stuff I love to do. Except finding out the rules, which is exactly like the stuff I hate.

CTIA

Originally dubbed the “Cellular Telephone Industries Association,” but now calling themselves, “CTIA – The Wireless Association,” lets you browse their website. I found a Test Plan for Wireless Device Over-the-Air Performance there, but no mention of allowed RSE levels.

Time to change tactics… I decided to look at websites of companies who operate the equipment.

The Horn reflector antenna at Bell Telephone Laboratories in Holmdel, New Jersey (Wikipedia)

AT&T

Sometimes I forget all the great engineering that came out of the old Bell Telephone Laboratories. So it was great to find this App Note: Antenna Fundamentals. (Maybe I liked it so much because it was like an advertisement for what I am good at doing!) I especially liked this quote:

A failure to meet FCC regulations or PTCRB radiated-spurious-emissions-conformance requirements due to a level of harmonic energy generated by the device is often blamed on the antenna. In truth, the antenna can often influence the level of the harmonics but does not generate these signals. An antenna almost never has gain at the harmonics of the intended band of operation. Provided the radio has acceptable harmonic performance, excessive harmonic generation is typically an interaction between the impedance of the antenna and the impedance of the final stage of the transmitter.

−ATT Antenna Fundamentals – Technical Brief, p.  34

Heck, yeah!

This is a great Tech Brief, especially because it doesn’t push one type or brand of antenna over another, and it isn’t written to scare anybody into becoming a customer …but I still didn’t have my RSE answer.

ECN

(I don’t remember what the letters stand for, but it’s been a trade magazine for a long time. I emailed the editor, so maybe he’ll get back to me on this.) Bleary-eyed, I clicked on a link to their article, Cellular Carrier Certification Requirements and scanned down the page… Bingo!

Note that PTCRB limits follow ETSI limits, not FCC limits.

ETSI

(European Telecommunications Standards Institute) After all that, I really appreciated their website: The first link on their homepage was Standards. It still took a while to get to the right document, but at last I believed I had found it:

ETSI standard ETSI EN 301 502 V10.1.1 (2012-01)

Table 4.2.5-1: Spurious Emissions Measurements outside the transmit band

Band

Frequency offset outside

relevant transmit band

Maximum power limit

Multicarrier BTS

9 kHz to 1 GHz

≥ 2 MHz

≥ 5 MHz

≥ 10 MHz

-25 dBm

-20-4,2*(Δf-5) dBm

-36 dBm

1 GHz to 12,75 GHz

≥ 2 MHz

≥ 5 MHz

≥ 10 MHz

-25 dBm

-20-3*(Δf-5) dBm

-30 dBm

Just Wail

You’ve got to learn your instrument. Then, you practice, practice, practice. And then, when you finally get up there on the bandstand, forget all that and just wail.

Charlie Parker

I was called in to help on a design project to marry a cell phone with a portable medical device. As it usually happens, almost everything about the project is pretty well set in stone and the mortar is drying fast. Trouble is, the equipment failed the approval testing that it needs to be legal. (Sort of like when you car won’t pass inspection, except the inspection costs $20,000 …)

There is no time to design a new antenna for the device. I fired off an email to a buddy of mine who works at the company who made the antenna, and his antenna expert said, “Make the housing bigger.” (Sort of like when the Wizard of Oz told Dorothy, “Go see the Wicked Witch and ask her for her broomstick.”) This is one of those cases where the left brain just ain’t gonna cut it… So I took a stroll through the imaginary door into the world of ideas. What I came back with sort of resembles the ignominious “coat hanger antenna,” but actually has some theory behind it – it’s called a “coiled coax balun.” It’s almost free, and it worked for this project.

Stay ‘tuned’.

Brain Damage

I was doing my best to read Atlas Shrugged, because the book is in the news and mentioned by friends of mine. I tried, I really did, but I just couldn’t seem to connect with the story – I just felt I didn’t know any people who thought and acted like these characters and I could not suspend my disbelief.

Instead, I indulged in one of my favorite pastimes, reading about near-death experience (NDE).

There was another book being talked about, a new one, entitled, Proof of HeavenI pre-ordered the Kindle version and read it through in about a day-and-a-half. [Disclaimer: I have tried to link to op-ed pieces that distinctly disagree with my PoV hoping to enrich the dialog for you.] As I was reading Dr. Alexander’s description of his experience, it struck me how similar his word choices were to my attempts to describe the World of Ideas… 

I am aware of other PoV’s. That there is a religion gene. That spirituality is a mind virus. Scientists, by definition, do not have these kinds of thoughts; therefore people such as Drs. Alexander and Taylor have disqualified themselves as scientists. Clearly, there are people who think religious faith and spirituality are forms of brain damage.

Some of us think the opposite: To not perceive the spiritual portion of reality is akin to being color blind or tone deaf. Thankfully, it doesn’t last forever.

Nuggets from the World of Ideas

Once upon a time

There was a place where you could walk into a flowing stream, and if you knew what to look for, you could reach right down and pick up a piece of gold. I can imagine that copper, tin and iron once laid around in lumps.

