Duo-Spiral Hetro-Loop Antenna Radio Units Inc.; Maywood, IL, build

MAGNETIC LOOP 40M - 10M Built by 2E0ERO

Fenu-Radio - Antennen - ALA1530 - RF Systems - HDLA - Dressler - Mini Whip - AOR

Build an Active AM Broadcast Ferrite Antenna /w Phase Loop

Detailed dimensions of the dual-loop antenna unbent into a planar

Antenna

Spiral loop

File:Vintage Duo-Spiral Loop Antenna By Radio Units, Inc., Maywood, Ill., Circa 1920s (14969446205).jpg - Wikimedia Commons

Detailed dimensions of the dual-loop antenna unbent into a planar

Implantable Rx loop antenna (a) Geometry, dimensions: LR=WR=12mm

Small Loop Antennas - IW5EDI Simone - Ham-Radio

Radio News 1924 10 R, PDF, Mail

Spiral loop

RadioDigest 24-11-15, PDF, Loudspeaker

Implantable Rx loop antenna (a) Geometry, dimensions: LR=WR=12mm