Steve wrote:
>... how about a K1 design using the DDS of the KX1, full
>coverage and the options of the K1 ????
I really like Dave Benson's pioneering work in QRP rig design by using a DDS chip to *directly* generate the receiver local oscillator and the transmitter oscillator frequencies for mono-band rigs five years ago (I own the DSW-20, -30, and -40 rigs). The KX1 does basically the same thing in a great three-band design with added functional versatility. The frequency stability and agility are fantastic.
But there are some disadvantages to using a DDS in these functions in terms of generated spur frequencies that degrade receiver performance and transmitter spurious output specs. Power consumption for a DDS chip can be significant, though I think Elecraft has a minimal power use chip in the KX1. Most low cost, low power DDS chips don't like to be clocked over 50 MHz, with an output frequency of about one-third that, so it is difficult to generate clean output for ham bands higher than 20 meters. In addition, DDS tuning is step-wise versus the continuous tuning of an LC VFO.
I'm happy that the K1 design uses the cleaner LC VFO and crystal hetrodyne oscillator approach to generate the operating frequency.
73,
Mike / KK5F
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