Posted by
Mike Morrow-3 on
Apr 07, 2011; 10:03pm
URL: http://elecraft.85.s1.nabble.com/K1-2973-on-the-Air-Choosing-the-K1-or-KX1-tp6251730.html
>Great to see K1s are still popular. I'm looking to get a K1 or a Kx1.
>I was not sure how well the K1s were selling. Can you tell me why
>you selected the K1 rather than the Kx1?
I ordered my K1 after seeing the prototype at Dayton 2000. It was delivered
(S/N 175) in late November, 2000. In 10.5 years of sales, about 3000 K1s have
been sold. That's one for every business day for the past 10.5 years. I don't
know what the current sales volume is, but the K1 remains firmly after more
than ten years of ownership my favorite QRP rig of all time. Nothing else comes
close.
With respect to the choice of KX1 of K1, as far as ham band CW *RF* performance
goes, the K1 is inarguably superior.
(1) The K1 uses a L-C VFO that is cleaner than the direct digital synthesis
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. According to
reported measurements of the K1 with two-band board, it has better transmitter
spurious output specs than even the K2. The low-pass filtering of the four-band
version is much better than the two-band version. Beware of drawing conclusions
from the QST review of the K1, because they tested a two-band model, which had
the poorer filtering.
(2) The K1 can be placed on any HF band, though Elecraft sells parts for 80m
through 15m only. The KX1 DDS chip is clocked at its maximum rate of 50 MHz,
which limits KX1 frequency coverage to around 20m and lower. The 15m band is
one of the finest QRP bands when open. It's my favorite band. This *alone*
would be enough to make me choose the K1 over the KX1.
(3) The K1 uses a four-pole crystal IF filter, while the KX1 IF uses a three-pole
filter. It's a well-noted characteristic of the KX1 to be able to receive on
*both* sides of a CW signal as one tunes through it because of the lack of
selectivity of its IF filtering. OTOH, since many use their KX1 to receive SSB,
there the three-pole filter is an advantage.
(4) The K1's optional auto antenna tuner tunes a *much* wider range of impedances
than that of the KX1. I'd choose the K1 with KAT1 without any question over any
external tuner. The argument that an external tuner makes it easier to swap filter
boards is specious, since very few K1 owners of the four-band model make such
swaps except rarely.
(5) Most find the continuous L-C VFO tuning of the K1 to be more natural than
the step-wise tuning of the DDS in the KX1.
(6) The K1 has a noise blanker option, while the KX1 does not. I once thought
that the KNB1 wasn't all that useful, but I have some odd type of digital noise
in the area I now live on which the KNB1 is *most* effective.
(7) The K1 transmitter can produce up to seven watts of output power. The KX1
is about half that, if one is lucky.
(8) The K1 case contains a speaker, the KX1 does not. The K1 has plenty of
audio to drive it too.
(9) IMHO, the full-house K1 (with KNB1, KAT1, and four-band board) is easier
(less-tricky) to build than the full-house KX1 with all its options (40/20m with
80/30m option, KXAT1).
(10) I like the front-mounted controls of the K1 more than the top-mounted
controls of the KX1. The so-called "trail-friendly" top control configuration
is, I think, without demonstrable advantage. I've often used my K1 as a
backpack rig.
I personally do NOT like the K1 KBT1. It is a bad idea to have a chemical
corrosion source inside a radio, the pack can't be charged internally, and
the normal K1 speaker is far better than the micro-speaker that comes with
the KBT1.
I do not like the KTS1 tilt stand. It is way over-designed. A simple wire
tilt-bale would be much cheaper and could be premanently stowed under the rig
when not in use, unlike the KTS1.
I think that it is a disservice to supply the K1 without the LCD back-light as
standard equipment. That back-light is a *tremendous* asset to the K1, and it
is, IMHO, a real pain in the butt to back fit to a K1 that has been built without
the back-light.
The KX1 is clearly superior in terms of VFO stability. The DDS is about as
stable as a crystal oscillator. It is superior in its span of frequency
coverage within the limits of the DDS. It can switch between USB and LSB due
to the frequency agility of the DDS as the local oscillator. It has neat
features like audio feedback to controls. It is definitely smaller and lighter.
The KX1 definitely has some positive features that the K1 doesn't have. *None*
of them, except VFO stability, are improvements in *RF* performance on the
ham CW bands. Yet, the K1's L-C VFO is astonishingly and surprisingly stable.
But...if the K1 were not available, the KX1 would be my very next choice for a
QRP rig. It's a very fine and well-designed rig. I would like to see a new KX2
that offered four-pole IF filtering, a DDS that could provide operation at least
up to 15m band coverage, and "from the design stage" coverage from 80m to 15m
without the trickiness of the current KX1 design. And maybe, a little more
versatility in the auto antenna tuner (more like the KAT1). I'd also like to
see an option to choose a case that did not waste volume for a battery pack.
I do NOT want batteries inside a radio. A little external 10-cell AA-holder
works just fine. An option to buy built and tested would also be nice. I've
built many things since I started messing with radio gear in 1964, and today
I don't have the time to waste on mostly mindless, definitely boring kit
building activities. I'd buy such a QRP rig in a heartbeat. If Elecraft doesn't
step up, China will at much lower price. But Elecraft has been pretty much a
K3 enterprise for several years now, just like this list. But many will *never*
want a K3 type of rig for QRP operation.
Mike / KK5F
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