VWS DC Receiver Low Noise Amplifier

Getting back to working  on the VWS DC Receiver, I decided to combine the AF mplifier and the low noise amplifier on the same board to cut down on size.  Because I have been thinking about having separate Low Pass filters for SSB and CW, I will put them on another circuit board instead of with the LNA.

To better match the low impedance of the of the Low Pass filter, the LNA uses a common base amplifier feeding a common emitter stage.  To provide power supply decoupling, Q2 and the associated components are commonly called a cpacitance multiplier.  This provides a capacitance value to the input stage of approximatly the value of  C3 times the gain of Q2.

This configuration along with the LM-386 stage has over 90 dB. total gain, therefore a separate gain adjustment is added to prevent possible overload distorton.  

I decided to make the board MUPPET style, instead of using through hole.  To reduce the board size I installed the resistors vertically.  I

etched a board using toner transfer, and dipped it in some 'liquid tin' to provide a better soldering surface than just bare coppper.  One of these days I will try one using the CNC router to see if there is much of a difference in the quality I can get.

Waiting on an assortment of inductors, that seem to be taking forever to get here so I can finish the LowPass filter board.