Maker's Name: 
Huggins Labs, Inc., Sunnyvale, California
Where made: 
36 × 5.5 × 7 cm

Amplifier of UHF signals in the 1 GHz region, such as satellite communications.

The input signal travels along a wire helix in an axial magnetic field. An electron stream travels the length of the tube coaxially with the helix.

The voltage creating the electron stream is such that the velocity of the electrons is equal to the axial velocity of the signal on the helix.

The magnetic field of the helix, being variable, bunches the electrons ie the signal modulates the electron beam. The longer the helix, the greater the modulation. The output signal is drawn off at the electron beam collector electrode.