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
Antenna Trap Calculator - Calculator Academy
Bootstrap coax traps for antennas
Making trap vertical antennas
Building Coaxial Traps
An Attic Coaxial-Cable Trap Dipole for 10, 15, 20, 30, 40, and 80 Meters