20M Window Loop Stealth Antenna Construction Guide
Build a discreet 20-meter window loop antenna using a 4C65 toroidal core.
Description
A 20-meter window frame stealth antenna, based on a design by PD7MAA, utilizes a single 620cm wire loop for discreet installation. The feeding mechanism employs a 4C65 toroidal core, where the antenna loop functions as a single-turn secondary, and the feedline wraps twice. Tuning is achieved via a 30cm twisted wire stub, allowing for SWR adjustment within the 20m band.
This design is specified for QRP operation, with a maximum power limit of 25 Watts to prevent core saturation or arcing. Wire selection recommendations include thin, insulated copper wire (0.75mm to 1mm) for blending with architectural elements. The guide focuses on practical construction steps for a low-profile 14MHz antenna.