PVC doesn't block RF, but it does influence it.
Yes, you must trim from both ends of the dipole evenly.
And, as said by others, anything near it, especially the ends, will affect tuning.
My suggestion: do you have a fiberglass step ladder you can mount it on for tuning?
Even bolting it onto a 2x4 with U-bolts around the bottom PVC insulator can help keep it away (above) the roof line/gutters, etc.
My antenna was only leaning against the house for a photo. Photos of it in the air shows the PVC bottom cut much shorter and on the end. I didn't realize it would confuse you.
Yes, you must trim from both ends of the dipole evenly.
And, as said by others, anything near it, especially the ends, will affect tuning.
My suggestion: do you have a fiberglass step ladder you can mount it on for tuning?
Even bolting it onto a 2x4 with U-bolts around the bottom PVC insulator can help keep it away (above) the roof line/gutters, etc.
My antenna was only leaning against the house for a photo. Photos of it in the air shows the PVC bottom cut much shorter and on the end. I didn't realize it would confuse you.