Traps

Homebrew your own inductors - Can’t find the inductors you need for an antenna, a tuner or amplifier? Build your own—it’s easy! By Robert H. Johns, W3JIP

7 Mhz traps for W3DZZ

Antenna Trap Calculator - Design your own antenna trap online

Coaxial Traps for multiband antennas - A new perspective on the analysis and design of this popular antenna element. By Karl-Otto Müller, DG1MFT

Homebrew your own inductors  ^pop - Can’t find the inductors you need for an antenna, a tuner or amplifier? Build your own—it’s easy! By Robert H. Johns, W3JIP

7 Mhz traps for W3DZZ

An Improved Multiband Trap Dipole Antenna - This improved multiband trap dipole introduces a new trap design and a change in trap location. The antenna features double-coaxial-cable-wound traps having lower reactance and a higher quality factor (Q) than earlier coax-cable traps by W8NX

Antenna Trap Calculator - Design your own antenna trap online

Bootstrap coax traps for antennas - Analysis of an antenna trap where a coil is formed of a length of coax cable, the outer conductor of one coax end is tied to the inner conductor of the other coax end, and the remaining connections form the terminals for the trap.

Building Coaxial Traps - This page describes the design and construction materials W8WWV used to build a coaxial cable trap. A coaxial cable trap is a parallel resonant circuit that is usually inserted in an antenna element to enable multiband operation.

Building traps with coax cable - Tips on how to build a trap using common coaxial cable and coax trap software, by F5JTZ in french

Coax Traps from a Modeling Perspective - About Coax Traps, NC4FB examine the operation of coax traps through modeling.

Coaxial Traps for multiband antennas - A new perspective on the analysis and design of this popular antenna element. By Karl-Otto Müller, DG1MFT

CoaxTrap - This program let you design of antenna trap using length of coaxial line wound as solenoid on a coil former.

Easy tuning an building of traps  ^updated - A new and simple method for tuning traps. You need 2-3Watt of your TRX and two homemade coupling coils by DK7ZB

Homebrew traps - Traps can be one way round multiband coverage without the need of an atu. Learn how to homebrew your own traps

How antenna traps work - An interesting article about homebrewing antenna traps for multiband antennas by VE3GK

Multi Band Antenna Traps - These devices are called Traps, but they are actually more like frequency sensitive switches. They are parallel resonant, high Q, tuned circuits which provide a very high impedance at their frequency of resonance.

PA3HMP Antenna Traps - An original way to build antenna traps

To Trap or Not to Trap - An interesting article on traps, pros and cons of trapping by W4RNL

TrapDip - This program let you design and performance of 2-band trapped dipole antennas including trap design.

Trapped antennas - ARRL index of document about trapped antennas and notes on traps usage

Traps for 160 meters band - Extending a 40/80 trapped dipole to 160 meter band

Traps for 40/80 m dipole  ^updated - I6DVX article on hoembrewing traps, using vetrnonite instead of common coax cable.

Troubleshooting Traps - This article refers mainly to the old Cushcraft 1/4 wavelength AV series of antennas (12AVQ, 14AVQ etc) hence the references to radials. The R series (R5, R7 etc) are 1/2 wavelength antennas, and the radials are NOT 1/4 wavelength resonant.

Tuning HF Coaxial Antenna Traps - The problem with making your own trapped HF antennas is usually getting the coaxial traps tuned to frequency.

VE6YP CoaxTrap - 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