In ancient Babylon and Sumer (and elsewhere) crude oil and tar flowed like springs up out of the ground.

Diamonds, rubies, emeralds, opals, turquoise, were all just pretty rocks…

…once upon a time.

Those days are pretty much all gone now, unless you count finding buried or sunken treasure.

…or are they?

The World of Ideas

Often in conversation, new friends will get around to asking me what I do. Or, knowing what I do, they will ask me how I do it. I have learned to pause for a second –or two– and look as if through an invisible door. In my imagination a metaphorical doorway from ‘our’ world to the world of ideas opens before me. Stepping through the doorway in my mind, I describe to them what I see.

Imagine a world where ideas lay around on the surface of the ground like rocks in a stream. You don’t even have to dig for them; you just have to meander around and notice.

“And I am not the only human being in that world,” I tell them, “Other people are there too, picking up ideas.

“Sometimes, I see people fighting over ‘big ideas’. I try to avoid those places. When somebody comes over and gets interested in taking over what I’m doing, I just give it to them and move on. I don’t want to get involved in a fight over one idea when so many of them are out there.”

Source: DC Animated Universe Wiki

Why Aren’t You Rich?

This is a natural question, I suppose, but one I didn’t think about before someone asked it the first time. It comes up a lot, though, apparently…

(Nygma discovers his office is locked and his nameplate is missing)
Edward Nygma: What’s going on here? Where’s my office? My door was right here.
Janitor: “Was” is right.
(Holds Nygma’s nameplate up and dumps it in the bin)
Edward Nygma: What’s the meaning of this?
Daniel Mockridge: What does it look like, Eddie? You’re out of here. You’re history. You’re fired. Comprende?
Edward Nygma: Have you lost what passes for your mind!? You can’t afford to do without me, Mockridge!
Daniel Mockridge: I can if you’re going to sue me for royalties.
Edward Nygma: I created the “Riddle of the Minotaur” game! This company’s making millions for my genius!
Daniel Mockridge: Competitron Software’s success didn’t come from the product, Nygma. Competitron has a corporate attitude. It’s strength is in the boardroom. The deal. The contract. Specifically the “Work for Hire” contract you signed.
(Shows Nygma a contract he tricked him into signing long ago)
Edward Nygma: You are a fool, Mockridge, if you think you can get away with this. Your amoral greed is no match for an intellect like mine!
Daniel Mockridge: Oh, yeah? Then tell me something, Eddie: if you’re so smart, why aren’t you rich?

DC Animated Universe Wiki

… so people ‘get’ the idea that cash follows creativity, but not necessarily in the same person. I feel like this– If I had to choose between pursuing ‘success’ or being able to go to that place, which would I choose? I guess the answer is obvious by now.

I’ve found myself feeling Edward Nygma’s pain a time or two, I won’t lie. But I learned there is more joy in going into that world than in fighting over who gets to bring an idea back from there.

The Wisdom of Crowds

Sir Francis Galton (Wikipedia)

Galton undoubtedly thought that the average guess of the group would be way off the mark. After all, mix a few very smart people with some mediocre people and a lot of dumb people, and it seems likely you’d end up with a dumb answer. But Galton was wrong. The crowd had guessed that the ox, after it had been slaughtered and dressed, would weigh 1,197 pounds. After it had been slaughtered and dressed, the ox weighed 1,198 pounds. In other words, the crowd’s judgement was essentially perfect. … Galton wrote later, “The result seems more creditable to the trustworthiness of a democratic judgement than might have been expected.” That was, to say the least, an understatement.

James Surowiecki, The Wisdom of Crowds

It’s crowded inside my head right now–

  • The national elections are coming up in November,
  • Some of my friends are predicting the end of the world as we know it,
  • We are experiencing a global energy transition,
  • We are trying to come to grips with the reality of climate change,
  • The universe is evolving toward infinite complexity,
  • We need to do something…

(One difference between me and my computer is that I can decided to jump outside of a problem without my computer thinking I am broken. I think I will do that now!)

I bought Surowiecki’s book, if not his argument. I think that strange things happen all the time in life, and while there is inescapable correctness in both democracy and the Iowa Electronic Markets, there are also brilliant flash-insights that go against the majority’s opinion.

Jumping out of jumping-out-of-the-problem, here are some interesting statistics that might seem unrelated to my list, or to ‘wisdom’. On one hand…

Americans’ self-reported church attendance has continued to inch up in 2010, with 43.1% of Americans reporting weekly or almost weekly attendance. This is up slightly from 42.8% in 2009 and 42.1% in 2008. The increase comes as Americans’ economic confidence has also risen, suggesting that, instead of church attendance rising when economic times get bad, as some theorize, the opposite pattern may be occurring.

—Frank Newport, Gallup

On the other hand…

Characterizations of religious life in the United States typically refererence poll data on church attendance. Consistently high levels of participation reported in these data suggest an exceptionally religious population, little affected by secularizing trends. This picture of vitality, however, contradicts other empirical evidence indicating declining strength among many religious institutions. Using a variety of data sources and data collection procedures, we estimate that church attendance rates for Protestants and Catholics are, in fact, approximately one-half the generally accepted levels.

