I’m the proud father of
three Elecraft radios (K2
#1770 born in 2000, K3 #2887
born in April 2009, and K3
#1297 of uncertain vintage)
plus a KPA500 amp, W2
wattmeter and P3 panadapter.
built most of them from kits,
partly to save a few $ but
mostly because I enjoy making
things. Like Heathkit years
before, the Elecraft kits are
excellent, providing detailed
all hardware and electronic
components for the K2,
pre-made modules for the K3),
and if needed responsive
online support from
engineers plus the community
of builders and fans.
Everything worked first time
and is a joy to use. The
thrill of hearing the first
callsigns on a receiver
you’ve just finished is
hard to beat - actually
working DX with a homebrew
transceiver is superb. These
are not beginners’
projects though. The K2 took
me a month of evenings to
build and the K3 an intensive
day. While the K3 is a
(basically assembling the
case and plugging in
pre-built modules and circuit
boards), learn to solder
properly before you try building the K2!
KPA500 QSK amplifier
- The K2 suitcase set
- The K3, a serious radio for serious contesters, DXers and DXpeditioners
Both my Elecraft radios are physically compact and lightweight. The K2 is about the size of a car
radio. The K3 is about the size of a large box file, similar to other mid-sized ham transceivers but
considerably smaller and lighter than the FT1000 etc. Pelican waterproof cases or aluminium flight
cases with foam inserts are a good way to protect them both when travelling, and are small
enough to travel in the cabin as hand baggage ...
My QRP ‘suitcase set’ consists of the K2, some antenna wire and string, a Palm mini paddle, pen
and paper, and a small switched-mode PSU to recharge the rig’s internal 12V SLA battery, carefully
packed into the foam insert and ready to go in an emergency (living on a major fault line in one of
the world’s most active earthquake zones, that’s no joke). As well as in the shack on decent
antennas, I’ve used the K2 portable stylie on picnics and holidays in France, Brussels, and New
Plymouth feeding wires tossed over convenient lighthouses etc. The auto-ATU will tune almost
anything but wire dipoles, doublets, verticals or loops make more efficient antennas than random
lengths of wet string.
I own the 100W PA kit for the K2 but haven’t found the time to build it yet. QRX. I might build it into
the separate EC2 enclosure, leaving the base K2 as a more portable QRP radio.
The K3 is more sophisticated than the K2 with a fully digital IF and AF using DSP for demodulation,
noise reduction, AGC etc., on receive and digitally generating the modulated waveform on transmit.
Mine has the second receiver option (giving SO2V at last, if not SO2R!). I can monitor the beacons
and CW end of 10m simultaneously. It is handy to be able to pick out callers in a pileup and figure
out where the DX is listening (in one ear) while simultaneously listening to the DX (in the other ear).
The K3 has a true diversity mode with two independent receivers, phase locked by dint of sharing a
common reference oscillator. Using a 30m fullwave loop on the subRX in my right ear and the
beam, vertical or dipoles on the main RX feeding my left ear, I find diversity mode is worth about
3dB due to the loop partially filling-in QSB dips on the main antennas. Signals sway from side to side
in my head, floating across the gap between my ears (no comments please).
Whereas the K2 covers the main 9 shortwave bands 160-10m, the K3 also covers 60m and 6m,
with an optional internal 2m transverter.
The K3 is not perfect however. Check out the spectrum anomalies on this BeaconSee output for
example: the horizontal white and pinkish lines are most likely artifacts of the K3’s DSP:
By comparison, the following screenshot from my TS850 shows no such obvious artifacts:
There are a few K3 mods and add-ons:
Solve a nasty transmit spur on K3s released in mid-2009 by removing a single capacitor.
Rather than constantly reaching over to the rig or adding some sort of external switch box for
the DVR/CW memory buttons (M1-M4 plus the REC button used to interrupt sending),
Logger32’s Radio Control Panel lets us define up to 36 macros. The commands to trigger and
abort the memories are easy enough, while more complex ones to set up split etc. just take a
bit of patient experimenting to get right.
The Elecraft KAT500 500W auto-ATU is cool if you use 500W or so. Not so cool for our 1kW
limit in NZ.
Connecting the K3 to your PC
The K3 comes as standard with an RS232 serial port through which it can communicate with
logging software, passing information such as its frequency and mode in either direction. RS232 is a
well-defined standard. The K3 has a 9 pin RS232 connector.
