Tuesday, October 20, 2015

Warner Bros. should hire this guy.


Look, I joke about my bike crashes and laboratory explosions, but in reality those are few and far between.  On the other hand this guy.... Put down your coffee and go watch.  No, really, put down the coffee and swallow.

I may have popped a stitch (yes, from a mountain biking injury) while watching.

Saturday, October 17, 2015

The quasi-Random Wire Antenna


These things are about the worst imaginable antenna that even begins to make sense, are big goofy fun, and work surprisingly well.  Here's the basic idea:

Just that easy.  Now, you will need a tuner to match the transceiver's expected 50 Ohms, and a very good ground to give this one-legged wonder something to "push" against, but beyond that it's stupid simple and free-as-in-beer cheap.

Now the question of "how long?" naturally arrises, and that's why this post refers to quasi-random.  (Not pseudo-random, that's something else entirely.)  I mean, if we're worried about the length at all, then it's not really random anymore.  But some lengths are known to be, if not exactly unworkable, really freekin' difficult.  Specifically these are at integer multiples of half-wavelengths of any frequency(ies) one might wish to use.  Electrically speaking, these are like trying to open a door by pushing on the hinge side.  So... just go through all the ham bands and eliminate these and you end up with a set of magic lengths that ought to generally work, if the minor deities of RF smile and a squirrel doesn't crap upon your handiwork.  Sounds like a lot of work, but fortunately for us all a really smart guy at the University of Delaware wrote a program to handle the grunt work, and he posted the results on the web right here.  In case that page ever goes away, here's the main result:
As usual, click to embiggen.  Lengths that are covered by the colored blocks are not so good.  Here is a color code to the bands:

A 136' hunk of wire works really well all the way down to 160m, but a 36' wire will give you everything you really need for 40m and above – and that's where the real action is anyway.  If you've got to do 80m NVIS as well, 71' will get it done.

Last Winter, I managed to work all over the Southeast and even out to California on 160m with one of these on only 100 Watts.  I started out with 36', but kept patching on more wire to add lower bands and didn't quit until I got to the bottom.  Kind of a sick looking antenna, all twisted together and wound around the yard.  Sure, it's wasn't the most efficient thing, but when a band opening occurs, usually almost anything that even sort of works is enough.  This evening before dark, I broke down and cut a nice piece of 12ga to 136'.  We'll see how it does in the next week or so.

If you're a new ham operator, you can learn an awful lot very quickly playing with one of these.  And if you're an experienced operator who, say, wants to have some kind of antenna to leave up at the hunting shack, beach cottage, or some convenient, RF-quiet spot in the woods, a random wire fills the bill.  Just remember, it will need a good ground.  RF burns are no fun.

Friday, October 16, 2015

"Where's the Flux?" Paper & Articles


First let me say that I don't think this is aliens.  But if a stray lottery ticket landed in your lap, wouldn't you go "hmmm" and check the numbers?  (No, you're not winning the lottery either.)  Anyway, here is the paper causing all the fuss, and two more accessible-yet-informative articles:
KIC 8462852 – Where's the flux?  Yes, they actually named a serious paper that.
Bad Astronomy's commentary – actually, a pretty good article.
The Atlantic weighs in.  One more for the liberal arts majors.

Wednesday, October 14, 2015

Movie Review: The Hobbit 3, Battle of Five Armies


As with part 2 of this series, it just wasn't that good.  Maybe  a little better than part 2, which in retrospect I'll demote to 2 out of 4 stars, and give this one a 2 also.  Again, the acting and effects were top-notch, but there was too much extra tacked on to bring things to the studio-demanded three movies.  "... thin, sort of stretched, like butter scraped over too much bread."

Let The Martian be your guide moviemakers: If you're starting with a well-known, well-regarded book, you'll probably make more money if you stay faithful to story.  Worked for LoTR, Harry Potter, and many others.  In contrast look at the film adaptations of I, Robot, World War Z, Starship Troopers, and the like.  Sure, they made some money, they didn't turn out to be juggernauts with decades-long sales tails like their source material.

Tuesday, October 13, 2015

Watch that Front Brake


Don't let it lock up.  Details in this oldie-but-goodie article at Dirt Rag.

Look, real physics with vectors and things!  And they got it right!

Monday, October 12, 2015

Happy Columbus Day


Seemed like a good day to go hit the woods.  Beautiful weather.

Saturday, October 10, 2015

Catching Up Around the House


Redecking the ramp into the garden shed was one of those jobs slated for last Fall that was sidetracked by an unfortunate fall.  Finally got to it this weekend, here are the results:
Couldn't get the grill in or out without two people, so there hasn't been a lot of grilling lately.  That will change come suppertime!