[1000mp] MP vs MkV vs K2

[1000mp@mailman.qth.net]

Tom, W7GT wrote:

"Where are the non-linear products in the MP being generated?  In
particular, are they in the early stages, prior to the 8.2 and 455 IF
filters?"
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3rd-order IMD (IMD DR) products are the result of unwanted signals (along
with the desired signal) getting inside the various filters in a receiver
and thus producing spurious responses.  In the MP (and most other modern
receivers), these filters are the "roofing" filter in the early receiver
stages, the 1st IF xtal filter, and the subsequent IF xtal filter. 
Because the unwanted signals we talk about when we are referring to IMD
DR and BDR are normally outside of the IF xtal filters (but inside the
roofing filter), I would say that 3rd-order IMD "birdies" are most often
generated in the early stages of the receiver.

The ARRL has traditionally tested IMD DR (and BDR) using an unwanted
signal spaced 20 kHz from the desired signal.  Tom, W8JI finally
convinced them that 5 kHz spacing would be more meaningful, so now they
include IMD DR and BDR values for both spacings.

73, de Earl, K6SE