If your PC has an unused real RS232 serial port, you simply need a suitable cable to connect it to
the K3. However most of us need a USB/RS232 serial converter gizmo since modern PCs have
USB ports but no RS232 ports. Some hams will insist that you need a particular chipset in the
converter to avoid problems, but I guess I have been lucky: all mine have worked OK. USB/RS232
converters are cheap as chips so don’t worry about chipsets, just take a gamble. Buy one and try it
. If you are highly risk-averse and have the $$, simply buy the one from Elecraft.
Here’s how to connect your PC to your K3 (I will assume you are using a USB/RS232 adapter on a
Windows 7 machine - if not, your mileage may vary):
Before you plug your USB/RS232 adapter in, install its driver from the CD that came with it.
Usually, just putting the CD in the PC will get it to start the install. [You might be lucky and
not need a driver install if it is already included in Windows. Some of them are but they tend
to be generic drivers while the one provided by the manufacturer with the adapter is more
likely to work properly.]
Now plug the USB/RS232 adapter into the PC’s USB port (any one should work). Wait a
moment for the PC to recognize it and find the driver you have just loaded. A pop-up
message should appear bottom right of the desktop saying something like “New USB device
found – installing driver” and then shortly after “USB serial adapter installed”.
Now figure out which serial port the adapter is using: open Windows Device Manager. The
easiest way is to hold the Windows key and tap the Pause/Break key, then Device Manager is
the top left option. Click it to run it. One of device types listed should be “Ports (COM & LPT
)”: click the little arrow to the right of that line to open up a list of all the serial ports on your
machine. One of them will be the USB/RS232 adapter you have just installed, usually called
something simple like “USB Serial Port (COM2)”, in which case COM2 is the number you need
for step 6 (keep a note of it). [If you have several ports listed and don’t know which one it is,
you can simply try them all by trial-and-error, or unplug the USB/RS232 adapter and wait a
second to see which one disappears, then plug it back in to make it reappear.][If your
USB/RS232 is using a COM port number above COM8, you will have to reconfigure it to be
able to use it in N1MM – this is achieved in Device manager by right-clicking the com port line
and selecting Properties à Port settings -> Advanced, then choose a COM number in the range
1-8, one that isn’t already in use by another device. Hopefully you won’t have to do this.]
Plug the RS232 end of the USB/RS232 adapter into your K3: there is only one RS232 port on
the K3’s rear panel.
Configure the K3’s serial port: press and hold the K3 menu button, then find the RS232
settings by turning the VFO B knob. I normally select the maximum speed (38400 baud).
Also configure the PTT/CW key setting to be rts-dtr (you will be using the dtr setting to send
CW now, but the rts PTT setting can be used to put the rig in transmit for audio data modes
later if you want to play with RTTY etc.). Tape the Menu key to exit the settings. [Optionally
you can put the K3 into TEST mode by holding the mode up button, so that you can test the
CW sending in a moment without actually transmitting. TX will flash on the display while in
TEST mode. Hold TEST again later to put the rig back into normal transmit mode.]
Start your logging software and get it to connect to the K3 - instructions for Logger32 and
N1MM follow below.
Configure N1MM to connect to the K3
In N1MM, go to Config -> “Configure ports, Mode control, Audio, Other” then open the
For the COM port which the USB/RS232 adapter is using, select the radio Elecraft K3, and
then select (tick) the CW/Other box for that port.
Click the Set button for the COM port and then configure the port to match how it is set up on
your K3 i.e. port speed (38400), Parity (N), data bits (8), stop bits (1), DTR/pin 4 (CW),
RTS/pin 7 (always off), radio nr (1). Deselect (untick) all 3 PTT options (VOX on the K3 does
that) and Allow ext interrupts. For completeness, select two radio protocol None, foot switch
None and CW/PTT port addr 2F8 (these work for me but I’m not entirely sure what they do!).
End the N1MM configurator by clicking the OK button once for the Config ports panel and once
more for the Configurator. It will immediately try talking to the K3. Hopefully, it will not give
you an error message but will bring up the normal N1MM screen, now showing the frequency
and mode from the rig (in the title area of the main data entry window). Success!
