Specifications

From April 2008 QST © ARRL
be custom tailored in eight bands in incre-
ments of 1 dB within the range of ±16 dB.
These adjustments help compensate
for variations in speaker/headphone or
microphone frequency responses or the
acoustical characteristics of the operational
environment to faithfully reproduce the
original audio or to enhance intelligibility.
The transmit voice signal audio equalization
quality can be monitored simultaneously in
headphones without transmitting .
Pseudo-Stereophonic Audio
An “Audio Effects” (AFX) mode feeds
received audio to stereophonic earphones or
stereophonic external speakers with a slight
adjustable lag between left and right sides.
The result is a textured listening experience
that I found considerably less fatiguing than
monaural audio, especially during extended
operating sessions. Having discovered the
AFX, I refuse to turn it off. Both phone and
CW listening is much improved, especially
using stereophonic headphones.
Upgrades and Changes
Elecraft has an established reputation
for listening carefully to user feedback and
in many cases responding to that feedback
by making changes in their products. That’s
been the case with the K3, beginning with
the early beta testers and continuing as ra-
dios are delivered and put into use. The K3,
very largely a software-defined radio, was
designed specifically to allow for changes
through firmware, and a number of well
documented updates have appeared on
Elecraft’s Web site.
Some issues have required hardware
changes. Initial ARRL Lab testing revealed
that transmit-receive turnaround time was too
long for AMTOR operation. Elecraft released
a modification that solved this problem and
improved AGC operation. Another change
(a single capacitor) improved the CW keying
waveform and fixed an issue with shorten-
ing of the first transmitted character. These
changes are included in current production
radios. Owners of early radios should contact
Elecraft for more information.
Initial Lab testing also showed worse than
expected transmitter IMD performance. We
measured third order IMD products at about
–23 dB worst case, and Elecraft indicated
that it should be significantly better. We
confirmed this by measuring transmitter
IMD at the low power amplifier output on a
K3/100, and measured the recorded –27 dB
with their new guidline (below). At press
time we were working with Elecraft to lo-
cate the problem in the review K3/10. We’ll
have more on this in the follow-on K3/100
review. For now, Elecraft recommends that
for best SSB transmit IMD performance on
17 meters and higher, set the power output
to 8 W or less.
I do have a short “wish list.”
 The date formats offered so far are US:
MM.DD.YY and EU: DD.MM.YY. The SI
(metric) format could also be added as an
option — SI: YY.MM.DD.
 It would be great if the Elecraft engi-
neers could find a way to allow auto notch to
work on CW, without notching out desired
CW signals. This is probably a tall program-
ming challenge, but something that many
CW operators would appreciate.
 Nitpicking: I’d like to see a heftier
thumbscrew ground post to accommodate
heavier wire. The Anderson PowerPole
system for the high-current dc power input
has a tendency to disconnect with little
force. That’s only a minor irritant in a fixed
installation, but it could become a more
significant problem in a vibration-prone
mobile environment.
 The K3 Owner’s Manual is available
online. The K3 is complex enough and
changes are made often enough that an
updateable index would be helpful. As firm-
ware changes are made over time, perhaps
new or revised items could be color-coded so
that users could scan the revised index and
key in on the most recent changes.
Final Thoughts
Finishing the K3/10 can be your final
destination, and you’ll have a QRP trans-
ceiver rich in features and basic radio per-
formance. Or you can view it as a starting
point, adding a 100 W amplifier, automatic
antenna tuner, more filters, an interface for
a transverter or separate receive antenna, a
second receiver and more. Full details are
available on Elecraft’s Web site, along with
detailed technical information and explana-
tions of all aspects of the radio’s operation
and a very active user’s e-mail reflector.
Manufacturer: Elecraft Inc, PO Box
69, Aptos, CA 95001; tel [phone];
www.elecraft.com.