OK RRAA Group Let's get Real:

DC to daylight! Which end of the spectrum is most interesting?

There often seems to be disagreement, dare I say "rancourous", among the
denizens of RRAA on certain details of the dynamics of em waves and certain
wave phenomena, dare I say "reflections".

Most hams are practical folk, interested in phenomena that occur (only)
within our legally assigned frequency bands. A select few are interested in
what happens outside our legally assigned frequency bands, and at least one
of our RRAA bretheren often takes us on excursions all the way up to
"daylight" to make his points futher down the spectrum! i.e. He takes us
up into the nether regions of optical frequencies to make his points. (God
Bless "Hecht"!)

Throughout all of the ensuing discussion that we "lurkers" overview, I have
always been curious about what happens if we were to take or frequency
excursions to the other extreme.

I believe that we are legally allowed to radiate in the DC band!

Most of us RRAA'ers seem to accept the physical reality inherent in the
assertions of James Clerk Maxwell's (Actually Oliver Heavisides!) elegant
and widely celebrated simple set of four partial differential equations and
their auxilliary relations. Where is dear old Reg when we need him?

Most of us RRAS'ers alos seem to "know" that, at least at Radio Frequencies
(RF), there exist both guided and free space electromagnetic "waves", and
that during the "life" of such waves, the situation of the simultaneous
existence of both "incident" and "reflected" waves often occurs. We all
agree, because of "optical" excursions we have been taken on by our "ptical
frontiersman", that situation occurs whether or not those waves are "guided"
(by transmission lines, a.k.a waveguides) or "free".

Aside: We all seem to know that it is strictly the "acceleration" of
electric charges that causes the radiation of radio waves, or if you prefer,
the emission of photons. I believe that the extant wave versus particle
"paradox" is irrelant to my following comments, assertions and questions.
Also I believe that the dividing line between transient and steady state
phenomena may be considered to be insignificant and so considered to be
irrelevant as well.

Frequency, or spectrum, through the Supreme Force of the Universe's gift to
us of "The Sinudoids" is intimately related to circular motion.
Acceleration we know is the rate of change of velocity. In the steady state
at DC electric charges are moving at a constant velocity. Thus when moving
in a straight line at constant velocity there should be no "waves" launched
or radiated, no?

However, as mechanics or Engineers, we all understand the reality of
centrifugal force and centripial acceleration. Some of us may actually
recall Coriolis acceleration. [grin] I was in New Zealand last year and
indeed the water does go down the sink with the opposite circulation. The
water would not do that without the existence of the Coriolis Force. But I
digress!

The reality of electric charges is clearly accepted by all denizens of RRAA,
although some might argue about "holes" [grin].

Clearly then... even constant velocity steady state charges (DC) that
circulate at a constant linear and angular velocity around the guided
helical path of a solenoidally shaped conductor, otherwise known as a coil
or inductor, say for instance the ubiquitous loading coil of a Bug Catcher
whip, are subject to CENTRIPIAL ACCELERATION and must perforce emit photons,
no? Does a coil carrying DC radiate? If so how efficiently?

My point here is the assertion of the real existence of DC waves either
guided or free!

Q0: Is there electromagnetic radiation (are photons emitted) from a
solenoidal (helix) carrying DC because of the centripital acceleration of
the charges?

Q1: Do electromagnetic "waves" exist at DC, whether guided or free?

Q2: Can incident DC "waves", whether guided or free ever be "reflected"?

Q3: Can a VSWR be measured (at zero frequency) on a transmission
line/waveguide that supports DC?

Q4: Is the VSWR at DC related, in any way at all to the VSWR at higher
frequencies?

Pete, just plain crazy, none of this is reality!

Let's get practical then... most RRAA'ers seem to agree that a Bird Model 43
clearly measures indident and reflected waves. The generic name for a Bird
is "reflectometer". Bird's, being "real practical devices" do have
practical frequency range limitations and their accuracy and precision of
the measurement of actual reality falls off below and above their (rated)
the frequencies that define their rated bandwidth of operation. i.e. Bird's
are not "accurate" from DC to daylight! But if one had a "Perfect Bird" and
we could measure transmission line guided waves all the way down to DC.

Q4: If the Bird can't do it, is it even possible to construct a
reflectometer instrument that can measure reflected waves all the way down
to DC (zero frequency)? I have one here at home that I made myself. Where
can I buy one?

Q5: If waves do not exist at DC, then at what magic frequency, lets call
this frequency f(mgc), do waves cease to exist?

Q6: Below what magic frequency, lets call it f(mgc), do radiation and or
reflection phenomena stop?

Q7: What is the difference between a "conjugate match" and a "Zo-match" at
DC?

Food for thought, eh?

I miss dear old Reg!

Thoughts comments...

--
Pete k1po
Indialantic By-the-Sea, FL