Building a Horn Antenna for Radar

So you’ve built yourself an awesome radar system but it’s not performing as well as you had hoped. You assume this may have something to do with the tin cans you are using for antennas. The obvious next step is to design and build a horn antenna spec’d to work for your radar system. [Henrik] did exactly this as a way to improve upon his frequency modulated continuous wave radar system.

To start out, [Henrik] designed the antenna using CST software, an electromagnetic simulation program intended for this type of work. His final design consists of a horn shape with a 100mm x 85mm aperture and a length of 90mm. The software simulation showed an expected gain of 14.4dB and a beam width of 35 degrees. His old cantennas only had about 6dB with a width of around 100 degrees.

The two-dimensional components of the antenna were all cut from sheet metal. These pieces were then welded together. [Henrik] admits that his precision may be off by as much as 2mm in some cases, which will affect the performance of the antenna. A sheet of metal was also placed between the two horns in order to reduce coupling between the antennas.

[Henrik] tested his new antenna in a local football field. He found that his real life antenna did not perform quite as well as the simulation. He was able to achieve about 10dB gain with a field width of 44 degrees. It’s still a vast improvement over the cantenna design.

If you haven’t given Radar a whirl yet, check out [Greg Charvat’s] words of encouragement and then dive right in!

Halloween props: The honking pumpkin

_honking_pumpkin (Custom)

We see a lot of Halloween projects attempt to scare people. Many of them work with the element of surprise, jumping or flashing lights when triggered. We’ve noticed though, people have come to expect those things. This project is a real sleeper. No one expects a couple car horns to blare in their face  when they push the pumpkin’s nose. We know it would make us jump. You can see it in action as well as get the entire circuit from his site. We doubt his neighbors will find it as amusing as we do.

[via Hacked Gadgets]

Fire Horn


Artist [Ariel Schlesinger] has managed to replace an air horn‘s compressed air tank with butane fuel. This hack manages to change the pitch of the horn slightly, as well as making one very noisy flamethrower. While not as impressive as other flamethrowers, this would probably take the cake for most achievable. Currently the site containing the how-to is down, but we would have to recommend not doing this at home anyway. Video after the jump.

Continue reading “Fire Horn”

iPod loaded horn boosts your tunes

Waveguide IPod dock

The Griffin AirCurve Dock is a nifty gadget that uses a coiled horn to increase the volume of your iPhone’s speaker. Griffin’s marketing claims that their passive device delivers “amazing amplification” and “you’ll swear there are full-sized speakers in there.” Meh. It does look like an interesting project for someone with a 3D printer. You could experiment with different passage and dock shapes. At least it gives us an excuse to post two massive DIY horns.

Continue reading “iPod loaded horn boosts your tunes”