[Elecraft] Why buy a KX2/KX3 compared to a KX1/MTR3B in a QRP portable scenario?

[Mike Morrow]

Barry wrote:

> ...I would have preferred the K1, but I don't believe Elecraft is
> selling that anymore.

The K1 is still sold...see http://www.elecraft.com/k1_page.htm .  The K1 remains an excellent small CW-only transceiver.  However, the four-band KFL1-4 filter board has been unavailable for a couple of years.

The original posting in this thread contrasted the KX1 vs. KX2 or KX3.  If RF performance mattered, where the K1 is clearly superior to the KX1, the 16-year-old K1 deserves honorable mention among small QRP transceivers:
(1)  The K1 uses an LC VFO that is cleaner than the DDS frequency generation scheme of the KX1.  This reduces transmitter spurious output, and improves receiver performance because fewer spur frequencies are part of the local oscillator signal fed to the front-end mixer.
(2)  The K1 can be placed on any of the HF bands, although Elecraft sells parts for 80m through 15m only.  The KX1 DDS chip is clocked at its maximum rate of 50 MHz, which limits KX1 highest frequency coverage to around those of 20m band.
(3)  The K1 IF uses a four-pole crystal filter...the KX1 IF uses three-pole.  This makes a very noticeable difference in selectivity.
(4)  The KAT1 produces a larger number of configurations (1020) of impedance than the KXAT1 (124).  (It's of note that the KXAT2 produces 32764 different network configurations, 264 *times* the number of the KXAT1.  The KXAT3 produces 131068 configurations, 1057 times the KXAT1.)
(5)  Many find continuous K1 LC VFO tuning more natural than step-wise KX1 DDS tuning. 
(6)  The K1 has a noise blanker option...the KX1 does not. 
(7)  The K1 transmitter can produce up to seven watts of output power.  The KX1 is about half that...at best. 
(8)  The K1 case has a speaker...the KX1 does not. 

OTOH, the KX1 is clearly superior in terms of VFO stability.  It is superior in its span of frequency coverage within the limits of the DDS.  It can switch between USB and LSB receive mode due to the frequency agility of the DDS as local oscillator.  It has neat features like audio feedback to controls.  It is smaller and lighter.

With respect to the KX1 vs. KX2 or KX3, the gulf in capability and performance is so great as to render the question absurd.  The only advantage to the KX1 over the KX2 is that Elecraft provides a schematic for the KX1...something that very noticeably withheld for the KX2 and its accessories.  That implies the customer is an "appliance operator".

Mike / KK5F