(click for larger image)

KD1JV

 Rock-Mite Audio Filter

builder: Rod N0RC
builder caution, mount C2-5 last

NOTE in this photo (and the larger one) R2/R3 and R5/R6 are mounted in the wrong posistions R2/R3 must be swaped around, same goes for R5/R6, per QRP-L posting from Steve, KD1JV.
Test Set-up (NOTE after correcting R2/R3 and R5/R6 as noted above the 1Meg resistor called out in the photo below was NOT required.)
Filter OUT: NO limiting resistor as shown above.
the red line is from the "peak hold" feature of Spectrogram		 Filter IN: R2/R3, R5/R6 in correct position
Note gain supplied by the filter/click image for larger image.
Filter OUT: WITH limiting resistor as shown above.
the red line is from the "peak hold" feature of Spectrogram		 Filter IN: R2/R3, R5/R6 in wrong position
Note gain supplied by the filter