Here is a add from a supplier of the antenna.

SP-1000

HIGH PERFORMANCE TWIN 1/8" SQUARE COPPER WIRE COIL,
FREQUENCY COVERAGE 26-31MHz,
"SWR LESS THAN 1.5:1 1.5MHz SPREAD"
STANDARD 3/8" x 24 THREAD
OVERALL LENGTH 54" ( WHAT not a 1/4 wave only half the length )
Dam that makes it 1/8 wavelength in the physical length.
No where does it say 1/4 wave equivelement. The only thing that could be
called a 1/4 wave antenna is a is a 1/4 wave antenna.
Thats just another marketing tool to cause more confusion in the antenna
world.