Thanks martin.  I should know better but have always thought of the 
power grid as a bunch of wires full of electricity.  Never thought of 
the SWR aspect and the changing demands detuning the network.
Thanks for the perspective.
Pat byrne, K9JAUAt 11:38 AM 8/19/2012, you wrote:
>         I was rather reluctant to post that message because I
>realize that we are all individuals. I thought I was terrible in
>math, also until I began to understand all the graphical
>information that originally seemed like so much noise. I am
>certainly glad I know Braille and I am glad I kept with the math
>and didn't give up because I eventually began making fairly decent
>grades in math, not excellent, but well enough to finish 6 hours
>of technical calculous which I needed for the two-year degree in
>electronics and computer technology. I thought I was going to
>teach basic electronics in our vocational/technical system back
>in the seventies and then I discovered these newfangled things
>called microcomputers to distinguish them from main frames that,
>at the time was what people meant when they said the word
>"computer."
>
>         When you are a student who is blind, there are lots of
>well-meaning but ignorant people who, if you listen to them,
>will steer you right in to the worst job in the world if you
>aren't careful.
>
>         Looking back over 40 years, the only thing I regret is
>not knowing enough at the time to be more firm about what I
>wanted out of life.
>
>         Amateur radio is a great way to stitch the rest of the
>world together so that instead of learning a bunch of facts that
>you will forget sooner than later, you learn how things relate
>to one another.
>
>         Physicists call this the grand unified theory and they
>haven't found it quite yet, but here is an example of the sort
>of thing I am talking about.
>
>         We learn in ham radio about antennas and feed lines and
>a lot of what we learn seems like black magic and we take it on
>faith. The name of the game is resonance or at least making it
>so that our transmitter transfers the maximum amount of energy
>from the final to the antenna so that we can warm the hearts of
>the pigeons above while we fruitlessly call CQ on ten.
>
>         The idea is to get rid of the capacitive and inductive
>reactance such that our antenna looks like pure resistance at
>the frequency we want to use.
>         Well, we have to tune the transmitter to the load at any
>frequency, even 60 hertz or 50 in most of the world.
>
>         Yes, the generators on the power grid work like a huge
>transmitter pumping countless megawatts in to the load which
>consists of all those power transformers and every electronic
>gadget from cell phone chargers to elevator motors and street
>lamps.
>
>         All across the world, electric companies monitor the
>power coming out of the generators and compare it with the load.
>In Winter, the load is different than it is in Summer because in
>Summer, we have more motors on line as air conditioners try to
>cool us all down.
>
>         Motors are highly inductive and their presence throws a
>phase shift in to the power grid which acts like more resistance
>and makes the generators have to work harder to deliver the same
>power. It is just like high SWR on your antenna and needs a
>tuner to fix things.
>
>         So, every Spring, just like the daffodils and birds,
>the capacitors come out of Winter storage. Power company workers
>switch them on to the line to tune the load back to a 1:1 SWR
>because we just waste energy if we don't do something about the
>problem.
>
>         In the Fall, along with the leaves falling off the
>trees, the technicians start disconnecting the capacitors as
>people turn off their air conditioners.
>
>         Don't even get me started talking about negative
>feedback loops. We learn about them in amateur radio when
>building amplifiers and you will soon discover that they rule
>the universe.
>
>         Well, enough of this. Those of you new to the hobby, I
>hope you stay curious. I just can't imagine amateur radio
>without the heavy learning factor. I probably would have let my
>license lapse decades ago if I thought it was just contests and
>rag-chews on two meters.
>
>         In case some of you wonder, I did my college years sort
>of wrong-side-out. I wanted to do electrical engineering but let
>well-meaning but ignorant advisors talk me in to journalism and
>broadcasting instead. I worked for two years and then went back
>and got a Master's degree in adult education. I went to work
>again and while working, finished the two-year electronics
>program in about 8 years, a little bit at a time.
>
>         It works a lot better if you know what you want and
>don't take no for an answer.
>
>Martin WB5AGZ