the coupled helices being disposed coaxially around one another

Full Title

Details of transit-time tubes of the types covered by group H01J25/00 > Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy > to or from the interaction circuit > for linking interaction circuit with coaxial lines; Devices of the coupled helices type (H01J23/46 takes precedence) > the coupled helices being disposed coaxially around one another