23cm from a 70cm radio (synthesized)
======================

TX
==
Tripple the TX output with a varacter diode.
1293.5 / 3 = 431.16666    not good.

Quadruple the TX output with two transistors.
1293.5 / 4 = 323.375     good, its on a 25KHz channel.

RX
==
Double the 70cm LO and use as LO for 1st mixer:

eg.
1273.5    our Dural repeater

1273.5 - (417.3666 x 2) = 438.76666 (1st IF) 
438.76666 - 417.3666 = 21.4 (2nd IF)
or
1273.5 - (431.63333 x 2) - 431.63333 = - 21.4

Or inject on the high side:

3xLO - 1273.5 - LO = 21.4
LO = 626.05, 1st IF = 647.45

4xLO - 1273.5 - LO = 21.4
1726.533 - 1273.5 = 453.0333 - 431.6333 = 21.4
LO  = 431.63333

4xLO - 1273.5 - LO = -21.4
1669.466 - 1273.5 = 395.966 - 417.3666 = - 21.4

1273.5 - 3xLO - LO = 21.4 
LO = 313.025
1st IF = 334.425

1273.5 - 3xLO - LO = -21.4
LO = 323.725
1st IF = 302.325
================== These last two are usable!!!! ==========