Weird SWR problem that I’ve seen before!!!

[M0GVZ]

With RG8 or RG213 large coax I’ve always done my connectors that way. I fold back the shield over the insulation. Leaving about 1/4” of the white dielectric. I screw on the pl259 until I see the white through the holes in the connector. Solder the center connector. You could be right though maybe there is an issue with the shield connection. I’ve got a 50’ piece of rg8x I will put in place of the RG213 and see what happens. Might get some answers.

No that's not how you do it. With proper decent PL259s that actually fit properly and are silver plated and not chrome plated so you can actually solder the braid to the shell without melting the center insulation you cut off the outer insulation leaving the braid as it is when the insulation is peeled off all the way to where you cut the center insulation down for the center conductor. You then solder the braid through the holes in the PL259 to the shell.

This link here has the recommended stripping lengths for the Amphenol 83-1SP, a PL259 for RG8/RG213 I cannot recommend highly enough. Any PL259 that's made to spec should be the same.

https://www.amphenolrf.com/library/download/link/link_id/593880/parent/083-1SP/