A little about me, and a little about how technologically amazing ADSL2+ & WiFi are.

About Me

I’m what you’d call a Technician, in the traditional sense – that is to say before the days that being a ‘Nail Technician’ (as in fingernails) was a job.  By that I mean I can understand how something works, and install it, and maintain it for the end user according to the manufacturer’s instructions.  Certainly in some cases I can go beyond that – as I often home brew antennas and what not, but I didn’t have what it takes to be an Engineer professionally.  Read on if you want to find out more:

I studied Engineering at University for a year, but the truth was I am not particularly mathematically inclined.  Most of the good Engineering knowledge is based on Calculus and Fourier Transformations, and while all that stuff is done via computers and calculators in the real world, I was never good enough to do it by hand and pass the maths classes.  So when I was offered a good paying job as an IT Technician at the end of my first year, I figured it was probably a better option than spending 5 years+ slugging through a 4 year degree and potentially ending up in a job where I had to do maths.  Looking back on it, I know now I’d never have gotten in that situation; we don’t design and build things in Australia anymore so it’s not like I turned my back on oodles of money.  I would have ended up as a project manager (aka a technician who doesn’t actually do anything), and hated it.  Plus, I would never have excelled in that field anyway.

And here are some examples as to why I’d never make a world class engineer.

ADSL2+

Did you know the internet technology, ADSL2+, uses 512 separate frequency channels (Bins), each consisting of up to 16 tones using Quadrature Amplitude Modulation.  Just think about that for a minute.  Someone(s) out there has designed a chip that concurrently runs Fast Fourier Transformations to track and decode 512 individual frequency bins, each of which can contain up to 16 tones which encode data based on the phase difference between those 16 tones.  ADSL2+ is quite literally 512 traditional analogue modems, all running at once, each on its own 4kHz frequency channel, on the one phone line.

The equivalent in the Amateur radio world would be 512 simultaneous ‘16PSK-4096’ transmissions across 2MHz of bandwidth.  Can you imagine that? 

WiFi

WiFi is similar, some variants use QAM256 (eg data is encoded based on the phase relationship of 256 simultaneous tones), across up to 160MHz of bandwidth.

Think about that.  Can you imagine the mathematical techniques needed to process in real time the phase difference between 256 freaken tones?  Remember, you need to account for things like multipath fading, etc etc.  The new stuff even does ‘beamforming’ by introducing phase delay between multiple antennas to optimise the reception at the end user’s device, based on signal reports sent to the WiFi Access Point by the laptop or tablet.  All automatically!!!!

I doubt there is more than 20 people worldwide who fully understand these technologies.  But there doesn’t have to be.  One company patents the design, and everyone else just licences it.

There are two morals to this story really:

• I am nowhere near smart enough to contribute anything new to the world of engineering. I’m just not that good at maths.
• The ‘digital’ modes we use in our Amateur radios are ‘childs play’. As amateurs, what we have available to us is so far behind cutting edge technology (mainly in terms of throughput) its hardly fathomable.

There is no conspiracy of course, I’m sure some HAM out there IS smart enough to bring this kind of tech to amateur radio, you know, the kinds of brains that came up with JT65.  But remember, we’re in a hobby were people jump up and down because ‘eSSB’ uses 6KHz of bandwidth.  Can you imagine the furore if someone used 32KHz for a digital mode on HF?  Let alone the 160MHz of bandwidth the latest WiFi uses?

The story is not all bleak of course.  We do still innovate.  The moon bounce mode JT65 and the new JT9 HF mode come to mind.  The difference is we innovate in terms of signal resilience over long distances, using as little bandwidth as possible.

XU7AGA’s Maxim #3:  High Throughput, Low Bandwidth, Signal Resilience.  Choose any Two.

And that’s enough about me.

73,

Jarrad