Can you hear me now?

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Happy International Women’s Day!  

As we celebrate women in technology this month, it is wonderful to highlight one of the leading pioneer’s of Bluetooth and WiFi techniques.  Hedy Lamarr, a famous actress in the 1940’s, played a pivotal roll in “spread spectrum” science during World War II.

It was her knowledge of jamming technology, that was crucial in ensuring that torpedoes could be set off course during the war.  Years later, in 1957, the technology was created into a “sonobuoy” –  a device that is dropped into the ocean for anti-submarine warfare or, as is now the case, vast underwater research based on sonar frequencies.  In 1962, the same technology was installed by the Navy during the Cuban missile crisis.

The spread spectrum science is used today in Bluetooth technology although still sometimes used in WiFi signalling.

So what is the difference between the two?

“Bluetooth, developed in the late 1990s, is a technology designed to enable short-range wireless communications between electronic devices, such as between a laptop and a smartphone or between a computer and a television. Bluetooth works by using radio frequencies, rather than the infrared spectrum used by traditional remote controls.  As a result, Bluetooth eliminates the need not only for a wire connection but also for maintaining a clear line of sight to communicate between devices.”1.

“Wi-Fi is similar to Bluetooth in that it also uses radio waves for high-speed data transfer over short distances without the need for a wire connection. Wi-Fi works by breaking a signal into pieces and transmitting those fragments over multiple radio frequencies. This technique enables the signal to be transmitted at a lower power per frequency and also allows multiple devices to use the same Wi-Fi transmitter.”2.

As we can see, there is a difference between the two and, while you can sometimes use bluetooth without a wifi signal, the two are required the majority of the time to function in the environments that we have today.  Wifi transmits at a much higher frequency than say your cellular devices.  Common rule is the higher the frequency, the more data that can be passed over the spectrum.  Because this frequency is sensitive you’ve likely experience spots in your home where your devices doesn’t work as well or you can’t hear the caller.  We all have that “dead zone” usually around the load barring wall that has internal steel construction or the furnace room that sends all kind of interference into the spectrum – not to mention the interference if you microwave is on or your trying to chat on the phone while doing your laundry!   This is one of the reasons that cell phones are not allowed in the wards at hospitals – two frequencies clashing between your device and a medical one is not an optimal outcome.  While these signals are getting more resilient with further technology, it’s still important to understand why a “no cellular devices here” sign exist.

The Internet of Things (IoT) runs a low wifi frequency for your Zumba, door locks. lights etc.  and is set up over your network – the PAN example from our Tea and Tech Podcast ~ Episode 3.  As “multi radio mesh deployments” become more standard the world of WiFi will surely be less of “can you hear me now” and more of “can you link to me now”

  1. https://www.britannica.com/technology/wireless-communications
  2. https://www.britannica.com/science/radio-wave

 

 

 

 

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