The CV398 is a tetrode pulse modulator and the construction in this exhibit differs slightly from our other CV398 in that cooling fins have been attached to the support just above the base. The getter holder is near the top of the envelope.
The anode is pressed from two sheets that are stitched together enclosing the support rods. As a high voltage device the top and bottom electrode supports are made from ceramic not mica.
The rounded end of the anode.
The two grids are wound from gold plated wire and fixed to copper rod supports. The notch and peen method of holding the wire can be clearly seen. The notching disc displaces the copper outwards. The wire lays at the base of the notch. The peening roller pushes the displaced copper back into the top of the notch.
The construction is very clearly seen. The anode coating looks to have been added by a spray process. Both grids have cooling fins top and bottom.
The wide glass tube envelope is 64 mm in diameter, and excluding the B4A base pins is 137 mm tall.