Now try it out: hit the F1 key to send a CQ message in CW – assuming you are running a CW
contest in N1MM and it is talking to the K3 OK. Hit the Escape key to interrupt the sending.
There are lots of things you can do to make N1MM send the correct serial number in the
exchange, automatically send CQs on a loop etc. etc. – check the N1MM documentation for
Configure Logger32 to connect to the K3
- In Logger32, go to Setup -> Radio -> Radio 1
Select the correct Com port, baudrate (38,400),
radio (Elecraft K3), databits (8), stopbits (1),
Set the polling interval to about 200mS (polls
the radio 5 times a second) - more often if you
like, less often on a slow PC.
Check (tick) just two options: Use narrow CW
filter and Radio changes frequency when Mode is
Click Apply. Logger32 will begin talking to the K3
and should identify the current frequency of VFO
A (it ignores VFO B) in the title bar of the main
log entry window. [Note: Logger32 doesn’t
always show the frequency of my K3 -
sometimes I have to QSY the K3 just a bit to
get it to pick it up. I’m not sure why that is.]
If you wish, confirm that Logger32’s CW sending
function (click the Morse key icon to launch it) sends CW as it should (in the keyer setup
dialogue, check Share radio serial port for CW and Slow typing).
Note: observant viewers may have noticed that I use Com 2 in N1MM but Com 4 in Logger32. The
reason is that for everyday logging, I use LP Bridge to replicate the real K3 port (which is Com 2 on
my PC) across a number of virtual Com ports for Logger32 (on Com 4) plus various other utilities
such as MMVARI. I can’t get N1MM to work reliably with LP Bridge so for contests I shut down LP
Bridge and connect N1MM directly to the K3. It’s one less thing to go wrong, and avoids any delays
and glitches when keying the K3 from N1MM’s memories.
Useful K3 features
Triggering the K3’s voice memories from N1MM contest logger
If you have the neat little K3 DVR option installed, N1MM’s superb contest logger software can be
configured to trigger the K3’s voice memories using the PC’s function keys to send the relevant K3
In N1MM, open the SSB memory config screen (Config --> Change CW/SSB/Digital Message
Buttons --> Change SSB Buttons).
In the .WAV File column, instead of the file name of a .wav file on the PC, enter the
appropriate K3 command string to play the relevant memory:
The four “CATA1ASC” commands shown in this screenshot play the K3’s voice memories M1
through M4 using function keys F1 through F4 respectively. You can send other commands to
the K3 in the same manner - check the K3 Programmers Guide for the available commands
Click OK to save the config.
Test it at this stage if you wish by hitting F1 to F4 in N1MM (assuming you have already recorded
messages on the K3). Note: it’s best to put the K3 into TEST mode to avoid actually transmitting
the messages on air until you are ready to work people!
Now configure the radio port to send PTT commands: this will allow you to interrupt the memory
currently being sent with the PC’s ESCape key - dead handy if you press the play button just as
someone comes back to you:
Go to the port config (Config --> Configure Ports, Telnet Address, Other)
Identify the COM port you use to control the K3 from N1MM and click the SET button for that
Turn on “Radio PTT via command” by putting a checkmark in the box.
Click OK to come out of the config menus.
If my instructions don’t work for you, try N6ML’s instructions instead.
