[Antennaware] Electrons, Take 2

[Guy Olinger, K2AV]

One at a time...

> For example, we use often and without thinking the word "field". But we 
> fail to explain what this word means. Take for example the 
> "electromagnetic field" Evidently, this has to do something with electrons 
> as the abbreviation "Electro" is part of it when I asked Physics PhD about 
> his take of the work "field" he shrugged and informed me that this is an 
> abstract notion representing a bunch of line forces. When I insisted 
> asking what are the line forces composed of, he abruptly changed the 
> subject.

It is abstract. It is a mathematical concept which appears to map to 
observations. The point at which you object is the base layer of the 
concept.  What lies beyond is theory and usually controversial.

> So, if the antenna generated an Eletrofield, is it composed of electrons? 
> If so, where are they coming from? If they are originating somewhere in 
> the transmission equipment, by ejecting them through the antenna is the 
> transmitting equipment loosing mass?

The field as a concept is measured by comparing the local event to the 
distant induced event. For EM fields, of ordinary radio events, the 
"transmit" electrons only circulate locally.  This induces a lessor 
circulation of "receive" electrons. There is no observed literal exchange of 
electrons between the transmit and receiver conductors. If there is exchange 
one is usually talking about lightning and related phenomena.

> Take for example a transmitting tube. Its katode has a specific live span 
> after which it can not emit any electrons. Where have all its electrons 
> gone? Did the tube loose mass?

A transmitting tube is quite different. Here electrons are literally boiled 
off and propelled from the cathode to the anode, replenished from what ever 
is connected to the cathode. As opposed to an antenna where the copper gets 
to keep its electrons, the cathode undergoes changes from the constant 
depletion and replacement of electrons under heat stress. There is a good 
deal of material on this metalurgical process that can be found on the 
internet.

> A simple example will be a dynamo and bulb connected to it.. By turnig the 
> dynamo we are generating electricity (read electrons) that enter the bulb. 
> Some of them are spent in creating photons (light) some of them create 
> heat and some of them are simply lost in the never never land. And here 
> comes the same question. Where are these electrons/mass come from? From 
> the cooper in the coil? Why do we not detect mass loss of the coil after 
> some period of time?
>

The energy to create light and heat do not come from a "loss of electrons" 
but from the energy applied to rotating the dynamo magnets respective to 
conductors, inducing current (not loss) of electrons in the conductors, by 
varying the magnetic field around the dynamo output windings.

Go easy on the professor.  It's a hard thing to come up with convincing 
answers for anyone who walks up.  Reality does not depend on whether it can 
be explained or not.  But if reality can be predicted by equations, the 
equations become very useful tools.  The equations regarding fields do 
predict the energy output of the power generators at Hoover dam to a 
surprising number of decimal places, and adequately predict a good deal 
more.

Nobody can explain what a field IS, only explain the math that the word 
represents. But you already knew that.

73, Guy.