Re: Loading Coils; was : Vincent antenna


"Yuri Blanarovich" <K3BU@xxxxxxxxxxxxx> wrote in message
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"AI4QJ" <nospam@xxxxxxxxx> wrote in message
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I would assume if I
was as far off in what I think the topic is supposed to be, you or others
would have jumped in to tell me AND TOLD ME WHAT THE ACTUAL CONTROVERSY
IS ALL ABOUT.

Some more about it at
http://www.k3bu.us/loadingcoils.htm
besides Cecil's pages

The main argument was the current distribution along the loading coil in a
resonant quarter wave radiator. I and bunch stated that there is a drop
along the coil, W8JI and bunch argued that not, that EZNEC "proves" it
(using lumped inductance model). Nice to see W7EL coming around and
recognizing difference between modeling the coil as a solenoid and lumped
inductance.
The net result is the overall current distribution along the radiator,
which reflects efficiency and is significant when elements are employed in
the arrays of loaded antenna elements.
The rest is just digging deeper into the pesky electron behavior.
It would be interesting to get report on W7EL visit to W8JI.

Yuri, www.K3BU.us

Excellent information. The current along the coil reduces as it "replaces" a
section of an equivalent straight antenna section in degrees. This is true
even to the extent as existing current distribution in the section where the
coil is placed. I can see how someone in the 1950's might assume that
current in = current out (kirchoff) and not consider the degrees electrical
length occupied by the coil but ARRL should not be propagating such
information today. We know better now and besides, it is plain and simple
"intuitive" once you know that current changes along the electrical "degree
length" in an unloaded antenna, the same should happen in the degree length
loaded coil.

Thanks for taking the time to show the root of the controversy.

Also, as indicated, the pictures do say 1000 words and it also looks like
W8JI ended up agreeing with you after you pointed out the same effect at
"ON4UN's Low Band DXing", 3rd Edition, on page 9-34.

de AI4QJ


.

Relevant Pages

  • Re: Current through coils
    ... re-shrinked, the insulation on the coil from the bottom up, while ... insight into the workings of the loaded, shortened radiator or element. ... difference in RF current across the antenna loading coil." ... The loading coil, as it turned out, had ...
    (rec.radio.amateur.antenna)
  • Re: Current across the antenna loading coil - from scratch
    ... use electrical degrees to 'splain the behavior of coiled antenna wire? ... I can see how problems could arise going by the length of coil ... wire length in degrees only. ... gonna make a hoot's worth of difference in the design of mobile whips. ...
    (rec.radio.amateur.antenna)
  • Re: Current across the antenna loading coil - from scratch
    ... compact inductor would have negligible current difference at each end, ... only a long straight wire would act like the "missing antenna". ... For example if the coil is a very large area single turn, ...
    (rec.radio.amateur.antenna)
  • Re: Current across the antenna loading coil - from scratch
    ... compact inductor would have negligible current difference at each end, ... only a long straight wire would act like the "missing antenna". ... For example if the coil is a very large area single turn, ...
    (rec.radio.amateur.antenna)
  • Re: Current through coils
    ... I have done a number of "peer reviews" for IEEE and AIP publications ... The Tesla coil crowd seems to contain an unusually large fringe. ... merely discuss the actual current in the antenna. ... not a traveling wave or a standing wave. ...
    (rec.radio.amateur.antenna)