to secure the cross bar to the cemented poles in the ground.. Man, I think you could find one of those.. but, seriously, you could MAKE one pretty easy.. Just need those threaded U shaped thingies, that I'm sure you can get at a fence place (and we even have one here, so you should, as well) and a hunk of metal and a metal drill bit..
If you get desperate, give me the dimensions and I can probably make one for you - provided I can find the U shaped bolts.. I could MAYBE make the bolts, as I do have a tap/dye kit and could thread a U shaped rod - or bend one..
Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..