"David" wrote in message
...
Jim,

I replaced the ridiculously large 10n with 200pF as suggested. Not a
gnat's wisker difference in the response. Should this have some noticeable
difference ?

Only if the low side RF input grounding makes a bit of difference in the
performance. It seems as though this device is rather numb to doing
anything with the other balanced input.




The Philips app note AN1993 shows a 152 MHz RF receiver using even larger
and more ridiculous 100nF values for the RF decoupling throughout the
circuit. Why would the IC manufacturer use these values ?

Several reasons come to mind. The aforementioned numb unused input. They
found some interesting motorboating (low frequency) proclivities and started
throwing capacitors at it until they found the right value. The
applications engineer was two weeks out of school on his first real RF
circuit.

Jim