Frank Gilliland ) writes:

... as I write this it occured to me that it might be
easier for Harry to mix the VCO signal down to a frequency where
the average logic IC can work. You don't have to find a prescaler,
and the design's frequency steps won't be limited by the division of
that prescaler. There are various mixer schemes that will result
in the needed frequency. There may be reasons for not doing it this
way, but it may not even be explored because Harry hasn't given this
alternative any thought.

Michael VE2BVW

Hello Michael. Down-conversion has been considered, but quickly dismissed.
The sysnthesiser I need is a tool to be used for a wide variety of projects:
projects that include modulation.

Down conversion of frequency preserves any applied modulation. The prescaler
and subsequent dividers filter out modulation so that a true phase lock may
be achieved. This is especially true with WBFM where the total divide rate
must be greater than 10000 to achieve a phase lock. NBFM, with a minimum
modulating freq of, say, 250Hz, still needs a divider to divide by more than
60.

Down conversion could make a simple synth if modulation were never to be
used. I intend the project area to be both TX + RX, and to become a
"building block" for a variety of circuits.

Anyway, I have received a lot of response. My original question was "is
there a good cheap source of prescalers" (but in a long-winded way) and this
I have received. Many thanks to you and all who have given me positive
suggestions. Unfortunately I will not be melting down horses hooves to make
the glue to bond the home-beaten copper to a board to make the PCB. The only
thin board available would be ready-made plywood, and that would not be
"homebrew" ;-)

BR Harry