“Instant CW split” macro
When I come across a juicy morsel of DX operating split, I use the following key macro to set up
the typical “Up 1” CW split instantly, making use of the K3’s sub-receiver. It is configured on one of
the K3’s front panel keys so a single tap on the button, plus a bit of time to tune around and find a
good frequency to transmit in the pileup if he’s not listening exactly 1 kHz up, is all it takes. No
messing around with the split button, turning on the subRX, resetting the VFOs etc. - it all happens
automatically, quickly, correctly and reliably every time:
1 2 3 4 5 6 7 8 9 10 -----------11-----------
RT0 = Turn RIT off just in case it was set previously
XT0 = Turn XIT off just in case it was set previously
FR0 = Turn normal split mode off, just in case it was set previously
DV0 = Turn diversity receive mode off, just in case it was set previously
BW0100 = Set the filter bandwidth to 1 kHz to focus-in on the DX, cutting off most callers in
the pile [you may prefer even narrower settings, such as BW0060, but I tend to reserve
narrow filtering for the few times when I really need it. If you normally operate SSB, use a
wider setting such as BW0180 or BW0200 or more, otherwise you won’t be able to copy the
SWT13 = A>B [first time] i.e. copy the DX frequency from VFO A to VFO B
SWT13 = A>B [again] i.e. copy the mode, filter settings etc. from VFO A to VFO B
UP4 = Moves VFO A up by 1 kHz [note: 4 is a parameter not a frequency - see the
programmers’ guide for other possible split values. “Up 1” is just a starting point that works
for most CW DXers. SSBers usually split ”Up 5”, so use UP7 instead. Either way, be prepared
to tune around for the best frequency on which to transmit]
SB1 = Turn on the SubRX to listen to the DX, now he is on VFO B
BW0280 = Open the filter on VFO A to 2.8kHz so I can listen to more of the pileup in the
hope of finding someone working the DX
MN111;MP002;MN255 = Listen to audio from VFO B in both ears with VFO A in my left ear
only [MN111 is the code for the audio mix function; MP002 is a parameter; MN255 ends the
code. The parameter options are MP000 = A B (great if you are able to concentrate on either
ear) MP001 = A AB (giving VFO A priority over B by being in both ears) MP002 = AB B
(giving B priority) and MP003 = AB AB (both VFOs in both ears). Naturally, this command
only works if the subRX is turned on!]
- Optional extra LKB$ = Lock VFO B to avoid me accidentally tuning away from the DX station
by knocking the VFO B knob [I prefer not to lock the VFO so I can follow the DX around if he
should QSY, without having to release the lock, but this means I must be careful not to knock
the little knob]
Notice that I do not use the K3’s built-in split mode to operate split. I listen to the DX on VFO B and
transmit on VFO A. Advantages of this ‘reverse split’ configuration:
QRQ QSK still works fine, whereas split operation disables QRQ mode.
I’m tuning around the pileup with the main VFO knob, leaving my little knob well alone.
I can use the CWT tuning indicator to zero-beat my transmitter more accurately on other
I'm tempted also to turn on the attenuator to reduce the audio QRM from the pileup, using RA01;
but meanwhile I simply use the AF/SUB knob (with the K3 configured for SUB AF = BALANCE) to
reduce the volume of VFO A relative to B. [Arie PA3A proposed a command to reduce the audio
from A or B by 6dB without having to fiddle with the mix settings and AF/SUB knob, so he can
command it from N1MM during a contest, but for now the fiddling works for me. Others use
external audio switching and mixing boxes to combine different rigs/receivers.]
By the way, Logger32’s “radio control panel” lets us send arbitrary commands to the K3 through
the serial port. Logger32 also has the brains to recognize split-frequency DXcluster spots (such as
when someone ‘helpfully’ spots some juicy DX with something similar to “up 2” or “QSX 14027” in
the comment), sending the split-frequency macro to the K3 as it QSYs to the spot. But, as always,
don’t forget to LISTEN FIRST and find the best place to transmit. Don’t be a cluster crab.
“Instant CW pileup” macro
The following macro is handy for me to start ‘listening up 1’ with a single button press, when I
generate a CW pileup of my own:
1 2 3 4 5 6 7 8 9 10 11 -----------12----------
SWT13 = A>B [first time] copy the frequency from VFO A to VFO B
SWT13 = A>B [again] copy the mode etc. from VFO A to VFO B
UP4 = Move VFO A up by 1 kHz
FT1 = Turn split on (SWH13 would do this too)
DV0 = Turn diversity off
SB1 = Turn on the SubRX to keep an ear on my TX frequency, while also listening to the pileup
RT0 = Turn RIT off
XT0 = Turn XIT off
LK$1 = Lock VFO B, allowing me to tune through the pileup on VFO A without the risk of
accidentally knocking my TX frequency on VFO B
