The Coax trap program computes design parameters for the construction of coaxial traps for HF usage. Typically these are constructed from PVC tube and RG58/59 coax
Coax Traps - Resource Detail - The DXZone.com
To Trap or Not to Trap
Amateur Radio - Multi-band Trap Dipole Antenna
Ham Radio 20 / 40 Meter Short Coax Trap Dipole Antenna | The Wonderful World of Microcontroller!
ON7EQ COAX TRAPS
30- or 20- & 39-Meter Vertical Trap Antenna
trap antennas coaxial trap coax dipole antenna loss resistance
20/40 Meter Short Coax Trap Dipole Antenna - Resource Detail - The DXZone.com
Coax Trap dipole for 12m/17m/30m/40m/80m – IZ7BOJ Hamradio Website