Bob [K5QWG],
So Why . . . Choose a Slinky over Stranded Copper Wire
for a Shortwave Listening (SWL) Antenna ?
Yes the Signal capture Area is only 15 Feet vice the 64 Feet of Wire
wrapped-up in the Slinky.
But when compared to a Single Copper Wire that is also 15 Feet Long
the Metal Slinky due to it's Coiled-Up-Wire {Spring} Shape has a
cross-sectional-area that has the electrical appearance of a Thicker
(Much Larger Wire) and thus is the better RF Signal gatherer.
Note - That the Slinky has the added 'dimension' of Thickness about
2.75 Inch Diameter vice about 1/8 Inch Diameter for the Copper Wire.
FWIW - The same could be said for an Antenna Element that is
made of an Inch Diameter (1") piece of Copper Pipe that is 15 Feet
Long over a piece of #14 AWG Stranded Copper Wire that is also
15 Feet Long.
Either way the Slinky or the Copper Pipe has a Larger-Physical-Area
and Greater-Surface-Area for the RF Signal Electrons to be gathered
'in' and and 'on' then the same length {long} of Wire.
So Why . . . Choose a Slinky over Stranded Copper Wire for a
Shortwave Listening (SWL) Antenna ? ? ?
- - - CAUSE IT'S A SLINKY !

)
yes i am a little bit slinky - iane ~ RHF