Very interesting and explains 40m folded back as it's adding capacitance between the two conductors since they are still insulated they act like a top hat.
My brain is about to explode from all this scientific frequency talk. Since Radio Shack is out of business I can't even go buy an antenna locally. haha
Another factor that wil make your resonance lower is insulated vs bare wire. The insulation will lower the velocity and the resonance. Then the velocity slowing effect will show when you build and test a twin lead J-pole antenna then stick it inside a PVC pipe to make it self supporting and discover that the PVC lowers the resonance!
It isn't velocity Ed. Velocity is only a thing for transmission lines. Insulation on the wire doesn't change the speed of the electrons, but it does change the amount of capacitance in a given length of wire. You're changing the dielectric constant of the insulator in the construction. Same thing happens when you put your wire j-pole inside of PVC. You've put a much better dielectric material between your conductor and the Earth - drastically changing the inherent capacitance of your circuit.
And all this time I thought the “ velocity factor” of a single wire (e.g., dipole) was the speed that those dits and dahs (insert favorite mode) attained before they fell off the end of the antenna... like lemmings into the sea (end of wire effect?). Good talk anyway. Thanks for another ham oriented video amongst the wood. Oh -and sorry you cut your antenna too short (or at least that’s what makes me search for a logical explaination through reasoning and formulas). 73’s W2RSB ):
