WEBVTT 00:00:00.000 --> 00:00:03.319 I want you to picture Times Square, specifically 00:00:03.319 --> 00:00:06.820 on New Year's Eve. Just imagine that shoulder 00:00:06.820 --> 00:00:11.480 to shoulder crowd. the chaos, the energy. Thoughts 00:00:11.480 --> 00:00:13.679 and noise. Right. Now imagine every single person 00:00:13.679 --> 00:00:16.120 in that massive crowd is screaming a completely 00:00:16.120 --> 00:00:17.960 different conversation at the top of their lungs 00:00:17.960 --> 00:00:20.960 all at the exact same time. And amidst that deafening 00:00:20.960 --> 00:00:23.839 roar, you are tasked with finding one specific 00:00:23.839 --> 00:00:27.179 person who is whispering a secret code. Exactly. 00:00:27.359 --> 00:00:29.179 That is, I mean, that is the reality of the air 00:00:29.179 --> 00:00:30.960 around us right now. We walk through it every 00:00:30.960 --> 00:00:33.560 day thinking it's just empty space. But it isn't. 00:00:33.659 --> 00:00:36.219 No, it really isn't. If you could somehow switch 00:00:36.219 --> 00:00:39.539 your eyes to see radio you would be blinded instantly. 00:00:39.899 --> 00:00:43.320 We are swimming in this chaotic ocean of Wi -Fi 00:00:43.320 --> 00:00:46.159 cellular data, Bluetooth handshakes, emergency 00:00:46.159 --> 00:00:49.200 dispatch frequencies, microwave radiation. Yeah, 00:00:49.320 --> 00:00:51.899 all of it. So today we are doing a deep dive 00:00:51.899 --> 00:00:54.899 into the invisible world, specifically the tools 00:00:54.899 --> 00:00:57.320 and the methods used to keep that chaos from 00:00:57.320 --> 00:00:59.719 just collapsing into total anarchy. Which it 00:00:59.719 --> 00:01:02.079 absolutely would without proper management. Right. 00:01:02.299 --> 00:01:04.840 We are talking about the radio frequency sweep, 00:01:05.140 --> 00:01:08.180 the RF sweep. And we're basing this on a technical 00:01:08.180 --> 00:01:10.540 overview of RF sweeps that covers everything 00:01:10.540 --> 00:01:13.879 from the core mechanics to real world applications. 00:01:14.120 --> 00:01:16.780 It's a fascinating document. It really is. Because 00:01:16.780 --> 00:01:19.239 our mission today is to understand how we manage 00:01:19.239 --> 00:01:22.040 this invisible traffic, from preventing interference 00:01:22.040 --> 00:01:24.219 at massive sporting events like the Super Bowl 00:01:24.219 --> 00:01:27.040 to finding corporate spy bugs. It's basically 00:01:27.040 --> 00:01:29.040 the story of how we visualize the invisible. 00:01:29.180 --> 00:01:31.640 Let's start right there. How do we actually see 00:01:31.640 --> 00:01:33.840 these invisible signals? Because, well, scanning 00:01:33.840 --> 00:01:36.750 sounds kind of passive, like taking photos. Right, 00:01:36.829 --> 00:01:39.030 but an RF sweep is a lot more active than that. 00:01:39.590 --> 00:01:42.450 The fundamental concept involves a radio receiver, 00:01:42.909 --> 00:01:45.450 but not like the one in your car. Because a car 00:01:45.450 --> 00:01:48.549 radio just sits on one station. Exactly. You 00:01:48.549 --> 00:01:51.989 tune to 101 .5 FM and it locks in. To do a sweep, 00:01:52.329 --> 00:01:54.250 you use a receiver with an adjustable receiving 00:01:54.250 --> 00:01:57.129 frequency. It continuously changes its frequency 00:01:57.129 --> 00:01:59.609 of operation, moving from a minimum frequency 00:01:59.609 --> 00:02:02.189 up to a maximum, or vice versa. It's sliding 00:02:02.189 --> 00:02:05.310 across the dial. Constantly. And the primary 00:02:05.310 --> 00:02:08.090 tool we use for this is called a spectrum analyzer. 