Ramsey Electronics PR20 - Manual (Page 3)

PR20—3
CIRCUIT DESCRIPTION
L1 and C2 form a tuned input filter for the preamp to reject out-of-band signals. The 3 db
bandwidth of this filter is 6MHz. L1 is adjustable for peak performance. The 2SC2498
transistor is a bipolar silicon NPN low noise UHF/VHF amplifier in a TO-92 case suitable for
service up to 5 GHz, with maximum device dissipation of 600 milliwatts. Q1 has a very low
noise figure, determined by the bias established by R1 and R2. The actual circuit is about
as simple as they come. Maximum gain and freedom from oscillation are accomplished by
the quality of workmanship in parts installation and I/O connector wiring