Test instrument provides a random noise signal over audio, long wave and middle wave frequencies.
A filamentary diode valve 6D4 in a magnetic field generates a noise signal that is amplified by two 6AQ5 stages.
A 0.3A, 4V ballast maintains the 6D4 filament current constant.
A 115NO3OT thermal delay valve allows the noise diode to heat up and settle first.
Ranges: 20 kc/s, 500 kc/s, 5 Mc/s.
Output 0.0001, 0.001, 0.01, 0.1, 1.0
Meter FSD 5V in 0.2 V steps.