Author: SM4RNA Anders - firstname.lastname@example.org
At the input at the bandpassfilter on RF-Unit for MW, 0.5 to 1.6MHz, a 10dB attenuator is located. This attenuator also is a current limiter for the diode D19.
By removing the attenuators three resistors and lead the diode current thru a inductor instead, the increased sensitivity is achieved. But important is to limit the current by changing the value on R119.
To do the mod:
- R116 is exchanged with an inductor of 1mH.
- R117 removed and shorted.
- R118 is removed.
- R119 is exchanged with 150 Ohm resistor.
All resistors are surface mount.
The result is that the sensitivity is increased in the 0.5 to 1.6 MHz range is changed from -103dBm to -112dBm at 12 dB SINAD, 70% AM.
My personal findings are that this do MW listening much more interesting and enjoyable and I have no problems with to strong signal distortion what so ever.