Cecil Moore wrote in news:mO0nj.4140$J41.257
@newssvr14.news.prodigy.net:

Keith Dysart wrote:
Not at all. The equations don't just stop working at 0 frequency.

As a matter of fact, EM waves cannot exist without
photons. There is zero wave activity at DC. Therefore,
the forward power and reflected power is zero at DC
steady-state.

You really should try to stop thinking about photons
for just a short while.

Yep, you guys would like to sweep the technical knowledge
from the field of optical physics and quantum electro-
dynamics under the rug. One wonders why.

Think of it as a long pulse. That should satisfy your
need to have 'waves'.

No, only photons will satisfy the definition of EM
waves. There are no photons. There are no waves. There
are no forward and reflected powers. There are no
changing E-fields or H-fields. There is not even any
movement of electrons associated with the source
voltage.

Food for thought!

There is no such thing as DC! How’s that you say? You have to turn it on
sometime and someday you may turn it off. There for, DC is just very low
frequency AC.

As another example of physics over thinking, I once had a physics
professor describe in detail how an electric motor works using Quark
physics. Very interesting but it has no practical value in using electric
motors. Much like this long thread has nothing much to do with antennas.


John Passaneau W3JXP

"JOHN PASSANEAU" wrote in message
...

There is no such thing as DC! How's that you say? You have to turn it on
sometime and someday you may turn it off. There for, DC is just very low
frequency AC.


John Passaneau W3JXP

That's false reasoning OM! Alternating current is not the same as
discontinuous current. In the example you provide, a DC supply is either off
or on; it does not reverse polarity! You do not make AC by switching on and
off DC, even at 50 Hz (or your 60 Hz)

Suzy wrote:
"You do not make AC by switching on and off DC, even at 50 Hz (or your
60 Hz)"

Not without inductance to provide the missing half cycle. Remember
vibrator supplies and their solid-state equivalents?

Best regards, Richard Harrison, KB5WZI

Suzy wrote:
"JOHN PASSANEAU" wrote in message
...
There is no such thing as DC! How's that you say? You have to turn it on
sometime and someday you may turn it off. There for, DC is just very low
frequency AC.


John Passaneau W3JXP

That's false reasoning OM! Alternating current is not the same as
discontinuous current. In the example you provide, a DC supply is either off
or on; it does not reverse polarity! You do not make AC by switching on and
off DC, even at 50 Hz (or your 60 Hz)

But through the techniques of linear circuit analysis, we can split the
pulsed DC into two components, a pure steady DC component and a
symmetrical AC component. We can do two separate analyses with the two
(AC and DC) excitations, and sum the results. The answer will be exactly
the same as if we had done the calculations directly. One can then
reasonably claim that the switched DC is the sum of an AC waveform and a
pure DC component.

Roy Lewallen, W7EL