Subtitles section Play video Print subtitles W8MI! Whiskey right Mexico India… Dennis, do you read me? Can I just, like, text you next time? This is weird... Can you read me DNews, what's your 20? Sciencemen Trace here hamming it up for DNews. Remember that time Eleven needed to talk to Will in the upside-down? The kids were excited because they got to use a ham radio. Ham radio is an amateur radio broadcasting system -- people who operate ham radios are called "hams!" There are nearly three million ham licenses worldwide: with major populations of hams in Japan, Germany, England, Indonesia, South Korea. According to the National Association for Amateur Radio, there are more than 727,000 licensed ham radio operators (called hams) in the U.S. -- making us the second largest community.2 I say community, because that's what amature operators says it's all about. Ham radios are exactly like any other radio, but instead of your local rock, country, or Beyonce station playing nothing but the hits, nothing but the hits… Instead, it's Jenny from the block, Sloan from Canada, or Siso from Swaziland; right there, in your radio! Aside from the fun community aspect, in times of disaster, when cell towers and internet are down, hams can still communicate with each other and emergency services. All radio works the same, even ham radio. When electricity travels through an antenna of some kind, another antenna can pick it up and decode it. Tune a radio to a static AM station, grab a nine volt battery and a coin, hold them near the antenna and connect the studs with the coin. The radio will pick something up! The electricity is "broadcasting" radio5. The battery will only go a few inches, but with more power, the signal can go farther. Thanks to advances in technology, we can pinpoint exact frequencies to broadcast on, where the radio waves are precisely tuned so they don't interfere with each other. According to HowStuffWorks, ham bands are "above the AM radio band (1.6 MHz) to just above the citizens band (27 MHz) (also known as CB radio!)" And on those ham bands, the FCC says people can send 1,300 different types of communication using voice, video, digital, telegraphy (morse code!)... you name it -- it's all shared space, though. So if someone else is using that frequency, it becomes a party line. There are three main Ham radio bands: HF, VHF, and UHF. With UHF or "ultra high frequency" the waves leave the antenna and bounce off buildings and around solid things, but can't go2 around mountains. VHF "very high frequency" waves can pass around some obstacles, but can still be blocked. These are mainly "line of sight" antennas. Straight lines. Think FM radio. Which is why it doesn't work over the curve of the Earth or behind a mountain. But, that doesn't stop all radio. HF "high frequency" waves are my favorite in this scenario… Because, starting about 50 kilometers above you is the ionosphere -- an electrically charged layer of the atmosphere. Ham radios using the HF range can bounce their waves off the ionosphere, creating a Sky Wave. That wave "skips" to another point on the Earth… or hits another antenna -- which might rebroadcast it! All ham signals can be rebroadcast… someone can pick it up, and send it out again. Like a relay! I wasn't kidding when I said Swaziland! But Swaziland isn't the furthest radio can reach. In 1969, an operator in Louisville, Kentucky picked up radio between Armstrong and Aldrin on the moon during Apollo 11. He even recorded President Nixon's message to them! You can still talk to astronauts with amature radio today. The ionosphere doesn't bounce all signals! On the International Space Station, the crew has access to a ham radio. When they're overhead, their 2-meter FM transceiver allows the ground can have a chat with space. You can see for yourself that the astronauts are overhead, talk to them while they're there, and then they fly away. TAKE THAT If you're fascinated by how far afield ham radios can reach, the new CW show, Frequency takes that even further. In the show, a female police detective in 2016 discovers she can reach her estranged father over the airwaves of her ham radio. Plot twist: He's in 1996! Don’t miss the Series Premiere of Frequency, Wednesday October 5th, at 9/8c only on The CW. It's pretty amazing that we can do all this with waves of electromagnetic energy. The more you think about it, the cooler it gets. Which is why DNews Plus did a whole thing on LIGHT! What is it anyway?! Wait, what? You don't know DNews Plus? It's like DNews, but ten times longer. We take a big topic, like Artificial Intelligence, Leaving Earth, or Light -- and get nerdy with it. If you're smelling what we're cookin' subscribe to DNews Plus on YouTube, or listen to it as an audio podcast on Soundcloud or iTunes. Have you ever tried a ham radio?
B1 radio ham antenna dnews frequency hf How You Can Talk To An Astronaut From Home 140 9 李柏毅 posted on 2017/03/03 More Share Save Report Video vocabulary