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 _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
