[Elecraft] Where's the KX1 feedback?

[Lyle Johnson]

> > The KX1 does USB and LSB by using high-side or low-side
> > injection from the DDS.  For 15m operation, it would need to
> > output at ~16 MHz and ~26 MHz.
>
> A DDS-based CW transmitter does not need a transmit mixer, and from the
> schematics, the KX1 is no exception. For 20 meters operation, the DDS
> generates 14 MHz directly, and for 15 m, it would need to generate 21
> MHz directly.

For receive you need to adjust the DDS for the IF offset, which is ~4.9 MHz.
So, the DDS has to switch, on 20m for example, from 14.something on transmit
to 9.something or 19.something on receive. It is the receiver injection
frequency that is the problem.

-Lyle