The AM Forum

Building the Elecraft K3 - Here We Go Again!
When Nancy and I were visiting my folks back in New York state over the Christmas holidays, I had the opportunity to drop off a Henry amplifier to its new owner, Bill N2BC. Of course a hamshack tour was in order, and Bill has a very nice hamshack indeed, equipped with the latest and greatest in Elecraft gear, the K3. Bill's K3 really got me thinking...a Elecraft K3 would be a very fun project for the New Year...and I am always on the lookout for a new project...that it will do AM was just a bonus.

Over the past few years I've built a number of Elecraft kits for myself and for others, I'm on the Elecraft builders list, it is always a blast, makes the long Maine winters go quickly! The KX-1, K1, K2, and miscellaneous Elecraft mini kits, but never the K3, considered the top of the Elecraft mountain. One listen to Bill's K3 and I was hooked, needless to say, the order, with Bill's guidance and suggestions, went in shortly after I returned to Maine.

The K3 is different that other Elecraft offerings, it is a "no solder" kit, the builder basically assembles pre-tested and assembled modules...still, building is building and I was excited to get back on the bench. The kit arrived today, and I was in the barn this very evening, a cup of green tea at hand, sorting parts out into muffin trays, inventorying components, the old National HRO short wave set going in the background, a most wonderful Maine winter evening. Impressive number of modules and parts, each its its own Ziploc or static protection bag, had to move another work bench over to accommodate the space required by the pile of goodies. After the Ten-Tec 1320 build I just completed for another ham, I was glad to be working once again with Elecraft's excellent manuals, far and away the best of the bunch. Serial number 5068 is under way!

More at www.w1ujr.net, see the Bruce's Bench series, 2007-2011, on the left menu.


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Burce I met a Russian guy in Ca. last summer. He put a softrock in a K3 and computer controlled the whole thing. Sherwood rates the K3 highly.

I assembled my K3 a little over 2 years ago, and it worked flawlessly as soon as I fired it up.  Most of the time I use it on AM.  I set it for about 10-12 watts of carrier out and run that into an AL811H amplifier set for about 150 watts carrier out.  Since the K3 holds to whatever carrier power level you set it to, no ALC is needed.  Looking at the waveform on the scope, it looks like a pristine, A3 100% modulated trace.  On-air reports are typically "great sounding".  I use a high end commercial broadcast audio processor with it, and the K3 handles it well.  Plus, using the synchronous AM detector is a pleasure to listen to.  Good choice W1UJR.  Hope to work you on the air soon.

73
Ted  W8IXY

Hi Bruce,

Building the K3 is kinna fun ...  a LOTTA FASTENERS!

I built a pair (in the 600 SN range) a couple of years ago.  For whatever reason,  I never did warm to these rigs.  I had hoped to use one as an AM Exciter,  as it had a precise power control,  and it was an SDR.   But,  to me,  the transmit audio bandwidth being limited to +/-- 3 Khz,  make them have telephone audio.  It is punchy,  but not at all pleasant.  Even with the 13 Khz "FM" Filter,  the DSP is limited to about +/-- 3 Khz,  and IIRC one cannot select the FM filter for AM XMIT,  and still,  think that the DSP would still have hardware limitations.

Have been pleading with Wayne @ Elecraft to change this,  but as of now (to my knowledge)  to no avail.

Some of my other probs with the K3 in the past have been the difficulty in getting good SSB transmit audio.  Tha latest FW updates may have helped this some.  And I've gotten too used to using a 200 Watt XCVR -- the FT 1000D.  With a 200 Watt radio,  seldom have needed to turn on the Amp.

Not to rag too much on the Left-Coast Radio manufacturer.  Elecraft is a great company,  and they have provided good jobs for a number of local Hams.

YMMV      Vic

That K3 looks a hell of a lot like an HRO 50 I used to have.

Solderless Kit ??!!!    What kind of cheap pimp would sell a solderless kit?   ;D ;D

Just kidding. Have fun with the project, Bruce.  The K3 is one of the most sought-after rigs on the air.

T

Hey Bruce,

Just looked at your "2011 Bench" pictures...  Why did you photoshop all my hair away?

Happy New Year & enjoy the K3!

73, Bill   N2BC

Bill - I've aged since I last saw you...having employees does that to you!

JEK - The HRO is my back up option, EMF proof, provides the background atmosphere, usually on 75 AM or 40 shortwave.
Also serves to hold down my bench in the Maine blizzards...like today!

Vic - Not sure that is still the case, perhaps Bill N2BC can comment on that.
My understanding is that you can switch the various filters in and our for each band, and even use the W I D E AM filter on SSB - I see this on the Elecraft site "AM and (E)SSB modes have far more dynamic range and the 15 kHz IF image must be suppressed by some 10s of dB more than is required for excellent FM operation.  It is for this reason that the FM filter is recommended only for FM use.  It may also be used for AM receive, but is not allowed for AM transmit. The 6 kHz filter has the necessary 15 kHz IF image rejection to be suitable for use with either AM or ESSB transmit."