BW0270 = Open the filter on VFO A (the pileup) to 2.7kHz to catch callers who are not right
on my announced split freq (I can always narrow the bandwidth on A using the width control if
the pileup gets too big, but mostly I prefer to pick out individual callers ‘by ear’)
BW$0050 = Narrow the filter on VFO B (my TX frequency) to 500Hz to avoid hearing split
callers too close to me, while still listening for those who fail to split at all plus any kops who
QRM my TX freq
MN111;MP002;MN255 = Listen to the pile in both ears, plus my TX frequency in the right ear
Here’s a key macro to clear any split, locks etc., resetting the K3 instantly to my default unsplit
1 2 3 4 5 6 7 8 9 10 ----------- 11 ----------
SWT11 = Swap VFO A with VFO B [since I have usually been listening to DX on VFO B with the
reverse split setup, and want to continue listening to the DX when unsplit]
BW0270 = Set VFO A to 2.7kHz bandwidth, my preferred bandwidth for all modes
SWT13 = A>B [first time] i.e. copy the DX frequency from VFO A to VFO B
SWT13 = A>B [again] i.e. copy the mode, filter settings etc. from VFO A to VFO B
FR0 = Turn off split
SB0 = Turn off subreceiver
RT0 = Turn off RIT
XT0 = Turn off XIT
LK0 = Unlock VFO A
LK$0 = Unlock VFO B
MN111;MP001;MN255; = Set the audio mix to A AB [so if I later turn on the sub-receiver, I
will hear it only in my right ear]
- Optional extra DV1 = Turn on diversity mode - useful when I have a diversity antenna anyway
Audio mix macros
These simple key macros set the audio mix without having to navigate the CONFIG menu options:
SB1;MN111;MP001;MN255; turns on the subreceiver and sets the audio to A AB (A priority)
SB1;MN111;MP002;MN255; turns on the subreceiver and sets the audio to AB B (B priority)
Turning off the subreceiver returns the rig to the normal A A setting, with ‘stereocode’ effects if AFX
is on. This makes quite a difference over plain monophonic audio on CW. It’s cool. Try it! In the
K3’s menu (tap the menu button), set AFX MD to dELAY 5 for the most pronounced effect.
Other K3 features and tips
If, like me, you use Logger32 with the K3 and if, also like me, you prefer to use the K3 in CW-REV
mode rather than CW, there’s a simple workaround to get the K3 to stay in CW-REV when you
click on a DXcluster spot - see my Logger32 page for details, also how to get Logger32’s DVK
function to trigger the K3’s DVR memories.
The K3’s DVR memories work well on SSB and CW but I find the user interface confusing ... cue the
helpful DVR operating instructions by KE7X.
Here's a tip for AFSK RTTY users on the K3. The tones transmitted by the PC should match the
tones expected by the K3, particularly if you have the TX audio filters turned on (it’s a menu option)
. If they don't (for example if you try to respond to a signal too high or too low in the audio
frequency range), the PC audio will trip the VOX but little if any RF will emerge and the K3
sidetone/monitor will be quiet or silent. I discovered this when changing to a new sound card. I'm
now using a second card to separate PC bleeps, MP3s, YouTube audio etc. from my pure RTTY
tones. While playing with the settings, I discovered the K3’s PITCH setting in AFSK modes. The low
tones (915Hz) sound nicer to my CW-tuned ear than the default high tones (2125Hz), so I set the
K3 to 915. I neglected to change the MMTTY setting - largely because I tend to use "NET" in MMTTY
to set the transmitted tones to match the received tones, which lets me 'tune' on RTTY just by
clicking in the middle of RTTY sigs on the MMTTY waterfall (I hope my convoluted description makes
sense!). With NET off, MMTTY defaults to high tones which the K3's line input evidently filters out
(although the VOX presumably triggers on raw audio before the filter).
Having subsequently set the 915Hz tones in MMTTY, I saved the MMTTY profile to stop it reverting
to the high tones every time MMTTY is re-started (same applies when using MMTTY within
Logger32: set the tones then save the profile).
According to someone on the Elecraft reflector, the K3’s numerous birdies can be significantly
reduced if not eliminated by carefully dressing the cables within the case, knocking out the
remainder using the clever LO displacement function in firmware. With a quiet receiving location,
birdies on the high bands are the most annoying so perhaps I should give that a try, next time I
have the case open.
K3 REF CAL re-calibration
Re-calibrating the K3’s VFO frequency is easy if you can have a high quality frequency reference
such as a GPS-trained Rubidium source, or can hear one of the standard frequency transmissions
such as WWV or WWVH:
Turn on your K3 and wait a good while (e.g. a couple of hours) for the rig’s internal
temperatures to stabilize in your normal shack operating conditions. Don’t even bother trying
this if your shack temperature fluctuates wildly while you are operating.
