Ramsey Electronics PR20 - Manual (Page 2)

PR20—2
INTRODUCTION TO THE PR20 LOW NOISE PREAMPLIFIER
A “preamplifier” gives an initial boost, measured in decibels, to the level of a signal before it
is further processed by tuned circuits, filters, amplifiers, mixers, detectors, or other circuit
stages. Preamps may be designed for either RF or audio use and may be either tuned or
broadbanded.
The Ramsey Low Noise PR10, 20, and 40 Preamplifiers for 144, 220, and 440 MHz,
respectively, differ from our popular SA7 and PR2 broadband preamplifiers in that these
models include high-Q tuned input circuits to pre-select the desired frequency range,
restricting the strength of other out-of-band signals. Also, the microwave transistor is biased
for best low noise performance.