Topband: Twinax

[David Cole]

I am in the process of building a Waller Flag - 
I am going to use Twinax - the Twinax I have purchased has a braiding screen similar to coax.
What do I connect if anything the coax type screening to? 
Do I leave it floating or connect it to one of the inner two wires.
Sorry if its a sill question but I have never used Twinax before and the construction details explain that Twinax is the best choice for the phasing and connection to the two loops being the most durable in respect of weather and UV. Dave g3rcq