"Michael Black" wrote in message
xample.org...
On Sun, 15 Jun 2014, gareth wrote:

If one were to be building an RX around a scrapped Xtal filter,
that would certainly resolve the SSB bandwidth requirement,
but what of CW?

How about then using one of the USB / LSB CIO Xtals as a
crystal-plus-phasing control to circumvent the paying out
of shekels?

But then what do you use for the BFO?

The other CIO XTAL VXO'd into place/

Cascading the filters makes sense. The single crystal filter will be
nice and sharp, but have a lousy skirt. Keeping the SSB filter inline
ahead of it means that will limit the skirt selectivity of the overall
receiver.

Actually that's a better idea than mine, because I was considering
switching the single Xtal in place of the filter, and results in a much
simpler switching requirement.

Other ideas snipped because involved the spending of money


A bit fiddley in the switching from USB / LSB / CW though,
but the other CIO should be VXOable to pull it into range.
(ISTR that VXO statistics suggest a shift of 1kHz per MHz
should be possible)

That just sounds messy. YOU complicate things so you can use the BFO
crystal for the filter, then have to make do with another BFO crystal.


Well, I've _SHED LOADS_ of switches in a junk box going back 50 years :-)

But thinking about your critique, and musing upon the various QRP designs
using only one transistor for numberous roles in TRX designs, then it
becomes
simpler. have two separate CIO. One is configurable as a filter or as an
oscillator,
and the other as a CIO or a VXO.

As I said, just musing along with some ideas and your input is most welcome.