[Discuss-gnuradio] RE: Discuss-gnuradio Digest, Vol 4, Issue 19

[MacLeod, Matthew]

First of all..apologies for spamming the list with the list right now. I
hate having to use outlook at work...it makes it too easy to do silly
things.

/*
This is kind of a loaded analogy, but even so, it is not true.  If your bulb
is flashing, it produces sidebands.  If you filter out the carriers (both
yours and the megawatt one), you can still receive the sidebands.

It is also misleading.  The are petawatt (maybe stronger) light sources all
around us (i.e. the sun, stars, etc.)  That doesn't mean that I can't see an
LED.  It just means I have to be closer to the LED to see it. 

Very false.  Filtering separates color/frequencies.  
*/

Basically you're applying radio logic here to the colour analogy. This was
my whole point to begin with - the colour analogy is bad, and doesn't really
explain anything, and in fact just confuses the issue. 

/*
Exactly the point he's trying to make.  If you can't read the signal then
you need better glasses.
*/

I totally agree. Which is why I think the article would be much more
coherent if it focused on how eyes are different than antennas, rather than
the colour idea. Eyes are directional, which is really good as long as
you've got a brain hooked up to them that can look around and focus on
things. This is much harder (but yes, will be possible) with new antenna
technology.

The other problem is that RF sees objects different than we do. The building
your sitting in would be full of translucent objects and walls with all
sorts of refractive indices that would make it much more confusing to say,
read a letter taped to the wall 3 feet away. This is both good and bad, as
you could see many more things outside, but in a house of mirrors sort of
way. We're just now coming to grips with how multipath can be used
constructively, however.

The other thing that irks me is this misconception that suddenly there'll be
infinite bandwidth and universal connectivity. You just switch to a
different colour! Eventually, you still run out of colours, no matter how
much everyone is frequency hopping or spreading. This is especially true
because it's hard to make a good antenna for a wide cross-section of
frequencies, so devices will still be limited in the bands they can access
no matter how good the processing is. To stick to the analogy, we can't see
infrared and ultraviolet, even though our brains could handle it.

Don't get me wrong, I'm all for spectrum deregulation and intelligent
radios, I'm just wary of misleading statements being attached to the
movement. Any time grand promises are made the skeptics BS filters tend to
activate, and I don't want the message to be thrown out because of
over-statements.

Matt MacLeod