00:02:08.509 --> 00:02:10.770 That is the standard instrument for an RF sweep. 00:02:11.030 --> 00:02:13.770 A spectrum analyzer. Yeah. It contains an electronically 00:02:13.770 --> 00:02:16.569 tunable receiver and a display screen. So as 00:02:16.569 --> 00:02:18.930 it sweeps across that band, it's measuring the 00:02:18.930 --> 00:02:22.389 amplitude, the power of any signal it encounters 00:02:22.389 --> 00:02:24.969 along the way. But the sliding across the dial, 00:02:25.030 --> 00:02:27.270 it isn't just random, right? No, no. It happens 00:02:27.270 --> 00:02:30.210 at a very fixed controllable rate. Because the 00:02:30.210 --> 00:02:32.449 source document mentioned a specific rate, something 00:02:32.449 --> 00:02:35.650 like 5 MHz per second. Yeah, 5 MHz per sec is 00:02:35.650 --> 00:02:38.210 a common example of a thorough sweep. And that 00:02:38.210 --> 00:02:40.310 rate is crucial because of the physics involved. 00:02:40.789 --> 00:02:42.569 You can't just snap your fingers and instantly 00:02:42.569 --> 00:02:44.449 capture the whole spectrum with perfect clarity. 00:02:44.629 --> 00:02:47.189 There's a tradeoff. Always a tradeoff. It's the 00:02:47.189 --> 00:02:49.729 balance between sweep rate and resolution. If 00:02:49.729 --> 00:02:51.990 you sweep too fast, you don't give the receiver 00:02:51.990 --> 00:02:54.750 enough time to accurately measure the power at 00:02:54.750 --> 00:02:57.639 each specific frequency. The data gets blurry. 00:02:57.939 --> 00:02:59.620 Blurry is a good way to put it. You miss the 00:02:59.620 --> 00:03:02.479 fine details. But if you sweep too slow, you 00:03:02.479 --> 00:03:04.580 might miss a signal that only transmits for a 00:03:04.580 --> 00:03:07.080 split second. OK. Let's talk about how the operator 00:03:07.080 --> 00:03:09.860 actually looks at this data. The display on the 00:03:09.860 --> 00:03:11.979 spectrum analyzer. It's a two -dimensional graph, 00:03:11.979 --> 00:03:13.860 right? Correct. We call it the power spectrum 00:03:13.860 --> 00:03:15.900 display. So what are we looking at? The x -axis 00:03:15.900 --> 00:03:18.159 across the bottom. That's frequency. Yes. The 00:03:18.159 --> 00:03:20.280 x -axis is the frequency band you are sweeping. 00:03:20.979 --> 00:03:24.110 Say... 500 megahertz to 1 ,000 megahertz. And 00:03:24.110 --> 00:03:26.969 the y -axis going up the side is the measured 00:03:26.969 --> 00:03:30.129 power. Now, here is where the source got into 00:03:30.129 --> 00:03:32.330 a technical nuance that I found really interesting. 00:03:32.669 --> 00:03:36.210 The y -axis, it's not a standard linear scale 00:03:36.210 --> 00:03:39.569 like a ruler? Usually no. You can display power 00:03:39.569 --> 00:03:42.710 in linear units like watts or milliwatts. But 00:03:42.710 --> 00:03:46.110 in practice, engineers almost always use logarithmic 00:03:46.110 --> 00:03:49.939 units. Specifically, dBm decibels relative to 00:03:49.939 --> 00:03:52.400 a milliwatt. Why is that? Why complicate it with 00:03:52.400 --> 00:03:54.419 logarithms? Because the difference between a 00:03:54.419 --> 00:03:56.819 strong radio signal and a weak one is astronomical. 00:03:57.000 --> 00:03:59.900 It's a massive dynamic range. I mean, how massive? 