On Sat, 21 Feb 2009 19:37:34 -0600, Frnak McKenney
wrote:

Matching provokes heated debates that in times past ran to 600+
postings - few knew what they were arguing (but enjoyed arguing
nonetheless) and little was offered.

What I think I'm looking for would be a point of reference that
would let me, if not exactly evaluate the facets of such an
argument, at least be a foundation for forming a testable opinion of
my own.

Opinion is, after all, what powers the Internet.

A JFET at these frequencies does satisfy the naive requirements of
"matching," but that giving you a reception solution doesn't always
follow.

In my current state of ignorance of the subject, this sentence has
the appearance of a Zen koan: something that sounds non-sensical at
first glance, but which, after sufficient time and effort studying,
will undoubtedly become so blindingly obvious as to appear trivial.
Thank you... I think. grin!

I could reduce it to the classic "take two aspirin and call me in the
morning."

Ah! You have a Mohican? Or just access to the manual? Mine is missing,
burioed somewhere in my basement; I was fortunate enough to locate a
copy of a GC-1A PDF some kind soul posted online.

It didn't take much effort to scour the web for one (schematic).

You don't need wire to build an inductor. At these frequencies you
can use a capacitor in a Gyrator design.

"Gyrator"? I thought that was the rooftop dance that follows an
antenna adjustment in mid-thunderstorm. grin!

Google led me to the AAVSO site (www.aavso.org) which led me to the
Yahoo VLF_Group. Aaaaaaaaaaaaaaauuuuuuuggggh! A circuit that can
replace capacitors or inductors? My first reaction is "technology
at a level indistunguisable from black magic".

I don't think I'm in Kansas any more.

Gyrators have been around for a very long time, and can be found in a
billion telephones, one probably within reach of you at the moment.
They use telephones in Kansas don't they, Toto? You can build one
with four components (none of them an inductor) to make an inductor
more precisely than you could winding one.

If you truly want to be overwhelmed with the dark arts, try googling
for "magnetic amplifiers." (Art would go ballistic knowing such a
topic was in practice looooong before he left second form.) No tubes,
no transistors, and the orginal "solid state" design. As this may
sound as if it wanders from the subject of RF, add the name Ernst F.
W. Alexanderson to any search.

(On the other hand, I have lots more toys to play with. grin!)

all of the surrounding
EM sets the electroncs in the wire to dancing, but the series RC
blocks those which are wiggling "off-key" (e.g. not dancing at the
"proper" rate of 60kHz).

And this responds to the filtering capacity (selection AND
rejection). This is called "Q" which also serves the yeoman's
task of matching as well

Um. I don't think I ever got past the simplistic "High Q = Good,
Low Q = Evil" stage. Looking back, I can now see cases where an
excessively high Q might be... counterproductive, but as always, it
depends on what one means by "high" or "low" in a given context.

Noted as something else I need to review and not depend on instinct
for.

... (observe the input tank design for the
conventional bands).

Of the five bands (A-E, SW3 positions 5-1), the only one which seems
different is "E", with an additional 130pF cap between the antenna
and the tank circuit.

Is that what you're referring to?

I am merely pointing out the obvious application of a tapped inductor
of the tuned front end serving as impedance match to an high-Z antenna
(the topic of your choice). The schematic abounds in examples. One
need only substitute values to serve the right frequency band - a
simple exercise in reverse engineering employed since Hertz drew a
spark across a gap at the base of a loop.

If you're getting bored, please feel free to skip the following; on
the other hand, someone with access to a GC-1 manual might enjoy my
story...

Yes, your story was/is classic with a beginning, middle, and end. Very
few chroniclers here manage to write with as much clarity. (We get
mostly cheesy attempts with "cliff hangers" serving as examples of
neo-scholarly writing.) Your learning lesson of maintaining the
chassis ground with the trace is classic too. The discovery of
corrosion brings up the common practice of taking ALL the tubes out
and putting them back in to solve problems. Tightening ALL screws is
another hard learned lesson that bench techs either get or don't get.

You probably could have got away with cheaper transistors by also
substituting the bias diodes (56-7s) - but as events bore out, the
transistors were good. If you note the difference between the base
and emitter voltages, there is only about a tenth volt there. If I am
to presume the diode call-out is for an 1N56, it is germanium too.

What is more amazing is this wasn't about the decrepitude of the
electrolytic capacitors which usually suffer with time if they are not
used for a long while.

73's
Richard Clark, KB7QHC