Stevie Ray Vaughan's Copter Crash, 29 years ago today

Article over at This Day in Aviation.

Vaughn died, but Michael Jackson continued on for decades.  The world is not a fair place.

Metering Out the Mini W3EDP

Last spring at one of our ham campouts (read about it here), I was surprised that the 21' tall Mini W3EDP antenna I was using worked so well on 80 meters.  By all rights, it just shouldn't have been that good.  To get a little more understanding of this thing, I took an hour last weekend to hang it from a limb (well clear of the trunk and everything else) and look at what it's doing with an SWR, resistance, & reactance meter.

Resistance as measured here is essentially radiation resistance, i.e., electrical energy being converted into radio waves, while reactance is (being non-technical here) push-back from the antenna that looks like resistance but that doesn't contribute to sending radio waves.  The whole situation's complex.  (joke! you laugh now!)  Will call them R and X for the rest of this post.

First though, a description of the antenna.  Inspired by a design at thewakesileave.com, I built a slightly more robust antenna.  It consists of a 16.75' piece of 22 gauge wire (anything similar will do) soldered to one side of a 3.5' piece of 450 ohm window line.  Wait, cut it a few inches longer and tie to an insulator at the top.  Suitable lugs were added to the other end of the window line, which attaches to a 4:1 balun.  Be sure to hook the antenna leg to the "hot" side of the balun, and the short ladder-line only leg to the ground side.  (I'm using this LDG voltage balun, though this similar current balun is probably a marginally better choice.  Same price.  If I had to do it over again...  But either should work.  Or roll your own, it'll work too.)  A length of coax cable attaches to that, which goes to your antenna tuner.  Yes, this design requires a tuner.  At least the rest of the antenna is cheap.  I'd show a picture, but it's kind of a mess visually, and this description is even better if you're building one.

In actual use so far, I've hung a 17' ground wire off the HF radio (or SWR meter here).  Might do better on the low bands to hang a 34' wire as well, and let the radio waves figure out which path they want to take.

Back to the antenna testing.  Hung it from a tree limb with the balun near ground level.  Used a stake to keep the bottom end from swaying in the breeze.  Swept through each of the HF and adjacent ham bands (160 & 6m), and tabulated the R and X at the bottom and top of each band.  Whenever there's a pair of numbers, it's for the bottom–top of band.  Results and notes:

• 160m was hopeless, with sky-high SWR and R; X however was 0.  huh.
• 80m was OK.  SWR in the 7-ish range, R from 270–31 ohms, X 121–61.  Not ideal, but OK.
• 60m was a little better.  SWR 3.0–2.8 , R 25–6, X 21–19.  It'll sorta work.
• 40m much better.  SWR 2.0–1.6, R 114–59 ohms, and X = 0 across band.
• 30m is good, SWR 2.0–2.1, R 114–59, X 0–27.  Could work (barely) without a tuner.
• 20m is weird but good.  SWR 4.2–4.6, R 300-ish ohms, X = 0.
• 17m is OK.  Such a narrow band, just took 3 numbers: SWR 6.9, R 337, X 92
• 15m is great: SWR 2.0–1.7, R 25-ish ohms, X = 0.  This at least partially explains how I made that one voice contact to Washington state last WFD on just 5 watts.
• 12m will tune, but it's meh: SWR 3.1-ish, R 65-ish, X 53-ish.
• 10m is a little better: SWR 2.4–4.7, R 286–145, X 73 across the band.
• 6m is OK for the low parts of the band: SWR 2.4–4.7, R 144–129, X 0–104

Not too surprisingly, CB will work here too (still need the tuner), with SWR in the 5-ish range and X fairly low.  That's a nice bonus, and I'll have to try it out on a future campout.

I've seen various suggestions to hang the ground wire off the ground leg lug at the balun, so I tried these too.  In general, they gave similar but lower SWR and X values.  I suspect it was just some RF getting damped out on the ground, a net loss of radiated power.  I'll be grounding a the radio.

Anyway, yeah, it works!  At 21' total length, it's easy to hang in a tree.  (How many times have we seen people spend hours trying to hang something wondrous and complicated at a remote campsite?)  It does require a tuner and decent coax, but it works fine at QRP power up to at least a full hundred watts.  Is it the perfect antenna?  No, but none are.  What is surprising is that it performs fairly well all the way down to 80 meters.  It's a good antenna to get started on (cheap! DIY!), and a great antenna to take camping.

