brainwagon

While searching for a link for my brother on building antennas for HDTV (you guys are all ready for the oncoming digital TV Apocalypse, aren’t you?) I found this interesting link on an antenna which seems very good, and suitable for amateur construction. Seems like I could use some of the 12 gauge wire I used to make my Cheap Yagi to make this antenna in an hour or so. Might be a fun experiment, although since I live at the bottom of a rather narrow valley, I doubt it will render hdtv service tenable at my current location.

The Gray-Hoverman Antenna For UHF Television Reception - Digital Home Canada.

Addendum: Here’s a link to the general dimensions for the single bay version. It’s got two layers: he first has a pair of zig zag elements, and the “reflectors” are 100mm behind. Should be quite simple to fabricate.

Okay, I hadn’t been doing any WSPR beacon operations since before Thanksgiving (which was also before my new callsign) and I was kind of bored today, so I dug out my power supply, tuner and interface and set my computer beaconing again on 30m. It’s a combination beacon: using WSPR above 10.140100, and a visual “MV” written as part of a sawtooth in the visual MEPT portion of the band (between 10.140000 and 10.140100 Mhz). Output power is about 4 watts, split between both signals.

I’d be interested in any reception reports.

Addendum: Click this link to examine the reception reports I’m getting via the automated WSPR logging.

Addendum²:

Today, on Jan 2, I got a reception report from W1BW, and I could faintly see my “MV” appearing on his grabber:

You can see his “flying W” very strongly, and if you stare really close (click on the smaller image) you can see my MV which looks like part of a sawtooth around 23:22 (and other places).

Addendum²: Alan, VA3STL in Ontario also noticed my signal on the 2nd. Here is his screen grab, showing both my MV and my MEPT signal.

I admit to a fascination with Scientific American. I used to have a couple of decades of the magazine which I kept mostly for the Mathematical Games and Amateur Scientist column. Project Gutenberg has begun to digitize some of the 19th century copies, which are mostly of historical interest, but still can be interesting. For instance, the following issue:

Scientific American Supplement, No. 647, May 26, 1888 by Various - Project Gutenberg.

contains an interesting article by James Wimshurst on static electricity generating machines.

Never seen one? Check out:

Well, 2008 had its moments, but I’m glad to kiss it goodbye. 2009, bring it on!

Tonight Carmen and I decided to stay in and cook: we made some New York steaks, some spinach salad with smoked salmon, and a ratatouille topped with puff pastry. Basically using some of the skills we acquired at our recent cooking class, and it worked out really good. I’m currently stuffed, and watching some movies.

I wish all my readers the best in the New Year!

I’m spending way too much time sitting around this morning, surfing the web. I’m gonna stop, but before I do, here’s a link to an interested TED talk about how statistics can be misused to mislead juries.

Thanks to KE9V for pointing me at this lecture by Randy Pausch:

I don’t know what rock I’ve been living under, but it’s a fabulous lecture. You can read more about Randy here. As the New Year approaches and some of us might be making resolutions, it’s definitely worth watching.

Okay, it’s not really a “kit”, it’s just some directions on how you can wire some commonly available gadgets (like a Nokia 6100 LCD panel or a piezo speaker) to an Arduino board and make a nice little demonstration board. Some good ideas in here.

Polyphemus Demonstration and Evaluation Kit | Popular Science.

Carmen and I have reached the point in our lives where buying stuff for each other at Christmas is kind of superfluous. Stuff we need, we already buy, and stuff we don’t need aren’t the greatest gifts. What’s really valuable is the time we spend together. Toward that end, my wife Carmen used her own creativity, and signed us both up for a cooking class at Kitchen on Fire, a little place next to Chez Pannisse in Berkeley.

From their website:

Founded in 2005 by seasoned restaurateur and author Olivier Said of Cesar and popular chef instructor and caterer Chef MikeC.of Party Lifestyle, Kitchen on Fire® is located in Berkeley’s Gourmet Ghetto. Kitchen on Fire® is located in the Epicurious Garden which is an expansion and continuation of the gourmet cuisine legacy started by Alice Waters at Chez Panisse more than 30 years ago. Our classes offer a range of real skills for entertaining from learning how to throw a party on a budget to uncovering the mysteries of baking the perfect chocolate chip cookie. We also offer kitchen design consulting, corporate teambuilding workshops, in-home classes, classes for kids , private parties and events.

