My modified traps didn't work. In this video I'll build two new traps and test. Music by Bensound.com 14 mhz trap recipe: 1.5" OD drain pipe 5.25 turns rg58 coax 2" drain pipe knockouts-reversed-for weatherproofing.
Making the trap and exposing the second part of the shield , you can compress it, when the shield fattens you can insert a small screwdriver or forceps or pick on the side of the shield close to the jacket and inserting this tool about a 1cm or so, then start separating the mesh of the screens revealing the underneath polypropylene central tubing/wire and loop it out making a neat shield and central tube/wire separation
is it the termination of the trap? measuring with the leads is probably a lot lower impedence than in the antenna, and the grid dip technique doesn't load the trap much at all. I think.
Making a physical connection to the trap you add capacitance and lower the frequency. A loop only couples the magnetic field . No connection no extra capacitance.
I had the same confusion, when tried directly connect trap coil to S11 NanoVNA. Frequency is lower, I think due to cable's and Nanovna's parasitic capacitance. Measuring with loop is better. Same result also if you connect coil as S21 to Nanovna.
