Off-Centre Fed Dipole Question/s

[VK4ADC]

Colin

The proximity of the wire components to the large metal shed roofs will also contrbute extra capacitance (effectively to ground) where in a truly free-up-in-the-air mounting, that capacitance would be far lower.  The effect : lower resonant frequency.
Recall F = 1/2*Pi* square root LC ; where increasing C reduces F

To solve, you either need to raise the height of the OCF substantially (reducing C) or orient it sideways over unobstructed ground (ie no sheds) {reducing C) or, as you have done, reduce the L component - due to length - to shift the frequency upwards.
Unobstructed does not necessarily mean no trees, but a greater distance above ground.(reducing C)

Gotta be reasons why we have to learn electronics / radio theory to qualify for amateur radio licences !!  Just a matter of applying the theory.

Doug