Tune to your frequency reference in CW mode. You should hear a carrier at roughly the same
pitch as your CW sidetone (if you are uncertain of that, hold the SPOT button to hear your
sidetone and check its pitch). Pick the highest frequency reference you can receive a strong
enough signal to discern its pitch clearly (e.g. 20MHz) as that accentuates any error
compared to using lower frequencies (e.g. 10MHz).
Hold the Mode-down button to switch to CW-REV mode on the other sideband. If the pitch
changes, your VFO is off frequency. Switch back and forth between sidebands a few times to
be sure you can hear the difference.
Hold the MENU button to go into the main configuration options.
Turn the small VFO B knob to find the REF CAL option and
make yourself a little note of the
current value -
well the last 3 or 4 digits at least.
Turn the VFO knob to adjust the REF CAL value up or down by a few Hz or tens of Hz - you
should hear the pitch change a bit as you do so.
Flick back and forth between CW and CW-REV to hear whether the pitch is the same. If the
difference is greater than before step 5, you may have moved the VFO CAL the wrong way,
so go back to the original value and shift it a bit the other way. [You may also have gone the
right way but too far: don’t worry, you’ll get there in the end!]
Repeat steps 5 and 6 repeatedly, making smaller moves of the VFO CAL as you get closer the
point at which you can no longer hear any difference in pitch between CW and CW-REV.
You’re done! Tap MENU to exit the menu.
If you are not good at discerning small differences in pitch by ear, or want to be even more
accurate, use audio spectrum analysis software such as SpectrumLab (ideally using a fine resolution
setting such as FFT input size of 16384) to compare the pitch more accurately between CW and
CW-REV. WSJT-X also offers a frequency calibration mode. You should be able to get to within 2 Hz
of the true value, with care down to within 1 Hz.
If you screw up completely, reset the REF CAL to the value you noted in step 5 and either give it
another go or just “live with it”. Minor frequency errors really don’t matter at all in normal ham
usage. I re-check my K3 every few months, and usually come up with the same REF CAL value of
49.379.781 (on one of my K3s - others differ). I only bother with this rigmarole at all because I
want to report the actual frequencies of HF beacons as accurately as I can, partly so I can identify
them later from the same information having tuned them in carefully using the K3’s CWT function.
K3 + Sennheiser headset
Santa brought me a fabulous Christmas present one year, a
Sennheiser PC 230 headset
. I have
been a fan of Sennheiser headphones for about 25 years. I had been happily using a pair of
Sennheiser PX 100 lightweight folding headphones to listen for several hours a day to my K3. The
audio quality and comfort were excellent, while the open style means I could hear things happening
around me, such as someone knocking at the door. The PC 230 basically adds an electret
microphone on a little adjustable boom so I no longer need to use the old Kenwood handheld mic
for my rare forays onto SSB. A switch in the boom turns the mic on as it swivels down into place.
The mic has a noise-cancelling pickup on the outward side of the boom, and the headphones have
a rotary volume control neatly built into the right earpad. Cool!
To make it work on the K3, I had to turn on the microphone bias (press ‘2’ when in the MIC menu
option to toggle bias on/off) and adjust the mic gain and compression to suit. The mic seems to
have plenty of gain: I have it set at just 6 on the low-gain setting (press ‘1’ in MIC to toggle
The PC 230 lead is comfortably long enough to stretch underneath the operating desk and plug into
the K3’s rear panel phone and mic connectors, reducing the front panel clutter and clearing my desk
a bit. I leave the front panel mic settings configured for the Heil headset that I prefer for contesting.
The Heil has closed earmuffs and a restricted bandwidth mic insert, although I could achieve the
same effect on a full-range mic using the K3’s TX equalizer settings, so perhaps it is time to retire
the old Heil.
My K3 wish-list & bugs
The K3’s firmware is amazing in what it can do but inevitably there are a few little bugs and flaws.
