> Ah, if only we could get a K1 with a DDS VFO! Absolutely NOT!!! True, a DDS VFO adds crystal-like frequency stability, and frequency-change agility. But it also adds many spurs on its output that increase spurious emissions on transmit and spurious output of the receiver local oscillator to degrade receiver performance. (All this assumes that DDS output is being used in the signal paths directly, as it is in the KX1, rather than to synch a phase-locked loop voltage controlled oscillator.) If good RF performance is an important criteria, one will always be forced to choose an LC VFO over a direct use of DDS in the signal path.
Traditionally, DDS chips have been power hungry, although the KX1's AD 9834 is very good in that area. Its maximum clock frequency of 75 MHz (earlier, 50 MHz) limits it to frequencies below 25 MHz (earlier, 16.7 MHz), which is a big reason why few DDS QRP rigs were designed for 15m coverage. The LC VFO makes a much better performing and cleaner K1, as long as it has good stability. The K1's LC VFO is amazingly stable. Its continuous tuning is far more natural and less fatiguing than the step incremental tuning of a DDS rig like the KX1, IMHO. I would NOT purchase a K1 that had been modified to use the output of a DDS directly. > Everything else remaining the same, because it is the perfect radio! Well...let's just say it's the best QRP radio of its size and power consumption. Mine is almost 14 years old and I will never get rid of it, unless someone sneaks in and changes it to DDS! :-) > I have a KX3, but I miss my K1, should have kept it. Exactly so. I'll be ordering a KX3 soon...but my K1 stays forever! 73, Mike / KK5F ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
