Progress in Electronics

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rdonnay
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Progress in Electronics

#1 Post by rdonnay »

I am always amazed at the progress of technology, especially in the area of radio wave reception.

When I was a teenager, I built radio receivers and was blown away by the concept of the superheterodyne receiver that used vacuum tubes to convert AM signals to something I could hear in a speaker. I thoroughly understand electromagnetic wave properties because I was a radar and communications technician in the U.S. Navy and it was my job to know this stuff. Back in the 1960's we needed to transmit radar pulses at 220 Megawatts so we could get sufficient signal in the bounce back to detect in a receiver. Receiving amplifiers were incredibly sophisticated back then, or so I thought. We had to be able to detect signals in the Microwatt level (millionths of a watt or about -20 DBM). The cost for such capability was very high. I worked on the electronics for remote control helicopter drones back then which required expensive transmitting and receiving equipment and still could not detect signals lower in strength than about -20 DBM.

Fast forward about 46 years and I am now flying a different kind of drone. It's electronics is now very inexpensive and capable of receiving signals from a GPS satellite that are in the femtowatt range (-127 DBM). This means that receivers today are 1 trillion times more sensitive than what we used in our radar systems 46 years ago. Now that is impressive progress. It also explains how we can send a space probe to Pluto and receive signals that contain perfect digitized photographs.

https://en.wikipedia.org/wiki/DBm
https://en.wikipedia.org/wiki/Orders_of ... de_(power)
The eXpress train is coming - and it has more cars.

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