brainwagon "There is much pleasure in useless knowledge." — Bertrand Russell

30Nov/081

Another Mandelbrot Zoom

Testing the Smart Youtube plugin for wordpress:

httpvh://www.youtube.com/watch?v=AdtOAOe1-qU

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30Nov/080

The Challenge of Amateur Radio

Jeff KE9V, over at KE9V.net is once again falling victim to pessimism about amateur radio. I can't help but shake my head at the effort that we as hams seem to put into lamenting the impending death of our hobby.

It's very strange. I can't think of another hobby that spends as much time as we seem to in the following three activities:

  1. Lamenting the impending doom of amateur radio, principally because so few newcomers enter the hobby, while simultaneously...
  2. Grouching that all the newcomers in the hobby are wrecking the hobby because of their lack of desire to do things the way what we all learned, and yet
  3. Spending all sorts of time trying to lure people into believing that our hobby is fun.

I prefer a different tactic.

If our hobby really was fun, we wouldn't need to work at recruiting people: they would just happen naturally. We couldn't keep them out of our hobby. If they don't think amateur radio is fun, it's probably best to assume that it's not fun, at least for them. Something about the way we present ham radio to them makes them believe it isn't fun. Many would argue that the man on the street just doesn't understand what fun amateur radio is, but I would submit that the average ham doesn't understand what fun is, or what the average young person would consider is fun.

Me? I just try to talk about the things which I think are fun, particularly things that can be done with minimal amounts of money and modest investment of time. I'll leave the anxiety of the future of the hobby to others. I'd rather just keep plodding along, doing what I like, and trying to engage targets of opportunity who read about what I like as often as I can.

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29Nov/080

Pico-Satellite Solar Cell Experiment (PSSC)

I just head that Endeavor will eject a small picosatellite (5x5x10 inches) that will test two different types of solar cells in the environment of space before it begins its deorbit maneuvers. I was interested in seeing if I could find any downlink frequencies for it, but haven't managed to do so. I did find the following NASA page:

NASA - Pico-Satellite Solar Cell Experiment (PSSC)

29Nov/080

Keyboard Acoustic Emanations Revisited

While my blog has been dominated by radio related stuff lately, I do continue to be interested in lots of different subjects, including various topics related to computer security and codes. While scanning my feeds today, I found reference to this work, which I hadn't seen before, but which I find interesting both for its security implications and its use of machine learning. Very cool.

Keyboard Acoustic Emanations Revisited

We examine the problem of keyboard acoustic emanations. We present a novel attack taking as input a 10-minute sound recording of a user typing English text using a keyboard, and then recovering up to 96% of typed characters. There is no need for a labeled training recording. Moreover the recognizer bootstrapped this way can even recognize random text such as passwords: In our experiments, 90% of 5-character random passwords using only letters can be generated in fewer than 20 attempts by an adversary; 80% of 10- character passwords can be generated in fewer than 75 attempts. Our attack uses the statistical constraints of the underlying content, English language, to reconstruct text from sound recordings without any labeled training data. The attack uses a combination of standard machine learning and speech recognition techniques, including cepstrum features, Hidden Markov Models, linear classification, and feedback-based incremental learning.

28Nov/082

Movie Review: Bolt, in 3D

Tonight I took my wife, son and future daughter-in-law out to see Bolt, Disney's newest animated feature. For extra bonus points, we went to go see it in 3D (yep, with the Real D glasses and everything).

I am somewhat skeptical about the long term viability of 3D. People seem to be highly variable in their reaction to the 3D experience: some people seem to find it hard to perceive any 3D at all, others seem to get headaches with even the most mild experience. I've rated my own reaction to be somewhat in between: I'm not immune to the eye strain, but I usually can tolerate it for a reasonable amount of time.

So, here's the good news: Bolt looks great! And it's a pretty nice family story too! Bolt is a cute young dog who is adopted by Penny. What Bolt doesn't know is that he's a TV star: he thinks he's a super hero protecting Penny from the evil Doctor Calico. When Penny is kidnapped in the cliffhanger episode for the season, Bolt inadvertently escapes, and embarks on a quest to save Penny from the Doctor's evil clutches.

The story is cute, the characters are cute, the jokes are funny, the look is amazing, there are some great action sequences (especially the first one): all in all, I think it's a pretty fun movie, and my family agreed. The audience in the theater I was in liked it a lot too: I heard laughter at frequent intervals, and spontaneous applause at the end of the film. See it in 2D if you must (or can't stomach 3D), but see it! It's just darned fun.

Obligatory disclaimer: I do work for Pixar Animation Studios, a division of Disney. I suppose if the film does well, it could have some positive affect on my salary, but I have a feeling you'd have more of an effect if you bought me coffee.

Addendum: Here's a clip from Youtube.

Filed under: Movie Review 2 Comments
27Nov/080

ATMega Controller

I've been playing around a little bit with the Arduino microcontroller board that I bought a while ago. It's a nice little board, but there are some alternatives that are also interesting, like the following board from Futurelec. It's got more I/O pins (lots more) than the Arduino, and is based on the ATMEGA128, with 128 megabytes of flash. Pretty nice, for < $30. ATMega Controller

27Nov/080

Changing my theme…

My WordPress "theme" seems to need a little maintenence. Don't be alarmed if the look of my website changes a bit over the next couple of days. I haven't upgraded it in a long time, and I'm trying to make sure it works with all the upgraded versions of WordPress that I've installed recently.

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27Nov/080

Happy Thanksgiving!

