Well, no. It's not quite a tube amp, but it sure makes troubleshooting them easier. PLUS, it's got two tubes in there! NO rectifier! This is my first venture into RF tools and it's very exciting. She came in sassy n' nasty. Full of dust, sticky controls, stiff A/U coax, flimsy power cord, you name it. Let's crack her open. Hey, is that a Bugle Boy EM84? Yep!! A nice Euro eye tube. ...and check out this GE 6C4. There's that sticky power switch. No problem. Here's the old RG62 A/U (49 ohm). This unit uses precisely 40" of it to form a precise 1/4 wavelength of the 40MHz test frequency. Not only is the original cable too short, it was haphazardly repaired, so off it goes. The old .1uf cap in the background has a severed lead. I didn't realize this at the time I took the pic, but his time is coming, Old, dried grommets! I forgot to mention those prior. There are 2 x 3/8" grommets on this unit. One for the test leads and the other for the power cord. Both grommets have been replaced, along with the addition of a grounded cord. The new guy. Seshual shocklate. I need to find a little leather handle for the thing. Waiting on the coax and silicon test lead cables to arrive. Opposite the cathode within the envelope is a rectangular fluorescent target. The voltage on the grid directs the angle and size of the electron stream that strikes it, causing it to glow green/blue over various portions of the fluorescent material's length. Once the new coax/test leads are attached, I can align this thing and put it to use. Update soon.