Here’s my current wish list:
There is a little firmware bug (acknowledged but unfixed by Elecraft) that stops CW-in-SSB
working if I power-cycle the K3 in SSB mode, with QRQ configured on, on any band except
6m (!!). Until the bug is fixed, power-cycling with QRQ configured off restores CW-in-SSB;
For some reason, CW-in-SSB also does not work if I assert the PTT line or operate split;
I used to use a footswitch to hold the PTT closed during a CW over, mostly to stop my old
valve amplifier dropping out between words. If I released the PTT footswith while sending CW
(relying on VOX to continue holding the PTT) or even if I turned on the PTT while the rig was
already sending on VOX, the K3 sometimes messed up the character being sent at that
instant. PTT handling should really be a lower priority than CW sending ... [The workaround for
this bug is to use QSK with a suitable amp such as the KPA500!];
Fast tuning is a pain: even with two speed control buttons (fine and rate) and using the
clarifier as a fast-tune knob, it is awkward to get between, say, the 10m beacon sub-band
and CW or SSB sections. “Ballistic tuning” was once mooted by Elecraft, meaning that the
tune rate will increase with the rate of spin of the VFO knob/s, and would be nice. Meanwhile I
am using the RIT/XIT encoder knob to move more quickly, and to set the VFO to round kHz
The V--> M button should be physically distinctive - I’ve coloured mine red with a marker pen
until I learn not to overwrite a memory when I meant to recall it;
There is no ‘quick memo’ function like on the TS850, FT1000 and others. I found that a really
useful way to store the current settings, whizz off to check something out, and return to
where I left off. On the TS850, a single button-press was all it took, or I could tune between 5
quick memo stores using a knob [I’m now using M2 as a single temporary memory. Not quite
as easy or flexible as a true quick memo function but better than nothing].
Other software defined radios are updated from time to time but users appear to have little say in
what changes are made by the manufacturers. Elecraft claims to be very responsive to customers
but I have to say that so far I have failed to persuade them to fix the three bugs in the top three
Elecraft W2 wattmeter
I bought the W2 mostly to address a simple problem: I sometimes forget to change antennas after
changing band and wanted a gizmo that would instantly lock out and so protect my old valve
amplifier if the SWR was too high. The W2 does that, and has LED bargraphs displaying forward and
reflected power. Fair enough.
It has a drawback, though, compared to big old Yaesu power meter I used to use. The Yaesu uses
a traditional analogue meter which gives better resolution (though probably worse accuracy) than
the W2. When tuning my old valve amp, the load and plate tuning is critical on some bands. The
analogue meter is better to squeeze out the last few percent of efficiency.
The kit was easy to assemble and works well, within the limitations of the LED bargraph anyway.
With hindsight, perhaps I should have invested in an LP-100A meter since its higher resolution LCD
display would be better for tuning the LK550 amp.
The connection between pickup head and display box uses an Ethernet cable. It would be interesting
to site the head remotely, at the far end of my long coax runs, in order to check how much power
is being lost in the cables and connectors ... but the supplied cable is only a couple of meters long. A
30m Ethernet cable evidently introduces too much resistance, but looking at the circuit diagram, I
see there are 1k resistors in most of the lines: I bet if I bridge them, it will work over the long cable.
<To be continued ...!>
Having lost the original W2 programming cable, I had to make one up ...
Elecraft KPA500 amplifier
The KPA500 is a 500W “key down for 10 minutes” FET amplifier running at 60V with a built-in
mains power supply. It uses fast electronic switching and hence gives
totally silent and lightning
- no relays to click and wear out. It is a no-tune design with low pass filters selected
automatically for each band (160 to 6m) using RF sensing or a connection from the transceiver -
more on that below.
As with the K3, building the kit involves assembling a set of panels and strengtheners for the case
and a few pre-constructed PCBs, the PA unit being the main one with its large heatsink. The kit
instructions said nothing about which way to mount the fan and it had no markings to show which
way it blows. In the end I put it with the label outside: it sucks air in through the top vents and
blows it out of the rear of the amp, which is the way I like it, voiding into the space behind the
shack desk rather than blowing in my face. It is nice and quiet, especially compared to the roar of 4
muffin fans inside my big old valve amp.
Aside from silent QSK, the size and weight of the KPA500 were big attractions for me as I plan to
use it for DXpeditioning. It is the same size as the K3 so it will fit into a flight case and can be taken
in the cabin of a plane as hand luggage. It weighs 12kg, about half of which is the toroidal
transformer. If needs be, the transformer can be removed without too much trouble and carried
separately in the hold.
QRQ QSK is a joy to use. Not only can I hear immediately when someone comes back to me, or
QRMs me, or comes back to someone else, I can also turn the beam when CQing on CW to find
the strong reflections that usually mean I’m getting out well in that direction. I can time my
transmissions to get around the oh-so-helpful frequency kops and other lids on my frequency, and
hear when my signal is going twice around the world!
