Noted engineer and failure analyst Henry Petroski spoke recently as a part of the Design Matters series of lectures at UIUC. He has distilled millenia of human innovation into the following short sentences:
Perfection does not exist.
Form follows failure.
Criticism leads invention.
Design begets design.
Good betters best.
Problems persist.
Invention thrives.
Technology evolves.
I’m not sure there’s much I can possibly add to that…
Bargaining is one of the great lost arts among individuals. It is the process of arriving, quite literally, upon the actual value of an item or service. As I write this, it occurs to me that by shunning bargaining, stores have shifted that burden from the seller to the consumer…we now shop around. Would a bargain-based economy better for the environment? Anyhow, I digress…
I mentioned recently that I posted an old ThinkPad that I built from eBay parts on Craigslist. A (Vietnamese) woman very enthusiastically contacted me about it because her old ThinkPad of similar vintage had been recently broken by her daughter. This whole experience is probably worthy of a post in itself at some point. But, on the phone, she said, “I see you have ‘$45 or offer’ on the ad…how much you take for it?” Here, let me show you my cards so you know I’m bluffing. I told her that I had about $45 in the computer and would like to get that; but, she was free to offer me what it was worth. “Forty dollah, thirty-five dollah, thirty dollah?” she said. I told her I’d take $40 for it.
So, what’s wrong with this? Well, lots of things.
Maybe this is a cultural difference. But, I doubt it.
Anyone (does anyone actually read it with regularity?) who reads this blog is familiar with my rant about the “decline of the fundamentals.” Here is a story about a recent antenna project and how trying to circumvent the fundamentals came back to bite me…
One of the perennial problems for hams on small city lots (and worse, rental property) is the installation of effective HF antenna systems. My current lot is about 170’x 100’…substantial for a city lot. But, it has a 1500-sq-ft duplex plus a two-car garage. There are streets on two sides and the (above-ground) power line comes in from the corner opposite the streets. There are four large trees ranging from about 40-70 feet tall, approximately forming a 70-ft square (yes, I know 80-meter 4-square).
I recently installed a 40-meter dipole between two of the trees and an inverted-L for 160 meters between another pair. These were decent antennas, all things considered. I worked EU on 160 and could actually hold a frequency on 40 in the CW SS. I’ve had two 80-meter antennas since we moved here. The first was a killer…a 40-ft top-loaded vertical with lots of radials where the garden is now. But, the landlady and Sarah asked me (nicely) to remove my radials from their garden. So, I hastily errected a zig-zag dipole about 20-25 ft up between three of the trees.
Needless to say, I’ve never been real happy with the dipole. Furthermore, I only got four radials down this Fall for the inverted-L and the extras I laid on the grass sorta looked like a rat’s nest. I got to thinking…I don’t operate 160 that much. I had a rope in the pine tree at almost 60 ft for the inverted-L and I’d successfully shot a line into the big tree in the back corner to install my 40-meter dipole. I shot another line into the tree from the roof of the house. Great! I can put an 80-meter dipole at 60 feet!
The neurons kept firing…if I feed it with open wire, I can short the feeder and run it as a top-loaded vertical on 160. Brilliant. I can put the matching unit on the roof and use elevated radials (I can’t believe I’m saying this…but, it’s the only option for this installation) on 160. Dad gave me a roll of #14 THHN for Christmas (raw materials make the best presents). I went to a big box hardware store and picked-up the remaining parts for $15. I started cutting PVC pipe for spreaders with a hacksaw in the basement…hard work! Then, I remembered that the CubeSat shop is in the lab next to my office. A minute and a half with the bandsaw did what I spent a half hour on the day before. And, they looked better to boot. I built the antenna and hauled it into the trees.
Of course, using open-wire line, I had to do some matching. I measured the input impedance after the 1:1 balun (built with type-31 ferrite using a K9YC recipe) with my Autek VA-1. It’s L-network time! I figured there’s got to be an L-network calculator on the Internet that will save me a few minutes’ work. Indeed there is. I punched in the numbers and hit [calculate]. The component values seemed reasonable; so, I built it. Finding a coil form was a bit of a challenge. I have some Miniductor stock; but, nothing big enough. I tried a lot of things that I’m too sheepish to mention here before one day as I was leaving the office…I saw my coil form…lots of them piled-up against the instrument cases and cardboard boxes: poster tubes from conference travel. For good luck, I selected the three-inch tube that got stuck in the baggage handling system at O’Hare on the way home from Spring AGU in Acapulco… Actually, it gave me great pleasure to carve that up with the bandsaw.