00:03:59.919 --> 00:04:02.379 Think about a local TV broadcast tower blasting 00:04:02.379 --> 00:04:04.860 out signal versus a tiny little Wi -Fi router 00:04:04.860 --> 00:04:07.219 two rooms over. The TV tower might be putting 00:04:07.219 --> 00:04:09.680 out millions of times more power. Okay. If you 00:04:09.680 --> 00:04:12.780 put that on a linear graph, the TV signal would 00:04:12.780 --> 00:04:14.680 shoot right off the top of the screen and the 00:04:14.680 --> 00:04:17.589 Wi -Fi signal would be a microscopic bump. flat 00:04:17.589 --> 00:04:19.329 against the bottom. You wouldn't even be able 00:04:19.329 --> 00:04:21.490 to see it. The strong signal just completely 00:04:21.490 --> 00:04:24.610 dorks the weak one. Exactly. But a logarithmic 00:04:24.610 --> 00:04:28.269 display compresses that visual data. It allows 00:04:28.269 --> 00:04:31.389 you to see the giant TV tower and the faint Wi 00:04:31.389 --> 00:04:34.529 -Fi signal on the exact same screen with great 00:04:34.529 --> 00:04:37.129 detail. It lets you see the whisper right next 00:04:37.129 --> 00:04:40.209 to the shouting. That's a perfect analogy. And 00:04:40.209 --> 00:04:42.430 you need to see the whispers, because at the 00:04:42.430 --> 00:04:44.310 very bottom of that display is something called 00:04:44.310 --> 00:04:46.629 the noise floor. The background radiation of 00:04:46.629 --> 00:04:49.089 the universe? Thermal noise, cosmic radiation, 00:04:49.430 --> 00:04:52.170 just general electronic leakage. And on a log 00:04:52.170 --> 00:04:54.370 scale, the noise floor isn't a flat zero. It 00:04:54.370 --> 00:04:57.110 looks jagged, like grass growing at the bottom 00:04:57.110 --> 00:04:59.009 of the screen. And the whispers hide in the grass. 00:04:59.110 --> 00:05:01.610 We absolutely do. So we have the spectrum analyzer. 00:05:01.790 --> 00:05:03.970 We know how it sweeps and how it visualizes the 00:05:03.970 --> 00:05:06.470 data. Let's talk about the applications. Who 00:05:06.470 --> 00:05:09.009 is actually out there doing this? The biggest 00:05:09.009 --> 00:05:11.589 players are regulatory agencies. They act as 00:05:11.589 --> 00:05:13.930 the traffic cops of the airwaves. Like the FCC 00:05:13.930 --> 00:05:16.509 in the United States. Exactly. The Federal Communications 00:05:16.509 --> 00:05:20.009 Commission. The radio spectrum is a finite resource. 00:05:20.670 --> 00:05:24.060 It's extremely valuable real estate. companies 00:05:24.060 --> 00:05:26.860 pay billions for specific slices of it. For cell 00:05:26.860 --> 00:05:29.500 networks, TV, emergency services. Right. And 00:05:29.500 --> 00:05:32.300 when you buy a license from the FCC, you are 00:05:32.300 --> 00:05:34.899 buying the exclusive right to transmit on that 00:05:34.899 --> 00:05:37.860 specific frequency in a specific area. So what 00:05:37.860 --> 00:05:41.180 does the FCC use the sweep for? To catch spectral 00:05:41.180 --> 00:05:43.879 squatters. They drive around in mobile monitoring 00:05:43.879 --> 00:05:46.740 vehicles equipped with spectrum analyzers, constantly 00:05:46.740 --> 00:05:49.060 sweeping the bands. They want to ensure that 00:05:49.060 --> 00:05:51.060 users are only transmitting according to their 00:05:51.060 --> 00:05:53.360 specific licenses. Making sure nobody is stepping 00:05:53.360 --> 00:05:56.259 on anyone else's toes. Because if an unlicensed 00:05:56.259 --> 00:05:59.199 pirate radio station, or even just malfunctioning 00:05:59.199 --> 00:06:01.639 industrial equipment, starts bleeding over into 00:06:01.639 --> 00:06:04.519 the frequency used by air traffic control. Planes 00:06:04.519 --> 00:06:06.879 can't talk to the tower. That's a massive safety 00:06:06.879 --> 00:06:09.639 hazard. It's life or death in some cases. Which 00:06:09.639 --> 00:06:11.779 is why regulatory monitoring is so strict. But 00:06:11.779 --> 00:06:14.379 it's not just the government doing this. The 00:06:14.379 --> 00:06:17.120 source material also talked about consumer electronics. 