In my house, we celebrated the holiday yesterday, to give my son a chance to go and have Thanksgiving dinner with his in-laws. So I made a turkey, a ham, two pumpkin cheesecakes, potatoes, stuffing, a ratatouille, some gravy and a bunch of veggie appetizers. My future daughter-in-law made some green bean casserole. My wife made her famous yams. We ended up having fifteen or so people: more than any other time since we got married. A good time was had by all.

Here's hoping that wherever your Thanksgiving is, you and your love ones are healthy, and happy, and able to focus on the things which are good in your life. Best wishes!

Addendum: Here's the NOAA-17 pass that just happpened out over the Pacicific. Max elevation was around 32 degrees, so it's fairly short and noisy. Someday, I'll have to get a proper WXSAT antenna and receiver.



25Nov/084

You seem shorter than I remember…

When you get an amateur radio license, you are issued a callsign. Mine was KF6KYI. This was a "2x3" call, which means it had two digits, followed by a single region digit, followed by three letters. These are issued sequentially, which means they aren't particularly aesthetic or short. If you want to spend a grand $14, you can request a different (usually shorter, but sometimes with just some special meaning to you) callsign by the "vanity callsign program". The shortest "1x2" calls are fairly rare, so they actually have a kind of lottery system to reassign ones that have expired.

Net result: I am KF6KYI no longer.

I am now:

K6HX

Filed under: Amateur Radio 4 Comments
25Nov/080

NOAA 17 this morning…

My blog indicates that I was decoding my first NOAA weather sat images about a year ago. I have made some progress on improving the images that I get out, but not alot. Witness this morning's image, recorded beginning around 10:05 PST of NOAA 17 on 137.62 Mhz:

It seems pretty good, except for one thing: it is pretty hard to see what we are staring at underneath all the cloud cover. The bulk of the west coast should appear to the right of the midline of each image, and I suspect the visible portion covers roughly 45 degrees north to 20 or so degrees north at the bottom, but other than that, it's pretty hard to see any real detail. I have begun to plan my next revision of this program, which will record timing information as well, which will allow me to draw continent outlines over the map, which definitely will be helpful, particularly on the night time passes which use primarily IR imaging.

Addendum: With a bit of work, I can see the Great Salt Lake and Lake Tahoe. That, combined with my knowledge of the satellite orbit means that I can approximate the view with Google Earth:

It's only a rough approximation, but it should be reasonably close.

22Nov/081

New Morse Paddles

Today I had a few minutes to finally put together this pair of small Morse paddles that I got from American Morse. They have a very nice "milled aluminum" aesthetic that I like a lot. By themselves, they are a little light, and tend to float around a bit, but they include a tapped hole that can be used to secure them to a board. I'll probably use a little wooden plaque from a craft store, and mount my K1EL keyer on it as well to create a little mini Morse station that I can use with some of the QRP kits I'm building/planning to build. Or, I could simply hook it to my FT-817. It's got a built in keyer even. Not sure yet.


Addendum: I was still bored while waiting for my wife to show up, so I went ahead and soldered together my K1EL keyer kit, pictured to the right. I only had one real problem: the instructions claim that when you insert the battery, you should hear the dit dah dit (R) through the small builtin speaker. I didn't. I was confused. I checked the voltages between supply and ground. 3.2v, just as it should. The chip was getting power. I puzzled for a while, then suddenly realized there was a jumper that I needed to install to enable the small piezo speaker. Once I did that, all was well. Now, all I need is the proper cabling and a nice box (Altoids tin?) to mount it in, and I can use it with my new paddles.


Addendum2: Today I hacked a little 1/8" stereo cable and wired it up to match the requirements of my FT-817ND. I'm a complete rookie at this Morse stuff, but I thought I'd record a quick little video to show how it works, using my Canon digital camera. The audio on this thing is a bit weak, but you can get the picture. I had to hold the key down with one hand because otherwise it tends to walk around a bit, I have a block of wood that I'll eventually bolt it to.


Filed under: Amateur Radio 1 Comment
20Nov/081

Simple Mandelbrot Movie

I was bored. I had five minutes. I wrote some C code. A few minutes later, I had this movie.

YouTube - Simple Mandelbrot Movie


This is also the first time that I have tried to use the Youtube "annotation" functionality. Works pretty well. Wish I could overlay even a static, transparent image, similar to the YouTube logo that appears.

Filed under: General 1 Comment
20Nov/081

Holy Crap.

I'm really, really tired of watching the economy implode.

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19Nov/080

Grid Beam Building System

I ran across a reference to "grid beam construction". I didn't know what it was. Now I do, and it's kind of neat. Like a kind of Erector set technology for grownups.

Grid Beam Building System

(Heard about it from The Citizen Scientist)

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17Nov/081

Short Book Review: Hands-On Radio Experiments

I needed something to read on a plane trip this last weekend, and a quick stop at Ham Radio Outlet had me leaving with a copy of Hands-On Radio Experiments by Ward Silver, N0AX. Ward writes the "Hands-On" column each month in QST, and this book is nothing more than five years of his columns collected in one slim volume. If you have been an ARRL member and received QST for the last five years, you won't find anything new, but if you haven't (as I haven't) you'll find a bunch of neat articles, each one of which explains a short, concise bit of radio theory, accompanies by an experiment that you could run with a bare minimum of expense. I am looking forward to doing some of their oscillator and amplifier experiments. I recommend the book for someone who likes to learn things through experimentation.

Addendum: Some of the experiments do require equipment which the absolute beginner might not have (like an oscilloscope, which I still lack), but the majority can probably be done with a decent voltmeter.

Filed under: Amateur Radio 1 Comment