20 GHz LNB Testing And Teardown

December 27, 2024 by Al Williams 10 Comments

Many things have combined to make very high-frequency RF gear much more common, cheaper, and better performing. Case in point: [dereksgc] is tearing apart a 20 GHz low-noise block (LNB). An LNB is a downconverter, and this one is used for some Irish satellite TV services.

The scale of everything matters when your wavelength is only 15 mm. The PCB is small and neatly laid out. There are two waveguides printed on the board, each feeding essentially identical parts of the PCB. Printed filters use little patterns on the board that have particular inductance and capacitance — no need for any components. Try doing that at 2 MHz!

The LNB is a single-band unit, so it only needs to worry about the two polarizations. However, [dereksgc] shows that some have multiple bands, which makes everything more complex. He also mentions that this LNB doesn’t use a PLL, and he’d like to find a replacement at this frequency that is a bit more modern.

After the teardown, it is time to test the device to see how it works. If you want to experiment at this frequency, you need special techniques. For example, we’ve seen people try to push solderless breadboards this high (spoiler: it isn’t easy). Maybe that’s why many people settle for modifying existing LNBs like this one.

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Do You Know Vail Code?

December 27, 2024 by Al Williams 26 Comments

We talk about Morse code, named after its inventor, Samuel Morse. However, maybe we should call it Vail code after Alfred Vail, who may be its real inventor. Haven’t heard of him? You aren’t alone. Yet he was behind the first telegraph key and improved other parts of the fledgling telegraph system.

The story starts in 1837 when Vail visited his old school, New York University, and attended one of Morse’s early telegraph experiments. His family owned Speedwell Ironworks, and he was an experienced machinist. Sensing an opportunity, he arranged with Morse to take a 25% interest in the technology, and in return, Vail would produce the necessary devices at the Ironworks. Vail split his interest with his brother George.

By 1838, a two-mile cable carried a signal from the Speedwell Ironworks. Morse and Vail demonstrated the system to President Van Buren and members of Congress. In 1844, Congress awarded Morse $30,000 to build a line from Washington to Baltimore. That was the same year Morse sent the famous message “What Hath God Wrought?” Who received and responded to that message? Alfred Vail.

The Original Telegraph

Telegraphs were first proposed in the late 1700s, using 26 wires, one for each letter of the alphabet. Later improvements by Wheatstone and Cooke reduced the number of wires to five, but that still wasn’t very practical.

Samuel Morse, an artist by trade, was convinced he could reduce the number of wires to one. By 1832, he had a crude prototype using a homemade battery and a relatively weak Sturgeon electromagnet.

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Minecraft In…COBOL?

December 27, 2024 by Al Williams 36 Comments

When you think of languages you might read about on Hackaday, COBOL probably isn’t one of them. The language is often considered mostly for business applications and legacy ones, at that. The thing is, there are a lot of legacy business applications out there, so there is still plenty of COBOL. Not only is it used, but it is still improved, too. So [Meyfa] wanted to set the record straight and created a Minecraft server called CobolCraft.

The system runs on GnuCOBOL and has only been tested on Linux. There are a few limitations, but nothing too serious. The most amazing thing? Apparently, [Meyfa] had no prior COBOL experience before starting this project!

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Stream Deck Plus Reverse Engineered

December 26, 2024 by Al Williams 6 Comments

[Den Delimarsky] had a Stream Deck and wanted to be free of the proprietary software, so he reverse-engineered it. Now, he has a Stream Deck Plus, and with the same desire, he reverse-engineered it as well.

The device has eight buttons, a narrow screen, and four encoder dials. The device looks like a generic HID device to the host machine, and once it has been configured, doesn’t need any special software to function. By configuring the device using the official software in a virtual machine under the watchful eye of Wireshark, it was possible to figure out how that initial setup worked and recreate it using a different software stack.

If you’ve never done this kind of thing before, there is a lot of information about how to find USB data and draw inferences from it. The buttons send messages when pressed, of course. But they also accept a message that tells them what to display on their tiny screen. The device screen itself isn’t very big at 800×100.

[Den] packages everything up in the DeckSurf SDK, an open source project that lets you control Stream Decks. So if you just want to control the Deck, you don’t need to know all these details. But, for us, that’s where the fun is.

Way back in 2015, we covered some guy who had sniffed out a USB signal generator. That was easy since it was a serial port. However, you can go pretty far down the rabbit hole.

Tech In Plain Sight: Incandescent Bulbs

December 26, 2024 by Al Williams 71 Comments

While they are dying out, you can still find incandescent bulbs. While these were once totally common, they’ve been largely replaced by LEDs and other lighting technology. However, you still see a number of them in special applications or older gear. If you are above a certain age, you might be surprised that youngsters may have never seen a standard incandescent lightbulb. Even so, the new bulbs are compatible with the old ones, so — mechanically, at least — the bulbs don’t look different on the outside.

You might have learned in school that Thomas Edison invented the light bulb, but the truth is much stranger (public domain)

It has been known for a long time that passing a current through a wire creates a glow. The problem is, the wire — the filament — would burn up quickly. The answer would be a combination of the right filament material and using an evacuated bulb to prevent the filament degrading. But it took over a century to get a commercially successful lightbulb.

We were all taught in school that Thomas Edison invented the light bulb, but the truth is much more complicated. You can go back to 1761 when Ebenezer Kinnersley first caused a wire to glow. Of course, wires would quickly burn up in the air. By the early 19th century, limelight was fairly common in theaters. Limelight — also known as the Drummond light — heated a piece of calcium oxide using a gas torch — not electric, but technically incandescence. Ships at sea and forts in the U.S. Civil War used limelights to illuminate targets and, supposedly, to blind enemy troops at night. Check out the video below to see what a limelight looks like.

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Tweezers Probe Reviewed

December 25, 2024 by Al Williams 6 Comments

Over the last few decades, electronic devices have drastically changed. Radios that once had point-to-point wiring gave way to printed circuit boards with through-hole parts, and now microscopic surface mount devices are the norm. But most of us still use probes that would have been just fine for a 1940s receiver. There are other options, of course. Among other things, you can now buy meters that have built-in tweezer probes. While not the first, the FNIRSI LCR-ST1 are affordable, and [TheHWcave] puts them to the test in the video below.

The tweezers come with two different pointy ends. It is more or less one of those testers that can identify and measure various components. Instead of the customary socket, this one has tweezer ends and, perhaps, a few extra functions.

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Pi’s Evil Twin Goes For Infinity

December 24, 2024 by Al Williams 37 Comments

Most people know about the numerical constant pi (or π, if you prefer). But did you know that pi has an evil twin represented by the symbol ϖ? As [John Carlos Baez] explains, it and its related functions are related to the lemniscate as pi relates to circles. What’s a lemniscate? That’s the proper name for the infinity sign (∞).

[John] shows how many of the same formulas for pi also work for the lemniscate constant (the name for ϖ). Some (as John calls them) “mutant” trig functions use the pi-like constant.

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