00:06:17.470 --> 00:06:20.470 testing new tech. Oh, definitely. Before any 00:06:20.470 --> 00:06:23.670 electronic device hits the shelves, your laptop, 00:06:24.050 --> 00:06:27.430 your smart TV, your garage door opener, it goes 00:06:27.430 --> 00:06:30.029 through rigorous frequency sweeps in an engineering 00:06:30.029 --> 00:06:32.860 lab. What are the engineers looking for? Because 00:06:32.860 --> 00:06:36.199 my laptop is in a radio station. But it generates 00:06:36.199 --> 00:06:39.420 radio frequency energy internally. The processors, 00:06:39.639 --> 00:06:42.500 the RF oscillators, they can leak. Engineers 00:06:42.500 --> 00:06:45.379 sweep the devices to check for specific technical 00:06:45.379 --> 00:06:48.639 issues. Things like phase noise, harmonics, and 00:06:48.639 --> 00:06:51.160 spurious signals. Spurious signals. Yeah, we 00:06:51.160 --> 00:06:53.800 often just call them spurs. It's basically electronic 00:06:53.800 --> 00:06:56.629 pollution. So a device might be designed to operate 00:06:56.629 --> 00:06:59.730 on one frequency, but it accidentally leaks garbage 00:06:59.730 --> 00:07:02.529 onto another. Exactly. Let's say you have a cheap 00:07:02.529 --> 00:07:04.810 computer monitor. It's supposed to keep all its 00:07:04.810 --> 00:07:07.269 electronic noise contained. But if the shielding 00:07:07.269 --> 00:07:09.850 is bad, it might emit a spur that completely 00:07:09.850 --> 00:07:12.889 jams your home's Wi -Fi network. So the manufacturers 00:07:12.889 --> 00:07:15.629 do these sweeps to ensure consumer safety and 00:07:15.629 --> 00:07:18.009 compliance. They want to make sure devices don't 00:07:18.009 --> 00:07:20.129 cause radio frequency interference with other 00:07:20.129 --> 00:07:22.029 systems. Right. It's about being a good neighbor 00:07:22.029 --> 00:07:24.800 on the spectrum. OK. Let's pivot to the really 00:07:24.800 --> 00:07:27.379 high -stakes stuff, because the source brought 00:07:27.379 --> 00:07:29.199 up a completely different application that feels 00:07:29.199 --> 00:07:32.120 straight out of a spy movie. Technical surveillance 00:07:32.120 --> 00:07:37.040 countermeasures. TSCM. Sweeping for bugs. Yes. 00:07:37.560 --> 00:07:40.399 Corporate espionage. Government security finding 00:07:40.399 --> 00:07:43.899 covert listening devices. This is where portable 00:07:43.899 --> 00:07:46.800 sweep equipment becomes critical. But a bug is 00:07:46.800 --> 00:07:49.540 just a tiny transmitter, right? Why is it so 00:07:49.540 --> 00:07:51.759 hard to find? Couldn't you just look at the spectrum 00:07:51.759 --> 00:07:54.279 analyzer and see a big spike where it shouldn't 00:07:54.279 --> 00:07:57.100 be? If the person who planted the bug is an amateur, 00:07:57.399 --> 00:08:00.839 sure. But modern covert devices are incredibly 00:08:00.839 --> 00:08:03.699 sophisticated. They don't just transmit a continuous, 00:08:03.699 --> 00:08:06.600 obvious signal. They hide. They hide brilliantly. 