So what is this thing?  It's a Zepp.  It's a heavily adapted version of the original W3EDP.  It's a mini-G5RV with the ground arm chopped off, then hung up vertically by the remainder.  I wouldn't even want to see what an antenna modeling program would make of this thing. But most of all, what it is is something that works.

Anybody Missing a Mazda?

Following up on Wednesday's post, the NOLA S&WB extracted one of the cars on Thursday.  The Times-Picayune has pictures here, main story here, and commentary & speculation about what else could be in these canals here.

No owner has been identified as yet, but a vehicle inspection tag is dated 2007.  It's probably been there for a while.  To no one's surprise, Mardi Gras beads were also found in the wreckage.

Look closely at what's dangling from the trunk.

Scallops in St. Joe Bay

Not a lot to say, beyond that they're back in force and that it's easy to catch a limit.  Full article at the St. Joe Star.

No Wonder New Orleans Keeps Flooding...

Two cars found clogging up underground canal in Mid-City, over at NOLA.

It's going to be interesting when the NOPD runs the VIN numbers on these little bathtub corks.

Movie Review: Eye in the Sky -or- All Aboard the Trolly of Ethics

In our ongoing War on Terror (whatever you may think of the phrase), we've come across some interesting and deadly real-life problems that used to be largely theoretical.  With long duration drones we now have a god-like power to look down from the heavens and examine in real time what's happening on the ground, along with the ability to smite it with a thunderbolt as needed.  This movie is all about how this actually unfolds, from the spotters on the ground, to the military and political command structure overseeing things, down to the crew operating the drone.

Which brings us to The Trolly Problem.  Here it is in one picture and one paragraph:

Now, there are many variations on the basic problem, but in a nutshell it is this: Here comes the trolly, rolling straight along the tracks.  If the observer does nothing, five people will be run over (assume for this thought experiment that they somehow can't move off the tracks).  If however the observer throws the switch, only one person will be run over.  Which is the more ethical decision?  If the observer throws the switch, true, he has saved five people. However in doing this, he has also actively condemned a person to death.  If he doesn't throw the switch, he is not directly responsible for anyone's death, but he has knowingly left five people to die.  (Again, there are many variants on this basic problem, and you can read up on them at your leisure at Wikipedia.)  Note that there isn't a right or wrong answer to this problem, it's more of a thought experiment to tease out how we think about these matters, and to practice for when similar situations come up in real life.

Back to the case at hand, we have an estimated eighty people on the "do nothing" option track, with a half-dozen terrorists on the "fire the damn missile already" track.  Easy, right?  But it's only an estimated eighty people who will die.  Could be eight, could be eight hundred.  Could be zero.  And then there's collateral damage around the missile strike zone.  Innocent civilians wander on and off of that track.  Might be better just to scoop the terrorists up sometime later and milk them for intel... except that eighty people could die.  In the meantime politicians dither, jog people's elbows, and punt the ethical responsibility up the chain.  More information becomes available.  Situations develop.  And don't forget, there's a fifty four second flight time for the missile.  Lots can happen in fifty four seconds.  All while everybody at the switch gets. to. watch.

As far as the rest of the movie goes, it's top-notch.  Acting, sets, effects are all spot-on.  It is also notable that this is Alan Rickman's last film.  If there's any flaw in this this film, it's that the pacing is a little off.  Is this an action-suspense thriller, showing off the latest in spy and military hardware?  Yes, sort of.  Is this a philosophical exploration that takes its time in playing out the ethical discussion?  Yes, sort of that also.  Maybe in an opening scene, Rickman's character could have had a chat about coursework over breakfast with a college-aged daughter, and just happen to talk about the Trolly Problem.  This would better frame the situation for the audience, and set up the rest of the movie.  As it sits, it's kind of a mental DIY project that requires a couple of viewings to fit it all together, above the shock of the action, explosions, and deaths.

In the end though, it's a very good film.  Three out of four stars.

The Crazy Cat Lady of Fighter Jets

A French Chateau Hoarding the World's Largest Private Collection of Fighter Jets

"Hoarding" is the correct word here, though "scraps of aluminum that used to be major structural or exterior parts of fighter jets" is probably a more accurate description of that which is being hoarded.  None of these are likely to ever fly again, and it doesn't look as if there are any serious efforts at preservation being made.

As a side note, what is that V-tailed thing about a quarter-way through the article?