[Elecraft] K1 and KX1 Compared

[Bruce Prior]

The Elecraft KX1 is best understood as a smaller and generally more refined 
version of the K1.  In many respects the KX1 is superior, but the K1 also 
has its advantages.

Let's start with aspects where the two rigs are quite comparable:

In the K1, zero-beat spotting can be accomplished with the receiver unmuted 
using menu item StP, or with the receiver muted via menu item StL.  For 
routine operation, I leave the K1 menu set for StP to make that function 
readily available.  Zero-beat spotting is most convenient on the KX1 using 
the SPEED function, during which time activating the keyer doesn't transmit 
RF.  The KX1 also has the StL and StP menu items which can also be used for 
zero-beat spotting, but in both cases the receiver is muted.

The basic keyer features of the K1 and KX1 are identical, offering 
non-volatile mode A or B keying and with non-volatile programmable keying 
speeds between 8 and 50 WPM.

Although the K1 has an optional 10-element internal tuner, and the optional 
internal tuner for the KX1 has only 7 elements, the two are approximately 
equal in usefulness, since the K1 tuner requires operation over a wider 
frequency range.  Both rigs are considerably enhanced by these well-designed 
options.

Because of fine engineering and very detailed instructions in the manuals, 
both the K1 and KX1 are easy to build and either one would be an appropriate 
choice as a beginner's kit project.

Here are features which are superior in the K1 compared with the KX1:

The basic K1-2 offers a choice of CW portions of any two bands between 80 m 
and 15 m (excluding the USB 60 m allocations, of course), or four bands with 
the K1-4 or an optional module which is designed for 40, 30 and 20 meters, 
plus a choice between 15 and 17 meters.  The 2-band or 4-band modules can be 
swapped so that the K1 will cover six bands total.  I have my 4-band module 
configured for 40, 30, 20 and 15 m, and my 2-band module includes 80 and 17 
m bands.  In addition, the K1 firmware also allows 160 m operation with the 
2-band module and some operators have implemented it, including W3FPR.  See 
Don Wilhelm's and Wayne Burdick's postings on this subject in the archives 
of the Elecraft e-mail reflector for 21 November 2003, available through the 
<http://www.elecraft.com> website.  The basic KX1 covers the 20 m and 40 m 
bands, and the 30 m band can be added with a tiny and inexpensive optional 
module which is permanently mounted between the main board and the control 
panel.  So, for the number of amateur bands covered the K1 is better.

Both RIT and XIT are available on the K1, whereas the KX1 sports only an 
RIT.

Power output is easily programmable from the K1 front-panel from 100 mW to 7 
W.  The KX1 power output can be controlled via an accessible trimpot using a 
tiny screwdriver from approximately 100 mW to about 4 W, depending on the 
input voltage used.  The KX1 power trimpot is not designed to be adjusted 
frequently.

The K1 has a nice-sounding built-in speaker which is muted when a plug for 
an external speaker or headphones is inserted.  The KX1 is designed 
principally for use with headphones, but the audio level is sufficient for 
using an external speaker.  I intend to carry a speaker with my KX1 in a 
backpack to free me from having to be tethered to the rig while operating 
it.  It is frequently convenient to listen to a radio while carrying out 
camp chores.  At home I very seldom use headphones with the KX1.

The K1 has provision for an optional noise blanker against ignition or 
similar noise sources, whereas the KX1 has no noise blanker option.

The well-designed 4-pole crystal audio filter in the K1 has three 
programmable steps, a better design than the 3-pole crystal audio filter of 
the KX1 with its analog front panel control pot and noticeable audio 
attenuation at the narrow end.  A slight nod has to go toward the K1 in the 
audio filter department, but the KX1 filter is convenient and wide-ranging 
enough for normal CW operation or for listening to AM or SSB transmissions.

The audio stage automatic gain control of the K1 can be turned on and off, 
whereas in the KX1 the AGC is always active.  This is really a safety 
feature in the KX1, however, since that radio is designed principally for 
use with earphones.

Both the K1 and KX1 have two beacon-capable message memories, but the K1 has 
a 90-character capacity in each memory, whereas the KX1 memories holds up to 
48 characters each.

The following are the characteristics where the KX1 outshines the K1:

Designed from the start as a trail-friendly radio, the KX1 is lighter and 
less bulky than the K1.

