A fundamentally new approach to building radio transmitters could open previously impossible communication channels for warfighters
Here’s something easy to forget when you are chatting on your cell phone or flipping channels on your smart TV: although wireless communication seems nothing short of magic, it is a brilliant, reality-anchored application of physics and engineering in which radio signals travel from a transmitter to a receiver in the form of electric and magnetic fields woven into fast-as-light electromagnetic waves. That very same physics imposes some strict limits, including ones that frustrate the Department of Defense. Key among these is that radio frequency signals hit veritable and literal walls when they encounter materials like water, soil, and stone, which can block or otherwise ruin those radio signals. This is why scuba buddies rely on sign language and there are radio-dead zones inside tunnels and caves.
With his newly announced A Mechanically Based Antenna (AMEBA) effort, program manager Troy Olsson of DARPA’s Microsystems Technology Office is betting on a little-exploited aspect of electromagnetic physics that could expand wireless communication and data transfer into undersea, underground, and other settings where such capabilities essentially have been absent. The basis for these potential new abilities are ultra-low-frequency (ULF) electromagnetic waves, ones between hundreds of hertz and 3 kilohertz (KHz), which can penetrate some distance into media like water, soil, rock, metal, and building materials. A nearby band of very-low-frequency (VLF) signals (3 KHz to 30 KHz) opens additional communications possibilities because for these wavelengths the atmospheric corridor between the Earth’s surface and the ionosphere—the highest and electric-charge-rich portion of the upper atmosphere—behaves like a radio waveguide in which the signals can propagate halfway around the planet.
“If we are successful, scuba divers would be able to use a ULF channel for low bit-rate communications, like text messages, to communicate with each other or with nearby submarines, ships, relay buoys, UAVs, and ground-based assets, Through-ground communication with people in deep bunkers, mines, or caves could also become possible,” Olsson said. And because of that atmospheric waveguide effect, VLF systems might ultimately enable direct soldier-to-soldier text and voice communication across continents and oceans.
To date, there’s been a huge and expensive rub to actually pulling off low-frequency radio communication in the versatile ways that Olsson has in mind. The wavelengths of VLF and ULF radio signals rival the distances across cities and states, respectively. And since longer wavelengths have required taller antennas, communications in these frequency bands have entailed the construction of enormous and costly transmitter structures. A VLF antenna that the Navy built on a remote peninsula in Cutler, Maine, in the heat of the Cold War just to send a trickle of data to submarines makes the point: the gargantuan transmitter complex occupies 2,000 acres, features 26 towers up to 1,000 feet high, and operates with megawatt levels of power….READ MORE
Equipment
Short overview of the BP-307, a new high capacity 7.2V / 3350mAh (typ.) Li-Ion battery pack designed for Icom’s latest range of IP, LTE radio and selected Amateur radio products including the new IC-705 QRP SDR transceiver. The BP-307 is IP... Read more
![Nice presentation of Power Genius XL by Dan, N7HQ [ VIDEO ]](https://qrznow.com/wp-content/uploads/2021/03/160845523_819231712134810_4516260191051892817_o-90x60.jpg)
Antenna
Chameleon is releasing a new receive only loop, the CHA-RXL. Lets get it on the roof, test it out and talk about why receive loops can be pretty awesome. The CHA RXL is a new design high performance Low Frequency (LF), Medium Freq... Read more
Recent Posts
Ducie Island 2018 DXpedition Plans Coming Together for this Fall
The Perseverance DX Group (PDXG) reports that its plans to activate the protected marine area of Ducie Island from October 20 to November 3, 2018 are... Read more
VA3XPR launches an all-digital Yaesu System Fusion repeater in Toronto
Great news for digitally connect hams in the great Toronto area! Today, VA3XPR launches an all-digital repeater using Yaesu’s System Fusion C4FM FDMA... Read more
How does the solar eclipse affect Ham Radios?
HUNTSVILLE, Ala. – Many ham radio operators are excited for the upcoming solar eclipse. “This is my first chance of being a part of a tot... Read more
A WIRELESS WEB-CONNECTED MORSE CODE KEYER
“[Kevin] recently scored a Morse code keyer/sounder unit from the 1920s on eBay. While many hams would love to use an old keyer fo... Read more
“June 2020 Festival of Frequency Measurement” Seeks Ham Radio Volunteers
Grad student Kristina Collins, KD8OXT, in Cleveland, Ohio, is looking for radio amateurs and shortwave listeners — particularly in Africa and Asia — t... Read more
Recent Posts
Super Battery Booster MFJ-4416C
Today`s compact 100-watt HF rigs are designed to operate from about 12-16 volts, with output signal distortion, output power problems, and transceiver... Read more
Tornado damage to legendary KOMA tower array
Damaged KOMA-AM towers (now KOKC) after the March 25, 2015 tornado. A close-up view of the standing tower’s damage. Engineers deemed the... Read more
The PackTenna Mini 9:1 Random Wire Antenna Antenna
http://www.packtenna.com Read more
VK0EK Radio Team Leader and QSL Manager Announced
VK0EK “We are pleased to announce the appointment of Dave Lloyd K3EL as the Radio Team Leader. Dave is a PhD chemist, with experience on... Read more
How to Find Online Ham Radio Exams
How to Find Online Ham Radio Exams Read more