00:08:07.120 --> 00:08:09.660 Some of them use burst transmissions. They'll 00:08:09.660 --> 00:08:12.459 record audio in a boardroom for five hours, compress 00:08:12.459 --> 00:08:15.040 it into a tiny data packet, and then fire it 00:08:15.040 --> 00:08:17.579 off in a microsecond burst. Oh, wow. So if your 00:08:17.579 --> 00:08:20.100 analyzer is sweeping at five megahertz per second 00:08:20.100 --> 00:08:22.100 and it's looking at the low end of the band while 00:08:22.100 --> 00:08:24.300 the bug bursts at the high end... You miss it 00:08:24.300 --> 00:08:26.410 entirely. It's gone. So how do you catch that? 00:08:26.610 --> 00:08:28.970 You have to leave the sweep running for an extended 00:08:28.970 --> 00:08:32.049 period using specialized software that builds 00:08:32.049 --> 00:08:34.409 a history of the spectrum. You're looking for 00:08:34.409 --> 00:08:37.529 that one weird momentary blip in the grass of 00:08:37.529 --> 00:08:40.289 the noise floor. That sounds insanely stressful. 00:08:40.629 --> 00:08:42.250 But speaking of stressful environments, let's 00:08:42.250 --> 00:08:46.269 talk about live events. Specifically, the example 00:08:46.269 --> 00:08:49.909 the source used, the American Super Bowl. Professional 00:08:49.909 --> 00:08:53.360 audio at live events. is arguably one of the 00:08:53.360 --> 00:08:56.059 most complex RF environments on the planet. I 00:08:56.059 --> 00:08:57.720 always just watch the game and think about the 00:08:57.720 --> 00:09:00.179 football. But behind the scenes, it's a massive 00:09:00.179 --> 00:09:03.399 radio logistics operation. Think about how many 00:09:03.399 --> 00:09:05.799 wireless devices are operating simultaneously 00:09:05.799 --> 00:09:08.559 at the Super Bowl. You have the referee microphones, 00:09:08.740 --> 00:09:10.840 the coach to quarterback headsets, the sideline 00:09:10.840 --> 00:09:13.240 reporters, the halftime show musicians with their 00:09:13.240 --> 00:09:15.539 wireless instruments and in -ear monitors, security 00:09:15.539 --> 00:09:18.139 personnel on walkie talkies, the blimp down links. 00:09:18.509 --> 00:09:20.870 and thousands of fans with cell phones. It's 00:09:20.870 --> 00:09:22.789 an absolute traffic jam. So how do they keep 00:09:22.789 --> 00:09:24.470 it all working? Because if the quarterback's 00:09:24.470 --> 00:09:27.129 headset cuts out during a crucial play, that 00:09:27.129 --> 00:09:29.350 is a disaster. That's where the frequency sweep 00:09:29.350 --> 00:09:33.029 saves the day. They have audio engineers, frequency 00:09:33.029 --> 00:09:35.690 coordinators, who optimize the use of the local 00:09:35.690 --> 00:09:37.909 radio spectrum. How do they do that? Do they 00:09:37.909 --> 00:09:40.450 sweep the whole spectrum? No. They usually perform 00:09:40.450 --> 00:09:43.049 a sweep limited to the operating bandwidth of 00:09:43.049 --> 00:09:45.889 the wireless devices being used. Before the game 00:09:45.889 --> 00:09:48.169 even starts, they map out the empty stadium. 00:09:48.240 --> 00:09:50.620 They find out what frequencies are clean and 00:09:50.620 --> 00:09:53.279 assign them. Like assigning parking spots. Fox 00:09:53.279 --> 00:09:55.500 Sports, you get this frequency. Security, you 00:09:55.500 --> 00:09:58.379 get this one. Exactly. They ensure all the local 00:09:58.379 --> 00:10:00.419 wireless microphones are operating at previously 00:10:00.419 --> 00:10:03.220 agreed upon and coordinated frequencies. But 00:10:03.220 --> 00:10:05.659 the real magic happens during the broadcast. 