so you want to build an EFHW with QRP traps...
This is a very preliminary posting as I seek better understanding of how to post here... Back-story I have been exploring use of tiny traps in an EFHW wire since 2012 as a way to switch bands instantantly while maintaining a 50 ohm load for my KD1JV series transcievers. Below you see one construct using an SMD capacitor and hand wound air core inductor. The inductor is 1/2 inch in diameter. In this case, the capacitor is 100pF and the coil is 24 turns. This yields approximate frequency of 10.0 for the 30M trap. Above you see the components and a completed trap using a toroid inductor and an SMD capacitor. You can see in each photo; how strain relief works. Early attempts to build miniature trapped antennas for use on SOTA (Summits on The Air) all "worked," but with frustrations to tune. The lengths of the wires weren't as expected, and adjusting wire lengths on lower bands (beyond a trap) impacted the higher bands that came before t...