"Scott Dorsey" wrote in message
...
gareth wrote:
"Scott Dorsey" wrote in message

"Single signal reception" to me would imply a narrow-sloped bandpass
filter but it sounds more like marketing than engineering.

Perhaps you, as indeed do others seem, are trying to interpret a technique
from
the 1930s and 1940s in terms of the multi-pole Xtal filters that are the
norm today?

Well, yes. That is the point of this thread, isn't it?

No, it isn't.

I have a junk box going back 50 years from which I intend to make the sort
of RX that I dreamed of as a teenager in the 1960s, on the basis that if I
do
not make use of all those museum bits and pieces, the executor of my will
will be likely to bin the lot.

I am inspired by the ham-bands only Eddystone EA12 and am making slow
progress
in a DIY effort to manufacture the gears for the dial drive and am now
considering
the manufacture of a Catacomb along the lines of the National NC100X.

One technique from those pre-mechanical, and multi-pole or monolithic
Xtal, filters was to use a _SINGLE_ crystal early on in the IF chain, and it
is that
single crystal together with its phasing control that interests me at the
moment.