Tech Galavant

Here’s an idea on dealing with drones over your property, and learning about a simple radio signal jammer.

The increase of drones in our lives has raised some considerable concerns about invasion of privacy. There are some hobbyists out there who have no intention of violating people’s privacy, but then there are also some creepy folks out there who see this as a remote “peeping Tom” opportunity. I have a young daughter, and the thought of a drone creeping around her kind of — creeps me out!

It doesn’t seem like the laws right now are set to protect your privacy when it comes to what you consider is your airspace. You can’t shoot a drone down because that’s considered discharging a firearm in a place (that is not a shooting range, for insurance). But there has to be a way to protect your family from this kind of prowler nuisance.

As a Tech Galavant, that means coming up with a technological solution! When I was in the Army, I learned a little bit on the other intelligence disciplines including radio intercept and signal jamming. A drone is controlled remotely by radio signals, and so that got me thinking (a strange pastime indeed!) about what would happen if we could intercept or jam the radio signal. If the drone is providing a live video feed back to the remote, would the signal jammer be able to disrupt the video signal? Would the signal jammer cause the drone to fly orof course  come crashing to the ground? Could we intercept the radio signal and take over the controls?

Research

Radio signals operate on different frequency bands that have been regulated by the FCC. For instance, consumer radio devices can not operate on the same frequency band as a police or emergency band. You often see consumer products on the 2.4 GHz or 5 GHz spectrum. Military and emergency communications are on a different spectrum. The 5 GHz spectrum was basically opened up by the FCC for commercial use due to the congestion on the 2.4 GHz spectrum band.

Say what? Congestion? Think of it this way: put ten radios into a room and put them all on different radio stations. How difficult would it be to hear music clearly on just one radio station? That’s the same thing as congestion. There were so many commercial products introduced for cordless communication, it congested the spectrum and caused difficulty for consumers to communicate.

If you download a “Wi-Fi Analyzer” onto your smartphone, you can see examples of this in your own neighborhood.

Congestion interferes with the radio signal and causes it to diminish the effective range of communication (range = distance between two points, the sending signal device and the receiving signal device). It also slows down the speed at which the radio signal travels. Congestion is a basic concept behind interrupting the radio signal, and it’s very common already on the 2.4 GHz spectrum.

A key difference between 2.4 GHz and 5 GHz is the number of channels. It’s like having basic cable TV with only 11 TV stations vs. the extended TV service package which has 52 channels. Although 5 GHz has more channels, it’s still limited and can get congested.

Another key difference in radio signals is whether the signal was sent as analog or digital. Analog is ‘in the open’ or not encrypted. When cordless phones were first introduced, the phone conversations could be easily intercepted – all you needed was another cordless phone and you could listen to your neighbors phone conversations.

Digital signals essentially transmit 0’s and 1’s (‘binary’ format) over the same band, and do it discontinuously. Say what? Think of a train consisting of multiple train cars connected together. Each train car holds a sequence of numbers made up of 0’s and 1’s. Digital signals are like separated train cars that can reach the same destination independently. This makes the train cars reach their destination faster.

The same goes for the digital signal: not only is the message encrypted using 0’s and 1’s, but it also makes the signal travel faster between destinations.

Congestion can still be a problem for digital signals, though, and it’s amazing how many things can cause it: a lightbulb with high wattage, too many electronic devices in the same place, a microwave oven cooking popcorn, and the list goes on.

Discovery

I’ll just say that it’s amazingly simple to build a signal jammer and there are ample means of interrupting a radio signal on the internet. Radio signal jamming is prohibited by FCC regulation. The reason is that the same device which could be built to jam the drone’s signal could also be used to jam military or emergency communications.

Key Tech Galavant Rule: no breaking the law!

Now that I’ve learned this, I’m forced to find another way to prevent drones from creeping around my daughter. Perhaps I will stock up on some tennis balls (and potentially a tennis ball throwing machine!) to protect my family’s privacy.