Thread: Vincent antenna
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Old December 5th 07, 04:25 PM posted to rec.radio.amateur.antenna
Yuri Blanarovich Yuri Blanarovich is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 170
Default Loading Coils; was : Vincent antenna


"Roy Lewallen" wrote in message
...
AI4QJ wrote:

Roy, I will definitely be going through those archives. However, we have
seen many antennas in which the entire antenna is wound as a spiral with
a relatively large pitch in order to shorten it. In this case, the entire
antenna could also be considered an "inductor". For that matter, even a
straight length of antenna wire could be considered a 1/2 turn
"inductor". Ignoring the latter extreme example for now, could not the
common spirally wound antenna be considered an inductor that "replaces"
the entire antenna? I'm not saying it is a "good" antenna but it could be
90 degrees long and have the same distribution of standing wave current
as a straight antenna. Also, I wonder if we are arguing semantics over
the definition of "inductor".


Definition is definitely a part of the problem. I don't have so much
trouble with variations of defining an "inductor" as I do with the concept
of "replacing" part of an antenna or measuring an inductor in "electrical
degrees". A straight wire and a coiled wire both have the property of
inductance, but in general a coiled wire will radiate less than a straight
one of the same inductance. The coupling to ground or the other half of
the antenna is also different for straight and coiled wires. So one
doesn't directly "replace" the other. The concept of "replacement" is
overly simplistic and, when extrapolated, can lead to erroneous
conclusions (or in the case of Cecil's and Yuri's theories, multiple and
contradictory conclusions).

Take a look at my 2005 measurements and see if you can do what Cecil and
Yuri failed to do coherently -- use the "replacement" concept and explain
where the missing degrees went.

Roy Lewallen, W7EL


Clouding the issue. "Lost" degrees were not the controversy.

The main argument was (W8JI, W7EL et al) that current along the loading coil
in the resonant quarter wave radiator is constant or very close to, while
(W9UCW, K3BU, W5DXP et al) found that it diminishes toward the stinger by as
much as 40 - 60 %. The rest was nitpicking and drive around the fact trying
to "prove" us wrong or inaccurate or making up "our" theories.

The replacement degrees idea was used to demonstrate the behavior or effect
of the loading coil on the current distribution along the coil and ANTENNA
which is reflective of performance/efficiency of the loaded radiator
(proportional to the area under the current curve distribution).

The "guru" crowd can't seem to swallow this and are harping on this or that,
while any turkey ham can see the effect by grabbing the loading coil and
feeling the heat, more at the bottom than at the top.

The rest of discussions led to better understanding of what is happening in
the loaded element and thanks to Cecil for digging into it and 'splaining
the possible effects.

Which brings me to another subject: standing wave vs. traveling wave
antennas, but that is another story which I would like to get deeper
understanding.

So the argument that missing degrees to fourth decimal point are not there
is just to mask the admission of being grossly wrong and admitting to it and
perhaps even giving some credit where it's due.

Glad that W8JI does not wear inquisitor mantle, or you would have fried by
now Cecil :-)

73 Yuri, K3BU.us