Fail of the Week: Tracking Meteors with Weather Radio

It’s not hard to detect meteors: go outside on a clear night in a dark place and you’re bound to see one eventually. But visible light detection is limiting, and knowing that meteors leave a trail of ions means radio detection is possible. That’s what’s behind this attempt to map meteor trails using broadcast signals, which so far hasn’t yielded great results.

Passing jet’s Doppler signature

The fact that meteor trails reflect radio signals is well-known; hams use “meteor bounce” to make long-distance contacts all the time. And using commercial FM broadcast signals to map meteor activity isn’t new, either — we’ve covered the “forward scattering” technique before. The technique requires tuning into a frequency used by a distant station but not a local one and waiting for a passing meteor to bounce the distant signal back to your SDR dongle. Capturing the waterfall display for later analysis should show characteristic patterns and give you an idea of where and when the meteor passed.

[Dave Venne] is an amateur astronomer who turns his eyes and ears to the heavens just to see what he can find. [Dave]’s problem is that the commercial FM band in the Minneapolis area that he calls home is crowded, to say the least. He hit upon the idea of using the National Weather Service weather radio broadcasts at around 160 MHz as a substitute. Sadly, all he managed to capture were passing airplanes with their characteristic Doppler shift; pretty cool in its own right, but not the desired result.

The comments in the RTL-SDR.com post on [Dave]’s attempt had a few ideas on where this went wrong and how to improve it, including the intriguing idea of using 60-meter ham band propagation beacons. Now it’s Hackaday’s turn: any ideas on how to fix [Dave]’s problem? Sound off in the comments below.

Put Plasma to Work with this Basic Toolkit

Fair warning: [Justin Atkin]’s video on how to make plasma, fusors, and magnetrons is a bit long. But it’s worth watching because he’s laying a foundation for a series of experiments with plasma, which looks like it will be a lot of fun.

After a nice primer on the physics of plasma, [Justin] goes into some detail about the basic tools of the trade: high voltage and high vacuum. A couple of scrap microwave oven transformers, a bridge rectifier, and a capacitor provide the 2000 volts DC output needed. It’s a workable setup, but we’ll take issue with the incredibly dangerous “scariac” autotransformer, popularized by [The King of Random]. It seems foolish to risk a painful death mixing water and line current when a 20-amp variac can be had for $100.

A decent vacuum pump will be needed too, of course; perhaps the money you can save by building your own Sprengel vacuum pump can be put toward the electrical budget. Vacuum chambers are cheap too — Mason jars with ground rims and holes drilled for accessories like spark plugs. Magnets mounted below one chamber formed a rudimentary magnetron, thankfully without the resonating cavities needed for producing microwaves. Another experiment attempted vapor deposition of titanium nitride.

It’s all pretty cool stuff, and we’re looking forward to more details and results. While we wait, feel free to check out the tons of plasma projects we’ve featured, from tiny plasma speakers to giant plasma tubes.

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