It helped me a lot to remember that every antenna is, at its heart, a dipole. If your radials are above horizontal (less than 90 degrees to the vertical element), then you’re adding capacitance and making it tune high.
This really helped contextualize it for me, thank you.
I haven't had time to get out there and play with the antenna for a few days. I'll hopefully have some time this coming weekend to play with shortening the radials and seeing about getting a more optimal antenna.
Thanks!
That's what I'm hoping to try this coming weekend. Thankfully the frequency is high enough that it's not difficult to get it a few wavelengths away from anything to remove the chance of interference.