[INRAD] FILTER CASCADING

[Charlie Mazoch Jr.]

Hello Earl:
 I just finished cascading the second IF filters in a FT-980 Yaesu and 
am very pleased with it's outcome. It is a world apart from just 
utilizing an extra filter. Dual cascaded filters sure do sharpen and 
deepen  skirts when compared to using a single filter. George sells a 
cascade board which has adjustable amplification added to compensate for 
any losses when cascading filters. When in transmit the second filter is 
switched out for original sounding audio. I used the OEM filter and 
added a 2.1 Khz Inrad in cascade. George had built the boards and 
circuit for use on the FT-920 Yaesu but I found it to work just fine in 
my application. At present I'm awaiting a 4 Khz roofing filter to add to 
the FT-980 1st IF. Then there are projects in the design stage to add 
the same filtering to an Icom 756. I also own a Yaesu FT-847 I'd like to 
make more selective by utilizing a 4 Khz roofing filter. I believe Inrad 
is the old Fox Tango reborn. George is very knowledgeable on his or any 
other mods concerning filtering and  it's associated circuit design. He 
is also very pleasant to do business with.   73's  Charlie  W5VIN