K3/KPA500 data cable
I foolishly neglected to buy the Elecraft cable linking the K3 to the KPA500, thinking I could make
one up from connectors in my junk box ... but not only did I have none of the 15-way 3-row D-sub
VGA connectors, I couldn’t
even find a source to buy
them in NZ. Elecraft wanted a
ridiculous US$70 to ship me
the cable so instead I found a
local supplier of VGA
extension cables: cables
marked “VESA DCC
” have all 15 pins
connected straight through
with no gaps, no shorts and
no cross-links to the shield.
Sure enough, a VESA DCC
VGA extender cable from an
NZ supplier was correctly
wired and, at 0.5m tip-to-tip,
the perfect length provided
the K3 and KPA500 are
immediately adjacent on the
desk (I later splashed out on
a slightly longer cable). After
checking the pin numbering
(it’s embossed on the female
connector), I carefully pulled
out pins 1, 6, 7 and 8 from
the male end with a pair of
long nose pliers giving each
pin a slight twist to extract it whole rather than just break it off.
The converted VESA extender cable works well: the K3 and KPA500 are slaved to the same band.
Band changes can be made from either one. The K3’s output power can be set for two levels per
band, namely about 23W drive if the amp is operating or some other level (e.g. 5 or 100W) when
the amp is in standby. The K3 shows “KPA STANDBY” or “KPA OPERATE” and beeps once when the
amp changes status, just in case I didn’t notice the amp’s OPER/STBY LED change.
KPA500 firmware updates
Mostly the KPA just sits there quietly doing its thing, as any well-behaved amp ought to do. It talks
to the K3, follows me from band to band like an obedient puppy, ramps up its fan if it gets too
warm, backs off the power or alerts me to a fault if I do something silly (such as transmitting on
the wrong antenna). It delivers.
Elecraft occasionally updates the KPA’s firmware, far less often than the K3 since it is much less
complex. Having not updated my KPA in well over a year, I forgot how to do it, so here are my
notes as a reminder for next time:
Check Elecraft’s KPA software page for anything new (the KPA firmware and KPA Utility
programs were both updated since I last checked).
If the Utility was updated, download the new version and install it first. If you aren’t sure, run
the KPA utility on your PC and check the version number under
Help -> About KPA utility
Hunt for a serial/USB adapter that works. Plug it in to the PC. Check which port it has chosen
this time from Windows Device Manager (which is accessible using <Windows+Pause>) by
unplugging and re-plugging it to see what changes. [It may pick a different USB port if you
plug it in to a different USB port than when you last used it.]
Plug the serial/USB thingy into the KPA500’s upper serial connector, and turn the KPA on (if it
isn’t already on).
Run KPA Utility.
If KPA Utility doesn’t immediately give you a pop-up status message such as “KPA version 01
.23 RS-232 speed 38400 bit/s” (which means it is already talking to the KPA), select the
appropriate com port to kick it into talking to the KPA. You can also click
. Congratulations, your PC should now be talking to the KPA.
Open the Firmware
tab. The folder location should still be as you left it, if not find the
directory where you store your KPA stuff (in my case,
Copy firmware files from Elecraft
. This tells the utility to go to Elecraft’s FTP server to
download the latest KPA firmware to the directory noted in the previous step. Wait for it to do
its thing. It may give you a message about having found and downloaded something new.
If there was something new, click
Send firmware to KPA
to update the KPA’s firmware. The
KPA will click and put itself into MCUload mode, update its firmware, then click back to normal
about a minute later.
Play with the settings on the
tab if you like. You can remotely-control and monitor
the KPA with these if it is just out of reach, or somewhere across the planet.
Open the KPA configuration
tab. Put something useful in the power-on banner, such as your
callsign in case it gets stolen and recovered by the police (in the vain hope that someone will
work out how to operate the ON button, realise that your callsign is a unique ID, and turn up
at your door with the KPA in hand).
Save KPA configuration
to save its settings, just in case you ever need to re-load it
and can’t be bothered to reconfigure it by hand.
Close KPA Utility, unplug the USB-serial thingummy and hide it somewhere very secret to give
yourself something ‘fun’ to do next time.
Make yourself a nice cup of tea to celebrate and GET ON THE AIR.