I built the coil, added some capacitance, and triumphantly returned the relay/matching unit to the roof. I hooked-up the VA-1…and it was awful. The impedance wasn’t even close (it’s like 20-j200) to 50 ohms. I started clipping capacitors in parallel and it got worse. Then, I cut some off (the original design had three in parallel) and it’s got worse again. I’m up a creek! I went inside and had lunch. After eating, I carefully checked every joint and wire…good. So, I calculated the expected transformation given the parts. Hmmm…it gave me what I measured. I looked at the online calculator more carefully…
The calculator took the parallel equivalent circuit for the load, not the series equivalent circuit! I was in disbelief…who uses the parallel equivalent circuit unless they’re doing a calculation?! Apparently, the author did. Of course, it makes sense in retrospect…if I was writing an L-network calculator, this is the logical way to do it. I computed the parallel equivalent circuit, recalculated, and rebuilt. It hit almost dead-on 50 ohms.
It’s easy to see the lesson here: pay attention to details. But, perhaps the more important lesson is that the existence of ready-made design software does not justify ignorance of the fundamentals. Had I calculated the L-network by hand, I would have made the series-to-parallel transformation myself (or even better, let the VA-1 do it for me…wait, isn’t that how I got here?) as a part of the process. To quote the country song (out of context, of course), this was “time well-wasted.” I have a story to tell my students some day!
This analysis of a recent sporadic-E event came across the local ham club e-mail list:
http://www.swotrc.net/121607Es
I study the ionosphere “professionally” right now…so, of course, this piqued my interest. Although I’m an aeronomer, I’ll be the first to admit that the author probably has more experience with sporadic-E than I do. That said, I don’t completely believe him.
He presents several data sets, both from the MST (meso-,strato-,troposphere) region and the ionosphere. Given a lack of “activity” in the troposphere, he concluded that the sporadic-E was caused by a CME (coronal mass ejection) from the Sun. Why don’t I believe him? He invokes no physics (either through citation or explanation) to tie the CME to the formation of sporadic-E. Furthermore, also note by his own presented data that the effect of the CME wasn’t noted at SOHO and GOES until 0200 UT on the 17th, but the Millstone Hill ionosonde was seeing sporadic-E as early as 0000 UT.
The pressure to conclude something from data is immense. Perhaps the most admirable (and underrated) conclusion one can make from data is: I’ve noticed a correlation between X and Y. I believe that relationship X = F(Y) is responsible. I propose the following experiment to test that relationship…
Since I quit reading eHam due to the low SNR (signal-to-noise ratio), I’ve started reading news blog salon.com. Of course, whenever you enter a politically-charged environ such as Salon, you’re bound to encounter the same SNR problems as those elsewhere on the web.
In her piece Life Will Kill You, Katharine Mieszkowski writes
A cellphone is a microwave, and basically the reason your ear gets hot is that you’re warming it with a microwave.
Wrong! Your ear also gets hot because the phone is dissipating heat when it’s transmitting and because you’re trapping heat radiated by your body. My ear gets hot when I’m talking on a landline phone, too. Perhaps that should suggest something…
Do I believe that cell phone usage is 100% safe? No. But, I am concerned by the fact that people, especially in politics and the media, who have a tenuous grasp of science, are shaping policy opinions based on their junk science.
A project that my advisor and I are working on in South America got picked-up by the Weather Channel for a series about “extreme weather.” He showed me the broadcast recording (video file) of the story. The first thing I noticed when he played it was that the title at the bottom of the screen said, “Ionispheric Storms.” What? Yes, they spelled ionospheric wrong. “Well, that’s just a typo, ” you say. No, it is a failure of a system that is more interested in getting a story out than reporting something interesting or useful.
I’ve seen this sort of thing over and over on the War and Weapons Channel, the Discovery Channel, and others. I really can’t stand to watch TV shows about things that I’ve worked on these days because many of them are simply inaccurate. Why should I have reason to believe that the news or anything else is more accurate?
In a line of thinking I owe to statistician and information design expert Edward Tufte, real problems are messy and multivariate, rich and full of information and relationships. The more we learn about science, we should endeavor to make what we have learned more real, not more dilute. Everyone must know and learn more to do this. But, we will be rewarded for it.
