NEGATIVE-GRID TUBES FOR PHASED ARRAYS.
Quarterly progress rept. no. 5, 1 Jul-30 Sep 64,
GENERAL ELECTRIC CO SCHENECTADY N Y
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The initial objective of this program is to produce a triode or tetrode capable of providing a cw output of 1000 watts at 50 per cent efficiency at 1300Mcs. Nine L-65 triodes were built and four were available for measurement of r-f performance. In addition, eleven L-65D diodes L-65 triodes with the grid omitted were made for preliminary life test studies. A gain bandwidth product of 7460 Mc was attained at low signal levels in the 1.3Gc region. A new grid support structure was introduced into recent L-65 triodes that reduces the output capacitance this should make possible the attainment of higher values of gain bandwidth product. An output power of 1000 watts cw at 1.3Gc was measured with only 10 watts drive by operating the L-65 with an anode voltage of 2870 volts. Two L-65D diodes were operated on life test for approximately 500 hours before the plate current fell to 1.4 ampsq.cm. It is anticipated that proposed changes in materials and processing will enable the tube life to approach 2000 hours. Author