It's semi rigid coax, instead of braid it's solid copper.
I made some of these a couple of years ago, actually they can be quite handy. I wrapped mine in kapton tape, as it's too easy for the exposed copper outer of the semi rigid to touch your circuit inadvertently while you have your eyes turned away looking at the spec an or whatever.
Rather than terminate it yourself, see if you can pick up some ready-terminated semi rigid at a radio rally/ham fest/ whatever it's called in your country. Usually, but not always, they're terminated with SMA connectors, so you'd need an interseries adapter or cable to the N type on your spec an.
Alternatively, RS for example stock RG402 in 1m lengths if you're desperate. Farnell have RG401, RG402 and RG405. Soldering it, particularly the inner, can be an experience by the way, as the dielectric has a nasty habit of melting away, but there maybe someone here who has some tricks to divulge that I'm unaware of.
Howard