[Elecraft] KX1 vs. K1

[Mike Morrow]

Ariel wrote:

> I am not sure why nobody mentioned the KX1.  It has 4 watts output,
> 4 bands, weighs next to nothing, 55 mA on receive, and with a 4500mA
> SLA (1 lb) or the equivalent LiFePo which is half the weight...

The KX1 is a really outstanding QRP radio.  But...

1.  It can not cover any ham band higher than 20m due to limitations of
    the DDS circuitry.  As solar activity cycle 24 progresses, these
    are precisely the bands that will provide the best and most
    interesting QRP operation.  The stock K1 is ready with factory
    support for 15m and 17m.  Then, 10m and 12m is easily feasible as
    described here by ones who have developed the necessary KFL1-2 filter
    changes for that.  I'm not sure why Elecraft has never produced
    a 10m/12m filter parts kit during the K1's 12-year existence (all
    the way back to the end of solar cycle 22).
   
2.  Its KXAT1 ATU only creates 124 different combinations of L and C and
    L-C configuration within a very limited range of L and C.  By contrast:

    ATU  L/C Combos     L Range in NL Steps         C Range in NC Steps
   KXAT1     124     0 to  4.5 uH in   8 steps   0 to  140 pF in   8 steps
   KAT1     1020     0 to  4.9 uH in  16 steps   0 to  300 pF in  32 steps
   T1      32764     0 to  7.5 uH in 128 steps   0 to 1300 pF in 128 steps
   KAT3   131068     0 to 17.4 uH in 256 steps   0 to 2600 pF in 256 steps
   KXAT3       ---    Said to be the same as the KAT3    ---

    Thus, even the K1's ATU KAT1 has considerably versatility.

3.  The KX1 has only a three-pole crystal filter.  It is possible to
    hear both sidebands of a strong signal.  The K1 has a four-pole
    crystal filter, and that makes a noticeable improvement.

There are other issues in a KX1 to K1 comparison, but they don't need
discussing now.  From this limited list only items 1 and 3 are important
to me, because I don't use antennas that require a lot of reactance
insertion by a tuner.

If the higher bands are not desired I think that the KX1 is an amazing
rig.  It's certainly the smallest and most energy efficient one that
Elecraft markets.  Its most serious issue, IMHO, occurs at time of
build from the trickiness of backfitting the 80m/30m band parts.  Who
wouldn't want their KX1 to be fully capable of all four bands?

If I couldn't have a K1, I could be happy with a KX1.

Mike / KK5F