Steven S. Holland

So today, shortly after getting home from work, I heard some singing, some bells, and all sorts of banging on drums and whistles outside my building.  Due to the porch roof, I couldn’t see anything from my window, so I went downstairs to investigate more closely.  What I found was a group of men dressed in white, with bells, drums, and towels (or so they appeared) dancing right outside.   One of them spotted me, and came over and told me about their background.  Apparently, my building, The Perry, was once The Drake (which clarifies the graffiti down the block that says “save the drake”), which was apparently once a bar/brothel/hotel that was a pretty wild place to be back 30 years ago.  The guy told me all about the respectable first floor, which regularly rejected them, and the “rat hole” basement, which readily let them in, including - according to one of the dudes dancing - beer served in metal buckets.  These guys used to hang out at the Drake in the 60s/70s and have been doing the dancing ever since, which is a good 30 years, as one specified.  Specifically, every 7th Tuesday after Easter is “Drake Tuesday”, which they come and dance out in front of the building, on the porch, and in front of the “save the drake” graffiti.

One of the guys also mentioned that, in viewing this dance, I was granted 1 year and 1 day of good luck.  I’ll take it.

The dancing?  According to their website:

The Morris is a living tradition of ritual dance and music, whose origins are shrouded in mystery, not to mention antiquity. The dance comes from England where it has been danced for hundreds, perhaps thousands, of years. John of Gaunt is said by some to have brought the dance back from Saracen Spain where he had been crusading. Others believe its origins are pre-Christian, possibly Druidic, perhaps even pagan. Similar dances are found throughout Europe and the Near East. Believe what you will. Many theories exist and, for now, no one can prove you wrong.

Morris dancing was almost lost in England during the nineteenth century. The tradition nearly died along with many other old, community based customs during the Industrial Revolution. The most recent revival began in England in the early twentieth century with the work of collectors like Cecil Sharp. There are hundreds of Morris teams in England now and at least 100 in the U.S. and Canada as well as other parts of the world.

Here are some pictures I took:

The videos were way over the upload limits for this site, so I threw them up on youtube:

Here is what I first saw when I walked outside.

Then they headed up onto the porch!

The other day at work my monitors suddenly shut off.  The computer was still running, which is a good sign, and connecting one of the monitors to the motherboard’s video card (and seeing an image!) quickly showed this to be a failure of my primary video card.

So I harvested a video card from another computer and when I took the video card out of my computer I saw, to my surprise, this:

Four of the 1500uF caps have popped!

A web search showed that this was not an isolated failure - many of these cards have had caps exploding on them.

So Discovery Channel is finally doing the show they should have a long time ago: a show dedicated to high speed camera footage, called “Time Warp”.  I did mention a while back how amazing I find high speed camera footage.  Maybe they owe me royalties for the show idea?…(or rather that video I saw in grammar school where they showed ordinary things, like sneezes, a fly flapping it’s wing, etc, at high speed).  I definitely look forward to seeing this show.

EDIT:  turns out their site is full of videos already.  Take a look!

There is a joke, or saying, when it comes to designing an oscillator or amplifier:

“amplifiers oscillate, and oscillators amplify”

The statement describes the fact that, when attempting to design one, there are many pitfalls that cause you to have the other happen.  Usually when designing an amplifier oscillations are your enemy, and you tune them out with bypass capacitors and work to ensure the stability criteria is met.  When designing an oscillator, on the other hand, the circuit can readily swing into a stable state if you don’t have a very good design, and end up as just an amplifier.  Granted, with proper design and construction this is avoidable, but when you are building one for the first time or just quickly building one, this can happen.

I propose a similar saying for antenna design, although to make this work, i am going to use “radiator” instead of “antenna”:

“Radiators couple, and couplers radiate”

This only applies, really, to antennas with more than one port, and really can apply to any microwave circuit.  But this way the phrasing works out much better.  But basically says that usually when designing an antenna, you are battling this coupling between ports, trying to get efficient radiation.  Yet on the other hand, when designing a microwave circuit, one of your enemies becomes radiation, and you work to keep that to an absolute minimum, because unwanted radiation is unwanted loss.

One of my favorite things to point out to friends of mine is this fact:

Remember in Back to the Future (I, II, and III) Doc Brown used a “flux capacitor” to travel through time?  Well, what if I told you that every capacitor is a flux capacitor?

Well that’s true.   As a simple example, say I took a capacitor and hooked it up to a battery, as below.  Then I show the capacitor as two metal plates with electric field between them, and a surface “S” parallel to the two plates.

As this crude analysis points out, the flux is nonzero so long as the voltage across the capacitor - any capacitor  - is nonzero.