00:10:05.860 --> 00:10:08.659 Real time sweeping. Yes. They monitor the spectrum 00:10:08.659 --> 00:10:11.759 in real time because things change. A local news 00:10:11.759 --> 00:10:13.720 crew might show up in the parking lot and turn 00:10:13.720 --> 00:10:16.580 on an uncoordinated wireless mic that steps right 00:10:16.580 --> 00:10:18.899 on the referee's frequency. Causing an audio 00:10:18.899 --> 00:10:21.850 dropout. Or worse. interference. And there's 00:10:21.850 --> 00:10:24.629 also a phenomenon called intermodulation. What 00:10:24.629 --> 00:10:27.669 is that? It's when two separate signals mix together 00:10:27.669 --> 00:10:31.350 in the air and create a third, phantom signal. 00:10:31.929 --> 00:10:34.710 So even if everyone is on their correct assigned 00:10:34.710 --> 00:10:37.129 frequency, the physical interaction of those 00:10:37.129 --> 00:10:39.750 waves can create new interference. So the coordinator 00:10:39.750 --> 00:10:42.230 is constantly sweeping, watching the display, 00:10:42.570 --> 00:10:45.490 looking for these phantom signals or rogue news 00:10:45.490 --> 00:10:48.429 crews, and adjusting on the fly to prevent dropouts. 00:10:48.879 --> 00:10:51.059 It's high pressure whack -a -mole. If they do 00:10:51.059 --> 00:10:53.200 their job right, you never notice them. You just 00:10:53.200 --> 00:10:55.519 hear a perfect broadcast. That's incredible. 00:10:56.120 --> 00:10:58.039 Now up to this point, we've talked about continuous 00:10:58.039 --> 00:11:00.500 sweeps, sliding from point A to point B smoothly. 00:11:01.100 --> 00:11:03.620 But the source outlined a variation of this that 00:11:03.620 --> 00:11:06.120 is totally different. Frequency hopping. Right. 00:11:06.399 --> 00:11:09.379 What is the contrast there? Well, unlike a continuous 00:11:09.379 --> 00:11:11.919 sweep that glides across the band, frequency 00:11:11.919 --> 00:11:13.899 hopping involves switching from one frequency 00:11:13.899 --> 00:11:16.360 of operation to another. very rapidly. Keep jumping 00:11:16.360 --> 00:11:19.159 around. Exactly. And it does this in a random, 00:11:19.440 --> 00:11:22.379 rather a pseudo random pattern. The transmitter 00:11:22.379 --> 00:11:24.600 and the receiver both know the secret pattern, 00:11:24.860 --> 00:11:27.240 so they hop together in perfect sync. So instead 00:11:27.240 --> 00:11:29.000 of staying on channel five, it goes channel five, 00:11:29.080 --> 00:11:30.799 then channel 80, then channel 12, then channel 00:11:30.799 --> 00:11:32.919 50. Hundreds of thousands of times a second. 00:11:33.320 --> 00:11:36.299 Why do that? Why not just stay still? For security 00:11:36.299 --> 00:11:38.940 and reliability. This technique is used heavily 00:11:38.940 --> 00:11:42.259 in military comms, but also in consumer systems 00:11:42.259 --> 00:11:46.269 like CDMA code division, multiple access, which 00:11:46.269 --> 00:11:48.710 is a type of cellular technology. So if someone 00:11:48.710 --> 00:11:52.190 is trying to listen in or jam your signal, they 00:11:52.190 --> 00:11:54.570 can't because by the time their sweep detects 00:11:54.570 --> 00:11:57.330 you on channel five, you are already gone. You're 00:11:57.330 --> 00:12:00.490 on channel eight to a standard spectrum analyzer. 00:12:00.710 --> 00:12:03.129 Frequency hopping just looks like a slight elevation 00:12:03.129 --> 00:12:05.289 in the background noise. It hides in plain sight 00:12:05.289 --> 00:12:07.870 by never staying still. That is brilliant. It's 00:12:07.870 --> 00:12:09.950 a very robust way to share the spectrum. All 00:12:09.950 --> 00:12:12.029 right. Let's zoom out and recap what we've covered 00:12:12.029 --> 00:12:14.820 today. We started with the basic mechanics using 00:12:14.820 --> 00:12:17.360 a spectrum analyzer to scan the radio bands, 00:12:17.899 --> 00:12:20.379 balancing sweep rate against resolution, and 00:12:20.379 --> 00:12:22.720 viewing it all on a logarithmic display so we 00:12:22.720 --> 00:12:24.960 can see the whispers next to the shouts. The 00:12:24.960 --> 00:12:27.100 essential tool for visualizing the invisible. 