Posts and wires for supporting a loganberry

[suecruh]

I want to erect 2 posts with wires in between to support a loganberry. They will be freestanding so will need braces on the inside of each post to stop them being pulled together. My question is 'what angle do I need to cut these brace supports at and how deep do I need to set them.
Many thanks
Sue

[welsh brickie]

you can use 3x3inch x 8ft posts and concrete them 2 feet deep you wont need a brace