Wireless Technology – the world of AM, FM and Wi-Fi
Wireless Technology – Back to our Roots
Although many of us see Wi-Fi as the be all and end-all of wire free communication we could not be further from the truth. This article does encompass trends over the last hundred years which has seen a trend to move to UHF bands and use very sophisticated forms of modulation, the rule is always ‘the simpler the better’. Yes, I was in the telecom business many years back and yes, this article may lean towards older techniques and yes, we aren’t living in the dark ages but sometimes we lose sight of the skills that our forefathers (and mothers) had. Modern trends are extremely reliable but when they do fail we are miserable, from your local power grid to an internet connection.
Over the last two hundred years there has been, in my book, four great strides to bring us modern radio telecommunications:
- Firstly, the discovery of electromagnetic waves – Maxwell, Hertz and Hughes.
- Secondly, the discovery of the vacuum tube principle, thereafter it’s implementation in amplitude modulated circuits.
- Thirdly, the design and implementation of FM or Frequency Modulation.
- Fourthly, the strides taken to reduce bandwidth with increased power to deliver a rock solid signal, the implementation of SSB. (Single Side Band).
One thing that stands out, head and shoulders above the achievements of commercial enterprises such as Bell Labs whom have been credited with almost anything related to telecommunications is the perseverance and incredible work done by the ARRL (American Radio Relay League).
Although most youngsters would never have heard of SSB, like the challenges facing RCA to develop a broadcast picture in colour on the same frequency and bandwidth of a monochrome signal, SSB was indeed an incredible leap forward – nearly 100 years ago.