Movie fans will point out that this isn’t magnetic flux, to which I have two rebuttals:

1.) the movie never states whether Doc Brown means electric or magnetic flux

2.) fine, you want a magnetic flux capacitor?  I give you, the mystical LC network - the transmission line stub, the antenna, the cavity resonator…etc.

Sorry Robert Zemeckis.

I need to take some time to find a good plugin and get this site setup so that spam comments are reduced — I am getting upwards of 10 spam comments a day at this point — but until then I am shutting them all off.  Currently I don’t even look through the comments in the moderation queue so I don’t want someone to post a comment and then it get buried in the spam noise.  So, if you have commented in the last few months, and it never showed up…this is likely why.

Every now and then I write or modify a matlab function that I need for my research, and will post them to this blog here and there, with the hopes that they will be useful to someone doing antenna/microwave design.  I know, there is the Matlab File Exchange (which is very useful!) , but hey, this is my blog, I want to post my content here.

Below is a function I used to plot smith chart results in matlab.  I used basic plotting code to generate the chart itself, and added a simply plot function to add the impedance locus and constant VSWR circles.  Hope this is helpeful!  Please let me know if anyone finds a bug.  I will note that there is no safeguard in the function for s-parameters that are greater than 1, which if you are plotting the active S-parameters of a multiport device, are possible.  This isn’t a big deal when the S-parameter goes slightly above 1, but if it swings well above 1 you end up with a tiny smith chart and these erratic line segments…it’s a mess.  For passive applications I haven’t come across a bug yet.

smithchart.m

This article from NASA talks about the measurement of magentic portals that connect the earth to the sun every 8 minutes, due to their magnetic fields pushing against each other and forming connections.  It is always interesting to see something happening on a such a large scale and with these huge fields that, as the article points out, many people didn’t believe in only 10 years ago.
I find the interaction of the electromagnetic waves on the scale of the solar system, between immensely large objects (here the earth and the sun) to be fascinating.  I spend so much time dealing with such small scale fields - antennas, microwave circuits, where fields are coerced into existence in these carefully designed structures to behave in a certain way.  Then I read articles on fields stretching 100 million miles between the earth and the sun, or the various effects the sun’s fields have on the earth, such as solar flares - fields covering half our solar system, in unbounded space, whose origins are not always clear or understood.  I mean, the earth’s magnetic field seems such a simple field that we take for granted - yet why it exists in the first place is not fully understood - you can’t exactly cut the earth in half and take a peak at it’s cross-section. It has even been shown to have flipped thousands of times over it’s lifetime - also something that we don’t quite understand the reason for.

I only have one course this semester, focusing on my Probability and Random Processes course and doing research.  This is by design, since I knew probability is a course I haven’t taken in 6+ years now…and I am super rusty.  But I have our text for the class, the schaum’s outline, and 3 other probability and random processes texts, and have been reading like crazy this semester, and doing sample problems out of the 4 texts and schaum’s.  Daily.  It’s good because I am having a much better time with this material than I expected, although the homeworks have been taking a long time to complete.

All this being said, here’s a sign it’s really starting to mess with my life: when I woke up this morning I asked myself what the probability of me getting out of bed when my snooze alarm went off for a third time (it’s set for 10 min intervals).  So I told myself, given how freezing it was in my apartment, and that I didn’t feel particularly awake, that I’d rate the likelihood of me getting out of bed on a given snooze alarm as 2/5, assuming I feel the same way independant of which snooze alarm is going off.

SO to get out of bed at the third snooze would be the probability of 2 failures to get out of bed, again assuming independence to make my just woken life easier, and one success:

P(I get out of bed on third snooze) =  (1-P(I get out of bed on first snooze))*(1-P(I get out of bed on second snooze))*P(I get out of bed on third snooze) = (1-2/5)(1-2/5)(2/5) = 18/125 ~ 20/120 = 1/6 ~slightly below 0.2, I’d say around 0.18 = => 18%

Then I went to sleep again and got out of bed on the 4th snooze alarm.

btw: The probability of me ever getting out of bed on my snooze alarm, found by summing over all probabilities from 1 alarm going off to infinitely many snooze alarm events, is 1, as you’d expect.  So it was bound to happen, eventually…

After spending most of the season in first place, it was looking dicey as it wore down and they slipped into 2nd place last week… but they pulled it off tonight!  Although I would have rather went to the game (as most of my family and friends got some of the tickets for tonights game….man!) than watch in the local bar ( I don’t have cable…) with a bunch of people rooting for minnesota to win, it was a great game.  I listened to half of the game online (it’s the only cheap way to get most their games, having lived outside of chicago for 6+ years now…), and then decided that this wasn’t doing it service, and of course it was on national TV tonight.  Thursday is going to be an interesting day — 1st playoff game vs. Tampa Bay, and the VP debate!