A long time ago I built a couple of thru lines using Yorkshire plumbing fittings to use on 23cm and 70cm to check antenna matching. The plan was to make a poor man's Bird Meter but I only ever made one rotatable slug.
I still use one on 13cm. I'm trying to remember where the articles appeared, whether it was DUBUS or Radcom . It would have been the early 80's . Anyone ?