Abstract: 1. An anti-jam device for conical scan tracking radar comprising:an input circuit to a conical scanning radar antenna for transmitting sigs into the atmosphere, said signals appearing effectively unmodulated when viewed from a target;a radar receiver for receiving echo signals from said target;a modulator circuit coupled to said input circuit; andmeans coupling said receiver to said modulator circuit to apply said received echo signals to said modulator circuit as a divider of radio frequency energy whereby the amplitude modulation produced by the conical scanning radar antenna on the transmitted signals appears effectively eliminated when said signals are viewed from said target.

Abstract: 1. A limiter circuit for limiting the voltage amplitude of a circuit comping:A circuit to be limited with respect to a fixed potential thereof;An electron emission device having a control electrode and two conductiton electrodes, one of said conduction electrodes being coupled to said circuit to be limited and the other of said conduction electrodes being coupled to said fixed potential;A Zener diode having its anode connected to said other conduction electrode of said electron emission device and its cathode coupled to said fixed potential; andA voltage biasing source from said fixed potential connected to said control electrode of said electron emission device to establish a voltage amplitude limit for said circuit to be limited.