The Tham Luang Nang Non cave rescue in Thailand was an interesting application and a very challenging communications problem. Kudos to the brave rescuers, and our condolences to the family of the brave Navy Seal who died in an earlier rescue effort; he was a true hero.

A big part of the communications effort challenge that this rescue team encountered involved a cave that was 2.5 miles long. A traditional walkie-talkie that rescuers use would never provide communication over this stretch of rock and water. The typical rescue radios use a point-to-point communication method or another method where each individual handset talks to a common base; these technologies would not work in this harsh environment.

This is where Maxtech entered the picture. Their designs take advantage of transceiver technology to create a software defined radio (SDR) and develop a protocol that created an ad hoc network. Instead of relying on an architecture that goes from point A to point B in one hop, they have a mesh, so that if you can’t reach the destination directly, you hop from radio to radio.


Maxtech Networks provided communication solutions for the Thailand cave rescue effort.

These transceivers can span from 10s of MHz to 6 GHz carrier frequency with arbitrarily low bandwidths down to 50 MHz. With that kind of flexibility, you can find a frequency that propagates well in a particularly challenging environment. If the propagation is poor, you can go to a narrower bandwidth that allows for a longer range link.

Uzi Hanuni, founder and CEO of Maxtech Networks said, “Our technology can be encapsulated in various forms. The Mini PCI Express card [we use] is our own technology, only it has a field-programmable gate array (FPGA). This is the key fundamental component. We are using the Analog Devices AD9364 high-performance, highly integrated radio frequency Agile transceiver for communications. In addition, we are also using the Samsung ARTIK 7, which is a module that offers great performance for high-end gateways with local processing and analytics to improve latency and responsiveness. With the ARTIK 7 is an Intel Cyclone III FPGA.”

ADI is developing more communications products like this, with some interesting new capabilities specifically for this market, since many of these radios that first responders use are quickly becoming obsolete.

There are three generations out there of ADI's Radioverse, and the company provides supported tools, reference designs, and app notes alongside this leading-edge technology for radio designers to create new uses for communications in challenging setups. The AD9364 RF Agile transceiver is one of the solutions that enables advanced communications technology. Maxtech is a good example of creative designers who develop unique radio solutions using the tools and ICs ADI offers.

Tony Montalvo has been at ADI since 2000 and started the ADI transceiver group. He has been an ADI Fellow since 2012, and the Director of Technology for ADI’s communications business for the last year. He is the force behind these communications IC efforts. Montalvo was one of the leading guys who developed the transceiver as we know it today when he was at Ericsson early in his career. His claim to fame is being the architect behind a receiver IF chip that eliminated a bulky 2nd-IF filter. You can see an interview with Montalvo here.

There are several other first responder uses of Radioverse out there including firefighters that have a module on their shoulder with a radio and video feed so that the commander can assess the situations encountered by his team.

I was a New Yorker during the 9/11 Twin Towers attack and I know some of the firefighters and police responders that had communication difficulties due to different radio technologies that various rescue teams had. So what ADI is doing is commendable and they are helping make a better, safer world through innovative technology. That’s what we, as engineers, strive to do. Hanuni had an interest in devising a better form of communication technology after the attacks in 2001, where he saw many first responders cut off after the World Trade Center towers collapsed and their radio antennas were damaged.

Montalvo said that unlike 9/11, which had an immediate need, the situation in Thailand unfolded a bit more slowly so that they were able to get an optimal solution in there. It does speak to the need of having the kind of solution that Maxtech provides at hand.

The cave rescue effort highlighted exciting technology that could inspire young minds to pursue STEM careers. I wondered if the rescuers needed to lay down radios along the length of the 2.5-mile cave. Maxtech described the technique to CNN. Let's look at how they did it.

[Continue reading on EDN US: Maxtech technology]

Steve Taranovich is a senior technical editor at EDN with 45 years of experience in the electronics industry.

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