00:12:27.419 --> 00:12:29.580 From there we looked at the practical applications. 00:12:30.179 --> 00:12:33.500 The FCC using sweeps to police the airwaves, 00:12:34.039 --> 00:12:37.159 engineers testing consumer tech to prevent spurious 00:12:37.159 --> 00:12:39.519 emissions, and the high -stakes environments. 00:12:39.879 --> 00:12:43.639 using sweeps to hunt for covert bugs in TSCM 00:12:43.639 --> 00:12:46.279 operations and coordinating hundreds of wireless 00:12:46.279 --> 00:12:48.919 mics in real time at the Super Bowl to prevent 00:12:48.919 --> 00:12:52.179 dropouts. Not to mention the evolution of frequency 00:12:52.179 --> 00:12:55.429 hopping to evade detection altogether. It really 00:12:55.429 --> 00:12:57.870 paints a picture of the bigger reality here. 00:12:58.330 --> 00:13:00.230 The radio spectrum, even though we can't see 00:13:00.230 --> 00:13:03.350 it, is a finite resource. It's a physical thing 00:13:03.350 --> 00:13:06.549 that requires constant vigilant management. It 00:13:06.549 --> 00:13:09.269 requires constant cleaning via these sweeps. 00:13:09.570 --> 00:13:11.590 Otherwise, none of our modern technology would 00:13:11.590 --> 00:13:13.870 function correctly. The interference would just 00:13:13.870 --> 00:13:15.850 overwhelm the systems. It's fascinating. And 00:13:15.850 --> 00:13:17.350 it leads me to a final thought I want to leave 00:13:17.350 --> 00:13:19.070 you with. As you sit there listening to this, 00:13:19.090 --> 00:13:20.830 I want you to look around your own living room. 00:13:21.110 --> 00:13:23.029 Think about the density of the signals around 00:13:23.029 --> 00:13:25.779 you right now. Exactly. We talked about audio 00:13:25.779 --> 00:13:27.860 engineers fighting for space at the Super Bowl. 00:13:28.159 --> 00:13:30.460 But what does the invisible noise look like in 00:13:30.460 --> 00:13:33.360 your house? You've got your Wi -Fi router, your 00:13:33.360 --> 00:13:36.159 smart TV, your Bluetooth headphones, your smart 00:13:36.159 --> 00:13:38.679 watch, maybe a baby monitor, the microwave in 00:13:38.679 --> 00:13:40.539 the kitchen. Your neighbor's router blasting 00:13:40.539 --> 00:13:42.440 through the wall. Hi. You are sitting in the 00:13:42.440 --> 00:13:46.039 middle of a dense chaotic crossfire of radio 00:13:46.039 --> 00:13:49.100 waves. It's an absolute miracle that when you 00:13:49.100 --> 00:13:51.700 hit play on a video, the signal finds a clear 00:13:51.700 --> 00:13:54.519 path through all that invisible noise and actually 00:13:54.519 --> 00:13:56.740 works. It's a testament to the engineering behind 00:13:56.740 --> 00:13:59.200 all this. It really is. Something to mull over 00:13:59.200 --> 00:14:01.519 the next time your internet buffers for a second. 00:14:02.399 --> 00:14:04.460 Have a little sympathy for your devices. They 00:14:04.460 --> 00:14:06.799 are fighting a war out there in the ether. A 00:14:06.799 --> 00:14:09.139 very noisy war. Well that's going to do it for 00:14:09.139 --> 00:14:11.019 us today. Thanks for joining us on this deep 00:14:11.019 --> 00:14:13.879 dive into the invisible world of RF sweeps. Keep 00:14:13.879 --> 00:14:15.820 wondering about the world around you and we'll 00:14:15.820 --> 00:14:17.500 catch you next time. Goodbye everyone.