[Elecraft] slinky warts

[James Hammons]

       I received a new copy of the 19th ed of the ARRL Antenna Book
about a week ago,  On page 6-25 they have a section on short
continuously loaded verticals.  Your slinky antenna would seem to be
of this type.  From what they say performance could be comparable to
full size antennas.  You might note they say you need a rod or disc at
the end to reduce Q.  The slinky alone doesn't seem to have this.
They cite low radiation resistance and bandwidth. =20
       On page 6-22 they show reduced size dipoles using linear
loading which means the wire runs back and forth instead of being
stretched out.  Again they say this can be comparable to a full size
antenna.  One made with three wires would only be about 19ft for
20meters.  This seems to be a good candidate for condo and apartment
balconies.  Again the radiation resistance is low requiring matching.
        I was disappointed that they didn't show any modeling of these
antennas.  Has anyone done any modeling of these short antennas, or of
shortened hat loaded antennas like the Force12 sigma's.  Force12
doesn't show any patterns for these antennas and that makes me wonder
about their actual performance in spite of their great reputation.  =20
      =20