Live data from Hacker News

How to Make a Cantenna (2013)

jacobsalmela.com

1–10 of 35 posts

Re: How to Make a Cantenna (2013)

#2
Wavelength (mm) ≈ Velocity of wave (Mm/sec) / Frequency (GHz)

w = v / f

We know v will be 300 (rounded up based on the speed of light mentioned above). For f, we need to plug in the Wi-Fi frequency.

You could just use 2.4, but in order to be a little more accurate, we will use two more decimal places. For channel 6 in the 2.4GHz spectrum, we need to plug in 2.437. Solving for w yields ~123mm.

w = 300 Mm / 2.437 GHz w = 123.102175

Now that we know the (w)avelength for our radio (f)requency, we can begin calculating the dimensions of the can based on the guidelines mentioned previously.

Re: How to Make a Cantenna (2013)

#4
Built one of these back in 2007 to hook up to my WiFi card in the barracks in Japan. Hacked the card a bit to push the power higher than allowed (firmware) and pretty much had the best signal ever for internet, at the cost of everyone else near me. Note that the AP was about 20 feet from my window, so I was just trying to drown everyone else out, not extend my range.

Got some flak from my 1st Sergeant at the time, but that was about it. At least I could raid in WoW, unlike everyone else on that godawful WISP.

Re: How to Make a Cantenna (2013)

#6

Wavelength (mm) ≈ Velocity of wave (Mm/sec) / Frequency (GHz) w = v / f We know v will be 300 (rounded up based on the speed of light mentioned above). For f, we need to plug in the Wi-Fi frequency. You could just use 2.4, but in order to be a little more accurate, we will use two more decimal places. For channel 6 in the 2.4GHz spectrum, we need to plug in 2.437. Solving for w yields ~123mm. w = 300 Mm / 2.437 GHz w…

I know you quoted the article, but this equation

> w = 300 Mm / 2.437 GHz

Has the wrong unit for c, it's missing the "per second"

Re: How to Make a Cantenna (2013)

#10
post #3

Wow! We built that thing 22 years ago! Fun to see it pop up like this periodically. Here's a link to the 10th anniversary: https://makezine.com/article/home/food-beverage/pringles-can...

It’s kind of a trip seeing people noodling around with stuff I hacked together 20+ years ago showing up on the HN front page at the same time. i enjoy kismet.

Currently #27: The anatomy of a smart bulb https://news.ycombinator.com/item?id=37808230

The OG smart bulb I made back in March of 2003 https://web.archive.org/web/20090923154300/http://www.oreill...

Post reply on HN