RX small preamp with 2SC5551

This is very simply low noise preamplifier module with 2SC5551 transistor based on W7IUV design. You can use it as high IP preamplifier for RX antennas, buffer amplifier or small driver. Gain is up to 18dB and there is also built in variable ATT. You can easy set gain as high as you need! Amplifier has got low noise - lower than 2 dB up to 50 MHz and around 2,2 dB at 150 MHz. As well you can set right transistor bias with multi turn potentiometer. Two relays offer bypass switching if there is no power supply.

Main functions:

• Info:
  • Broadband: 0.1 MHz to 60 MHz (11 dB @ 150 MHz)
  • Very high IP3
  • Good gain up to 18 dB
  • Low Noise Figure (NF) 1,2 to 2 dB (2,5 dB @ 150 MHz)
  • High output power up to 26 dBm
  • Variable ATT for gain 0 to 18dB
  • Bypass relays
• You can set transistor bias as you need by trimmer
• High quality relays with TWO contact parallel
• SMA connectors
• DC patch cord
• PCB size 50x50,4 mm
• Available as
  • ASSEMBLED and tested

Parameters:

• Info:
  • NPN transistor 2SC5551A
  • Supply voltage 12 - 14 V
  • BIAS current 10 to 70 mA
  • Supply current up to 180 mA include relays!
  • Gain: up to 18 dB
  • Low Noise Figure (NF) 1,2 dB (20 mA 50 MHz)
  • Low Noise Figure (NF) < 2 dB (60 mA 50 MHz)
  • Low Noise Figure (NF) 2,3 dB (20 mA 150 MHz)
  • REAL IP3 34 dBm

Use:

• High IP, Low Noise RX preamplifier - RX antennas
• Buffer amplifier
• Driver amplifier

The measured values

Gain 10dB 0,5MHz to 50MHz

Gain 15dB 0,5MHz to 50MHz

Gain 18dB 0,5MHz to 50MHz

Bypass 0,5MHz to 50MHz

Available also in enclosure (KIT/assembled):

Download

RX small preamp ver 1.1
Schematic and board pic	sch	brd
We believe open source is a better way of doing things. View and download the Shield Schematic and PCB files. The hardware designs are released under the Attribution-NonCommercial 2.0 Generic