On Mon, 5 Nov 2007 17:30:26 -0800, "Sal M. Onella"
wrote:

So, when you were on staff at USN ET "A" School, where we both taught, did
you know better than the "reflected power" legend/old-wives-tale/heresy?
Hell, that's where I first picked it up !!!!!!!!!!!!!!!

Hi John,

My path up through "A" school was through the Radar branch (I was the
only ETR2 in the Communications Branch when I taught there). The
Radar training gave us hands on experience with equipment that
presented both lumped (pulse forming network) AND line (Magic T and
such) designs. Also, reflected POWER was palpably lethal in both
applications. Melodramatic criticism of the fine points in
terminology carried little weight in lab exercises.

Luckily, I had the presence of mind as a student to hie myself into
Frisco to buy Terman's "Electronic and Radio Engineering." The Navy
course of instruction and training manuals so perfectly dove-tailed to
that book that the fit was a precision match. The "A" school syllabus
didn't go nearly to the depth of detail as offered by Terman (the
ET1&2 and ETC course work did), but it did heavily touch every chapter
found in that tome.

Insofar as heresy, the syllabus was rife with it. We taught that
antennas that were too short could be made to appear longer by the
addition of the "missing" wire in the form of a coil. Similarly, a
too long antenna could be reduced in length by inserting a capacitor.
The teaching aid was to think of the coil symbol as a spring that
could be stretched to lengthen the short antenna, and cap symbol as
providing space enough between the plates to collapse the extra length
of a too long antenna. Clearly the metaphors wheeze, but are
effective well beyond mathematical proofs that could only serve as
sleeping pills.

Before the purists roll their eye's and mutter "tut-tut" under their
beards - instruction was complete to point out these were short-cuts
as memory aides and did not serve as a complete discussion on the
topic. Reflected power certainly fell into that category as its
hazard was positively destructive and not a mental exercise subjected
to debate in a perfumed symposium.

Anyone with radar experience can fashion the plumbing to steer
reflected power to any load. -um- reflected energy be damned at that
point as any reflection was inherently returning to a source that was
long dormant (in terms of microseconds) and ready to dissipate
anything that came down the pipe. The whole point of the magnetron's
success in war was its robustness in the face of catastrophic
mismatches. The PFN might flame out or the thyratron burst, but the
magnetron would survive.

73's
Richard Clark, KB7QHC