A Low-Noise Microwave Quadrupole Amplifier

Experimental results on a low-noise microwave amplifier operating at 4137 Mc are described. At a gain of 19 db the measured double-channel noise figure is 0.79 db, corresponding to an effective temperature of 58°K ± 10°K. The effective beam temperature is 25°K ± 10°K. The noise bandwidth between points 3 db down from the optimum is 32 Mc. The tube operates at 10 volts and 27 μa and requires about 150 mw of pump power. The dynamic range of the amplifier is about 100 db.