I was reading E. Marla Felcher’s essay on Slate about making toys safer. She mentions a staggering statistic on defective toys: some 76% of recalls in the past twenty years have been attributed to “design flaws.” Perhaps toy designers should read Donald A. Norman’s The Psychology of Everyday Things. But, the part of the essay that got my attention was her discussion of difficulty of enforcement. This, essentially, is the difficulty with anything that is organized as a bureaucracy.
We know from high school government class that a bureaucracy is the “most efficient means to manage a large group of people.” However, the one thing that’s not often mentioned is the characteristic of bureaucracies that gives them such a bad reputation: it’s hard to get to the bottom of things. Multi-national corporations and militaries are built on the same bureaucratic structures. These structures are notoriously difficult to penetrate and affect from outside—is an action criminal or just following orders?
With a bureaucracy, we have “efficiency,” but at what cost? Perhaps outsourcing woes are a sign of things to come. Is it time for a new paradigm?
I was pondering my roots in electronic music last night after posting the Vocal Trance note. At first, I was tempted to say that the first electronic composition that mesmerized me was Enigma’s Sadeness, which I discovered quite by accident in 2001. But, upon further thought, I was mistaken. It was the Ray Lynch album Deep Breakfast. I have no idea where the tape came from, probably something that Mom or Dad heard on WKSU (the local NPR affiliate). I listened to the tape frequently as a kid (sometime around 1989, I’d guess), both in the car and the stereo at home; but, promptly lost interest. (Aside: I refused interest in all music for a period of a few years before discovering an interest in classic rock.)
I hadn’t thought of Ray Lynch in years. I couldn’t even remember his last name, although I do recall the genre classification from the cassette as “New Age.” I punched “Ray New Age” into iTunes and he popped right up. After listening to the first few bars of the preview clip for Celestial Soda Pop, I was able to hum the entire song to myself. The most remarkable things, though, were the dozen or so reviews repeating a story just like mine. They’d listened to Ray Lynch as a kid after their parents discovered his music in a gift shop or record store. According to his web site, Ray Lynch has never toured or performed on TV. Yet, he’s an extremely successful musician. The music sells itself. That’s a thought to consider all by itself…
I am reminded as I sit relaxing through two hours of Andy Gregory‘s tributes to Leama and Moor that vocal trance is essentially perfect music. The beat carries the energy. The melody carries the mood. It’s collage in sound. Everything is perfectly orchestrated. It’s a systems engineering approach to music. Beautiful.
The demolition-derby-monster-truck-madness-motorcross-tractor-pull-with-a-few-animals that is our county fair ended over the weekend. Since we’re travelling a little less now, too, I decided to fly the plane at the fairgrounds again last night. This is the first flight since the catestrophic wreck mentioned in the last post.
I walked out the front door and there were kids playing in the street. (When are there not kids playing in our street?) “He’s bringin’ that out to fly it!” one of them exclaimed. “Excuse me, are you gonna fly that plane right here in the street.”
“No, sorry, ” I said, “I’m going to the fairgrounds.”
“Awwww!” she said. At least somebody told them where they can and can’t go…and they’re still young enough to listen.
No worries for me…I’m still not quite good enough to fly with an audience.
I realized quickly that I’d hooked the controls up backwards during the repair. Fortunately, I was not yet “three mistakes high” and landed relatively easily. I reconnected the controls and had a pleasant evening of flying. I even managed some half-decent landings.
Flying takes a light touch. It’s a lot like driving a car in that a little correction can go a long way. What a great project!
For Sarah’s birthday, we went to see Allison Krauss and Union Station in Peoria last Friday. It was a very good show and we enjoyed ourselves, well, save for the fidgety enormous woman with enormous frizzy hair and meticulous posture who sat in front of Sarah until we traded seats. It was also pleasant to listen to well-mixed live music without ear plugs. All of the band members are characters and very good musicians in their own right. During the show, Dan Tyminski told an anecdote about being the singing voice of George Clooney in the movie Brother, Where Art Thou?
We were worn-out last night and decided to rent the movie (which neither of us had seen) and drink cream soda. It gets our highest recommendation. We’ve struck-out on a lot of recent movies, the last two being Babel and The Good Shepherd. By the way, both of these other movies were very well-done, just not particularly relaxing or satisfying for us. Brother was a different kind of movie…one we’ll look for more often when we just want to take a break from real-life and enjoy a good story.
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