Re: OT: High Frequency coax?? Copper tubing??
Here's a representative link for the information you're looking for:
There's lots more. This was simply the first one google tossed up. It is great stuff provided you don't want to bend it more than once. Though rebending used cables is OK. The solder filled braid "RG402" has become my standard cable for anything above 1 GHz. I've made a couple of H field probes from a used piece of high grade stuff.
Connector quality on Chinese ebay jumpers is rather variable. I've been documenting my efforts in this thread:
I will be supplementing the TDR results with 8753B/85046A testing soon now that I have an APC-7 cal kit and adapters.