Abstract: An aqueous alkaline solution comprised of 5 weight % to 10 weight % KOH, 5 weight % to 15 weight % KF and 10 weight % to 20 weight % K.sub.3 PO.sub.4 is used as an electrolyte in a secondary electrochemical cell wherein the active material of one of the electrodes is a zinc-active material.

Abstract: A radar reply transponder for use with existing radar tracking systems wherein a reply pulse is generated and trasmitted in response to an associated interrogation pulse. The reply pulse is delayed in time and offset in frequency by a precise amount with respect to the interrogation pulse, but it is nevertheless phase coherent therewith so as to preserve the required Doppler frequency information and thereby permit accurate velocity measurements. Phase coherence is effectively maintained by utilizing a single continuously operating local oscillator for down-converting the received interrogation pulse to an intermediate frequency as well as up-converting the signal information to provide the delayed and frequency offset reply pulse. The precision frequency offset is obtained by switching in an additional reactance element in the oscillator-determining circuitry during the time up-converting is being effected.