> That places the majority of those products outside the
> passband of your
> sideband filter on BOTH sidebands.
It looks to me like one group of IM3 products will be mostly
OK, except carrier offset causes a gap.
That group will miss close-spaced mixing of IM3 products
however, so it is incomplete. One group of IM3 products
will be totally missed and that group would be the group
that contains the close-spaced mixing of closer spaced
high-frequency tone IM products.
Say you has a 2000 and 3000 Hz tone mixing. The closest IM
products would be 1000 Hz above the highest tone and 1000Hz
below the lowest tone. Neither would be detected with a
sideband switch.
As for testing on the air I see one huge problem. The noise
window is wide and there probably is a lot of junk from
other things in the passband. This is a test that can easily
convince people they have no problem when they do for
multiple reasons, and it can also do the opposite if the
receiver is operated in a way that makes it limit
performance. This is especially a problem if someone with a
wideband ESSB signal would use that method.
http://www.w8ji.com/mixing_wide_and_narrow_modes.htm
73 Tom
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|