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Comment Multiple antennas (Score 1) 105

They can take advantage of multiple antennas, directional antenntas, or both to lock onto the interference sources as well as the intended signal and use DSP to subtract out the noise and recover the original signal. Others have posted about how cellphones can take advantage of multipath interference to actually improve the received signal rather than degrade it. As long as the enemy is using a small number of stationary or slow-moving transmitters for their interference, you can locate them all and use DSP to remove the noise, OR if you can arrange for your signal to arrive from a different direction than the enemy's jamming just use a directional antenna. It would get more difficult if the enemy had hundreds of jamming transmitters moving around and covering your receiver from all directions. In the case of jamming a drone, your enemy would need either space-based jammers or airborne jammers to cover you from above. Space based jammers are impractical though (because of the distance) and airborne jammers are laughably easy to shoot down. It seems to me that the simple solution is to deliver your signals from above (satellites), use a directional antenna to ignore noise coming up from the ground, and then shoot anything out of the sky that makes noise which interferes with your signal.

Comment Another explanation (Score 5, Insightful) 911

Or maybe netbook sales are cratering because instead of delivering quality models with high performance and low power packed into a lightweight enclosure, companies like Dell have axed all but the most profitable models, and replaced SSDs with magnetic disks and raised prices to the maximum they can squeeze out of customers. Netbook selection is terrible now compared to what it was a year ago. Last year there were many models and there was a price war, now there are a few models and they're just crappy low-end notebooks.

Comment Tracking your TV watching is good (Score 3, Informative) 521

I can understand concerns about privacy when it comes to web browsing, but I don't get the fear about TV watching being tracked. I can't count the number of good TV shows that have been canceled because of bad ratings. Before Tivo existed, every time one of the shows I liked was canceled I wished that the TV network was tracking MY viewing habits instead of the unwashed masses who appear to like reality TV. Ever since I've had Tivo I always record all the shows I like and I'm happy that Tivo is collecting that information. Sometimes I even record and play back reruns (with the TV off) to positively affect the data for the shows I like.

Comment I rolled my own (Score 3, Interesting) 112

I have a 5 camera system (slowly growing) and I evaluated ZoneMinder and decided that it didn't meet my requirements, so I rolled my own. If you are good at C programming Linux has everything you need to write a simple capture/streaming application. I use USB video capture devices (Pinnacle Dazzle DVD Recorder) because they are cheap (no tuner), have excellent quality, and I have no shortage of USB ports.

Linux natively supports these devices, and the V4L2 APIs make it trivial to reads frames. Using libavcodec from the ffmpeg project you can encode the frames to practically any format imaginable. I encode all 5 cameras to MPEG-4 at 30 fps using minimal CPU power. All of this is possible with only about 500 lines of C code. Of course in my own version I've added a lot of fancy features over time and the project has gotten quite large with support for low-bandwidth streaming, crude motion detection, time-lapse video, etc.

I won't lie to you and tell you that the documentation for ffmpeg is any good. But there are tutorials out there that explain how to use libavcodec and everything else is a piece of cake. Don't overestimate how simple is it to get something basic working.

Hardware Hacking

Submission + - Hacking my UPS

Yossarian writes: "I have a 1300 VA (780 Watt) UPS that I use to power the servers in my house. With all the equipment I have plugged into it, it only lasts about 3 minutes in a power outage, which isn't long enough for me to get my backup generator started to keep things running. I had an idea that I could replace the 8.0 Ah batteries in the unit with a big 80 Ah Marine/RV deep cycle battery. In theory that should buy me closer to 30 minutes of backup time. However I'm wondering if the little 1 amp charger in the UPS will be able to charge such a large battery up to full charge (I realize it would be slow, but that's okay). I'm also wondering if the inverter in the UPS will be able to handle the increased run time. I know that many consumer grade UPSes have weak inverters that can barely handle their rated load, so running it 10 times as long as it was meant to run concerns me. Are there any other things I should be worried about?"

Comment No different from sales tax evasion (Score 4, Insightful) 451

Technically whenever you order a product from another state and the seller doesn't withhold sales tax on the purchase, you're required to pay that sales tax in your state. Nobody does this -- so technically nearly everyone is guilty of this kind of tax evasion. How is this any different?

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