The K1 has no audio feedback interface system.  The basic KX1 has a 
comprehensive and programmable audio feedback interface system which is the 
best I've ever experienced.  With a smaller encoder knob installed, the KX1 
is an ideal radio for a totally blind operator, and KX1 audio feedback is a 
great backup for sighted hams as well.

The K1 uses an analog varactor diode tuning system which yields a maximum 
total range of about 150 kHz per amateur band, whereas the KX1 has a far 
superior DDS rotary encoder tuning system which not only allows full amateur 
band coverage, but non-transmitting receive coverage considerably beyond the 
specified amateur bands.  In addition, the KX1 tuning speeds are 5 kHz, 1 
kHz, 100 Hz and 10 Hz per encoder step.  This makes large or small frequency 
excursions very convenient with the KX1.

The K1 can be equipped with a versatile, but heavy optional wide-range 
tilt-stand, whereas the controls-on-top KX1 design make such a tilt stand 
completely unnecessary.

While the K1 has a single-step RF attenuator, the KX1 sports a more 
versatile analog RF gain control.

The only K1 option which I would not recommend is its 8-cell optional 
internal battery holder.  The reason I don't like it is that it is very 
awkward to access in the shack, to say nothing of the field.  A 6-cell 
internal battery holder comes standard in the basic KX1.  It is considerably 
more convenient than the K1 version.  Its only disadvantage is that with 
only 6 cells, the KX1 produces lower output power than when using a 12 to 14 
Vdc external power source.  The KX1 internal battery holder can be loaded 
while operating from an external power source, and the radio will draw from 
whichever source produces the higher voltage.  For outdoor operation, I 
prefer to carry 6 AA lithium cells inside the KX1 but normally operating 
with an 8-cell external AA holder available from RadioShack.  In cold 
weather or on lengthy trips I always use AA lithium cells in the external 
holder.  For an overnight trip in the summer, 8 alkaline AA cells would do 
fine to power the KX1.

The KX1 is very well designed for CW-to-LSB or CW-to-USB cross-mode 
operation, while on the K1 cross-mode operation is only practical on the 17 
m band, and there only with non-standard LSB transmissions.  Since my life 
was once saved by just such a cross-mode contact, I'll admit a personal bias 
strongly in favor of the KX1 because of this feature.

Only on the 7.1+ MHz band are a few shortwave broadcast stations receivable 
with the K1, whereas the KX1 has extensive shortwave receive coverage, 
especially with the optional 30 m adapter installed, and the KX1 produces 
surprisingly good audio quality for SSB or AM reception.

The K1 has a scrolling non-illuminated liquid crystal display which is 
difficult to read in some conditions, but the KX1 has a variable-brightness 
low-current LED display which is not only easy to read in varying 
conditions, but it can be programmed to turn off after a period of 
inactivity.

The K1, like the K2, comes equipped with a hard plastic tuning knob, while 
the plastic tuning knob on the KX1 is rubber-ringed for better grip, 
especially using gloved fingers.

The K1 requires the use of an external key or keyer, but optional detachable 
iambic keyer paddles are available for the KX1.  The KX1 is also compatible 
with an external key or keyer.

A frequency memory on the K1, if it could be called that, is only possible 
by retaining the position of the 10-turn tuning potentiometer on a given 
band.  The KX1 has one non-volatile last-stored frequency/mode memory per 
band plus three more non-volatile frequency/mode memories per band.

No lighting is available on the K1, but an independently-switchable LED 
logging light on the KX1 can also be used as an emergency flashlight.  Some 
users may wish to replace the standard white LED with a red one to 
discourage neighboring insects from joining the party for CW lessons.

The base model K1-2 (2-band version) price is $289 + S&H; the K1-4 (4-band 
version) is $349 + S&H.  The K1 with all options starting with the K1-4 is 
$621 + S&H.  The K1 with all options starting with the K1-2 is $631 + S&H.  
The basic KX1 costs $279 + S&H, or $456 + S&H with all options.

I own both a K1 and a KX1 and I don't intend to sell either one, but if I 
had to choose between them, I'd go for the KX1.

72,

J. Bruce Prior N7RR
Kairos Research
853 Alder Street
Blaine, WA  98230-8030
360-332-6046

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