Our class was entitled “A Chef’s New Years Feast”, and included:

• Spinach and Smoked Salmon Salad with Soft Cooked Egg, Radish, and Lemon Dill Dressing
• Winter Vegetable Tarte Tatin
• Truffled Three Cheese and Seasonal Mushroom Cheese Gratin
• Maple Glazed Ham with Root Vegetable Puree
• Spiced Poached Pears With Almond Brittle

The class was three hours, with the first spent just discussing the menu, and the last two hours spent prepping and eating the food. Each of the dishes was just a little bit more elegant than the version that I would attempt. I’ve done salmon and spinach salad, but typically don’t make my own dressing from scratch. Their vegetable Tarte Tatin was very similar to the ratatouille that I’ve made a few times, but over puff pastry dough. The gratin is dressed up mac and cheese (very tasty). The ham was cooked over a bed of apples, tangerines and oranges, and was scented nicely from the fruit. And the poached pears were awesome, served with a little almond brittle, some pomegranate molasses and a scoop of vanilla gelato.

We had a great time. The class wasn’t intimidating at all, and the resulting dishes were delish. We’ll probably go back for another class sometime in the future.

Here are some camera phone pics:

Okay, for every slobbery dog video I post, I promise to post something with a little more meat. My friend Tom is interested in all kinds of computer music and interface technologies, and no doubt, has already seen this controller. But just in case he hasn’t, here’s a really nifty controller, and even he has seen it before, the rest of you can be inspired by this home brew multitouch controller. Very nifty.

Intimate Control for Physical Modeling Synthesis.

Okay, I mostly don’t post pet videos on this blog, but sometimes, you just have to make an exception, like when someone decides to give a bean burrito to his dog.

Okay, you don’t really need to make an exception. But I did. What can I say, for some reason I never posted anything on Dec 29 before, so I need to do something.

Addendum: Yes, the title was supposed to bring up images similar to “man eating lion” or “woman eating cabbage”.

Laura Halliday mentioned this page on the QRP-L while discussing the innards of those Radio Shack “atomic clocks” that you can buy. Seems like there are some good links to helpful information regarding the time services provided by NIST via WWV.

NIST Time and Frequency Publication Database.

Addendum: Jim Miller, AC3BV gave this link on deconstructing a Sony WWVB clock. It included an external antenna/receiver combo, which output a 1hz pulse position modulated signal. Very interesting!

A couple of years ago, I blogged about H. E. Dudeney’s Amusements in Mathematics. Today, I noticed that Project Gutenberg had released a copy of The Canterbury Puzzles by Henry Ernest Dudeney - Project Gutenberg. This book has quite a few more nominally mathematical puzzles than its sibling. In particular, it introduces the game Kayles, which makes appearances in most of the books I have on combinatorial game theory such as Conway’s On Numbers and Games.

Addendum: Some information on strategy for Kayles can be found here.

Alex wasn’t the first to recommend this article on building a 80m transmitter from parts scavenged from a CFL bulb, but his link was enough for me to elevate it to front page status. It’s a fairly neat project: the 80m transmitter only requires a handful of additional components (most notably, a crystal, but also a cap or two for the output filter), and outputs 1.5 watts using a 24VDC supply. Be careful when building though: CFL bulbs contain mercury, and while I think you can be hysterical about such things, caution is warranted.

While browsing around at the airport before Christmas, I ran across this page by PE0FKO about his program IQRec.exe, which is used to record the quadrature outputs from a Software Defined Radio. It includes an example recording of nearly 30 minutes of the CQWPX contest recorded on 40m at 96khz. In theory, that means that it covers 96khz of spectrum, although in practice, it looks like a bit less, no doubt due to roll off because of antialiasing filters in the sound card. Here’s a picture of a short 20 second or so snippet of the recording:

The tuned frequency is centered in the middle: you can see that there are no signals at the very top or
bottom.

This is a very nice little test file, including literally dozens of signals. I’ll be experimenting with it more.

It’s been quite some time since I’ve bought a book about telescope making: I just have been more absorbed in the world of amateur radio lately. Still, on my trip to Portland, I noticed that James Daley had published a book on an unusual telescope: the Schupmann.

The Schupmann Telescope

The Schupmann is an unusual telescope in that it is a refracting telescope with nearly perfect correction for chromatic aberration without using any exotic glasses. The main objective lens is a simple single element lens, which has a considerable amount of chromatic aberration. To cancel out this aberration, the light path is passed through a Mangin mirror: a meniscus lens where the back surface is coated with a reflecting coating which turns it into a second surface mirror. By carefully balancing the power of each of these elements, you can cancel out the chromatic aberration of the main lens. It’s a remarkable design, and rather uncommon. The only one I had seen was Jerry Logan’s superb 7″ instrument at the Riverside Telescope Maker’s conference.

Here are some links to the associated patent:

LUDWIG SCHUPMANN - Google Patents.

LUDWIG SCHUPMANN LUDWIG SCHUPMANN