—Hadaway, Marler and Chaves, What the Polls Don’t Show

“Secularizing trends?” You mean, like in science…

Source: Pew Research Center for the People & the Press

The recent survey of scientists tracks fairly closely with earlier polls that gauged scientists’ views on religion. The first of these was conducted in 1914 by Swiss-American psychologist James Leuba, who surveyed about 1,000 scientists in the United States to ask them about their views on God. Leuba found the scientific community equally divided, with 42% saying that they believed in a personal God and the same number saying they did not.

More than 80 years later, Edward Larson, a historian of science then teaching at the University of Georgia, recreated Leuba’s survey, asking the same number of scientists the exact same questions. To the surprise of many, Larson’s 1996 poll came up with similar results, finding that 40% of scientists believed in a personal God, while 45% said they did not. Other surveys of scientists have yielded roughly similar results.

—The Pew Forum, Scientists and Belief

(In the direction of peer pressure, and since science is a collegial enterprise, one could assume that the unbelieving group of scientists would not be truthful.)

  • As many as 51% of scientists believe a higher power exists in the universe.
  • As many as 20% of “regular citizens” do not attend church regularly, but do lie about it.
  • Fracking could replace global warming as the Next Big Thing Argument.
  • Whoever gets elected in November will very likely be the right candidate for the job.
  • The world as we know it is always ending. That’s a good thing, actually.
  • The universe is probably evolving exactly as it thinks it should.
  • We don’t need to do anything, but we get to, if we want.

What is ‘Truth’?

Picking up from here

 writes:

[Gödel] believed that mathematical objects, like numbers, were not human constructions but real things, as real as peanut butter sandwiches. …

If numbers are real things, independent of our minds, they don’t care whether or not we can define them; we apprehend them through some intuitive faculty whose nature remains a mystery. From this point of view, it’s not at all strange that the mathematics we do today is very much like the mathematics we’d be doing if Gödel had never knocked out the possibility of axiomatic foundations. For Gödel, axiomatic foundations, however useful, were never truly necessary in the first place.

Gödel didn’t prove numbers are “real things,” but by proving that there are true statements about numbers that cannot be proven, did he not  imply that numbers (and thus, possibly other things) exist apart from the human mind?

This is echoed in Ayn Rand‘s philosophy of Objectivism. Once again, however, something has been left out. This time, it’s Gödel’s incompleteness theorem— Objectivism seems to hold that:

  • Logic will eventually gather all the knowledge there is to gain, and
  • If it cannot be attained through logic, then the so-called ‘knowledge’ is not ‘real’, e.g. ‘knowledge’ gained through ‘faith’.

But if “no system of logical axioms can produce all truths about numbers because no system of logical axioms can pin down exactly what numbers are,” [Ellenberg] how, then, are those truths to be produced and pinned down, except by a rudimentary kind of faith? It is easy to forget that Pythagoreans were mystics who used mathematical ideas for religious purposes.

I found help in an essay by Princeton mathematician, Edward Nelson–

The notion of truth in mathematics is irrelevant to what mathematicians do, it is vague unless abstractly formalized, and it varies according to philosophical opinion. In short, it is formal abstraction masquerading as reality.

[‘Truth’] is a correspondence between a linguistic formulation and reality.

Abstract ideas [about truth] have concrete consequences– this is their power.

[Nelson, Mathematics and faith, in “The Human Search for Truth: Philosophy, Science, Theology – The Outlook for the Third Millennium,” International Conference on Science and Faith, The Vatican, 23-25 May 2000, St. Joseph’s University Press, Philadelphia, 2002.]

Perhaps the truth of mathematics is metaphorical. Perhaps the only way we can perceive truth is through metaphor. Perhaps the only way we can make the connection from metaphor to truth is to employ a kind of faith.

Gödel

Kurt Gödel (Wikipedia)

It’s easier to disregard someone when you leave them out. It’s easier to disregard ideas when we don’t think about them. We sometimes do this when faced with inconsistency don’t we?

Haven’t we learned that consistency is absolutely necessary in order to be logical?

To be logical is to be reasonable… Isn’t it therefore unreasonable to be inconsistent?

Although I am not a professional mathematician, I use mathematical concepts daily. Most of us think that mathematics is the epitome of logical thinking. Most of us would think that arithmetic –the “oldest and most elementary” kind of mathematics there is– has to be self-consistent, but this only turns out to be true so long as you assume arithmetic is self-consistent but don’t try to prove its self-consistency using arithmetical statements.

Officially,

[In] any consistent effective formal system that includes enough of the theory of the natural numbers …there are true statements expressible in its language that are unprovable.

Gödel’s first incompleteness theorem

But hang on a second, this is a theorem saying it is mathematically true that there are mathematically true statements that cannot be proven (or disproven) true mathematically!

Doesn’t that wreck mathematics?

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