Andy Ikun, G8LUG wrote in part........
>
>
> Notwithstanding the above. A Mobius shielded loop was constructed using
> 38inch diam. aluminium tube, 3/4inch OD with a split at the top of the loop,
> the inner wire was made from the outer braid of RG58c. This loop is
> effectively 2 turns with a loop inductance of 10uH (res. freq is 5.1MHz).
> This compares to 2.2uH for a 1 turn loop with above size of tube (Res.
> Freq.>50MHz).
>
> The net result was that below 18MHz any gain difference was only due to
> differences in the loop to amplifier match.
>
> Between 18MHz and 30MHz the gain of the Mobius drops off significantly by up
> to 12dB due to the very high loop capacitance.
>
> Both loops had identical nulls.
>
> As far as can see; there is no technical reason to use a Mobius loop for a
> broadband antenna.
>
>
>
>
>
If there is any advantage for a 1.8 Mhz resonance with enhanced capture
area while retaining the special loop nulling characteristics, would it
not make sense to build a bigger loop?
After putting "Mobius" in Google I became even more fascinated to read
that J.S. Bach and Nikola Tesla, both geniuses in their own fields, were
intrigued by the Mobius configuration. I saw where a device called a
Mobius resistor is an electronic circuit element which has the property
of canceling its own inductive reactance. Tesla patented similar
technology in the early
1900s:^<http://en.wikipedia.org/wiki/M%C3%B6bius_strip#cite_note-8>
"Coil for Electro Magnets" was intended for use with his system of
global transmission of electricity without wires. Bach wrote several
Mobius canons that are even more fascinating than the paper strip in art
class. Bach was great at composing "unenliche" melodies where the end
is the beginning and the beginning is the
end.^<http://en.wikipedia.org/wiki/M%C3%B6bius_strip#cite_note-10>
In electronics Mobius considerations appear as:
* as compact resonators with the resonance frequency which is half
that of identically constructed linear
coils^<http://en.wikipedia.org/wiki/M%C3%B6bius_strip#cite_note-11>
* as induction-less
resistance^<http://en.wikipedia.org/wiki/M%C3%B6bius_strip#cite_note-12>
* as superconductors with high transition temperature
My questions are:
(1) would not Mobius theory be applicable to cancelling out inductive
reactance in antenna feed systems such as shunt fed towers or shortened
vertical radiators?
(2) would not a larger sized Mobius loop provide deep nulls but with a
higher gain at 1.8 Mhz yet small enough to allow rotation by a
conventional TV rotators?
Maybe this water has gone over the dam long ago but I am curious if
there is anything there to consider.
Herb, KV4FZ
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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