Ted - Thanks for the fine comments and encouragement! I have some very nice home-brew amps John W1FPZ left to me, 100th tubes, which I had thought of using, may just chicken out and use the Icom 4KL once I feel comfortable with the rig on QRP.


Those who asked, the K3 and options order is below.
Elecraft K3 Order
K3/10         K3 10W Xcvr. (Modular Kit)
KAT3               K3 ATU (Modular Kit)
KBPF3            K3 Gen. Cov. RX Module
KDVR3           K3 Dig. Voice Recorder
KFL3A-2.8_2.7   2.8 for 2.7 kHz swap
KFL3A-400      400 Hz, 8 pole filter
KFL3A-6K      6 kHz, 8 pole filter

Tonights progress below, final resistance and voltage testing and power up tomorrow!
More at http://www.w1ujr.net/bruce's_bench_2011.htm

Observations
- So far VERY impressed with the quality of the rig, assembled boards and layout very nice, lots of room inside!
- Speaking of room, nice modular design, you can remove panels for future upgrades and additions, some one was thinking here in design.
- Thought the felt washer behind the main turning knob - for drag don't 'ya know - a tad cheap, but otherwise spot on.
- Built many kits, don't mind taking a break from the soldering and lead clipping, so the "no solder" kit does not bother me as much as I thought.
- Elecraft's assembly manual is first rate, very nicely done, clear, hard to make a mistake.
- Definitely need muffin tins, or some other way to keep the hardware straight, lots of little parts.
- Don't know who is doing their sheet metal and powder coating work, but fit and finish as A1.
- "3D" block attachment points are nice, allow some adjustment of the sheet metal panels, but do require some tweaking to get just right.
- Would prefer some high tech, glow in the dark, laser engraved serial number to the press on sticker, but just being picky there.
- Only real wish, why not USB port interface, still serial, haven't owned a serial port computer in nearly 10 years.

Photographs - Nikon D90
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Fine looking rig! I've wanted one since they came out... But then there is the small matter of convincing the war department... ;D

So I had another drool look at the Elecraft site today and noticed a feature I hadn't noticed before... You can use CW to send RTTY or PSK. And it'll decode it on the display.  :o :o :o

THAT is something I'd love to try!

Have fun!

Hi Tim,

Did not know about the decode feature, very cool!
I'm having a ball building it, its like an errector set for adults, all bolt togerther - no solder.
I've got a K2 to build for another fellow, suspect that is going to be a downer after breezing through this.
Best part - NO TOROIDS TO WIND - I am way over that, was fun for the first two, maybe three..

Hope to power it up this evening...

Yup. I have built the K2 and KX1, both with almost all of the options... Toroids are a BIG drag! The soldering was fun though, and there was a big sense of accomplishment during the builds of these rigs.

I imagine that if I ever get a K3, I'll get the kit. And it will still be a fun project. If anything, it will make future upgrades much easier.

The CW to PSK and RTTY is a great idea. I personally don't have much interest in these modes simply because I'd have to bother with a computer for send/receive. Having it built into the rig allows the modes to be used anywhere - no computer, no keyboard, just a paddle - which I carry anyway. Yet another example of the thought that goes into the design of these rigs.

Check this CW-RTTY video out:

http://www.youtube.com/watch?v=-0o9N3hH9oQ

Cool video, I did not know the K3 did that, wow!
Hope get mine on the air over the weekend.

Have you see this video, 7 Minute Elecraft K3 Build?
http://www.youtube.com/watch?v=DfUMZcwtIyw

Hi Bruce,

Thanks for the info on AM BW ... 
I did print to the LCD display some RTTY with it.  It is cute.  And as you know you can send RTTY using the paddles.  Giving rise to the comment, "RTTY with a K3 Fist",   as the spacing twix the RTTY characters is variable depending upon the weight count of the character in CW.

Was fun to build.  Was very impressed with the metal work's accuracy,  but it is prob all CNC,  or some of it is prob hard-tooled by now.

72  Have Fun,   Vic

The K3/10 build is done - complete story, please excuse the spelling and grammar errors, at http://www.w1ujr.net/bruce's_bench_2011.htm, some details below:

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First Contact - Antique Wireless Association AM Net
My first QSO with the new rig was today on the Antique Wireless Association Sunday AM PM Net on 3837, altogether fitting that the rig should make its maiden voyage both on AM and on the AWA Net! A most interesting juxtaposition, 1940s antique gear meets the latest and greatest of the 21st century! Thanks to Bill K1BF and Dave KA2J for listening very hard for my little 2.5 watt QRP signal.

K3 Utility Software - KSUB Adaptor - A Small Glitch
First, kudos to Elecraft for supplying software for the Mac, so little ham software is written for the Apple side of things that it was a pleasant surprise to see that both a PC and Mac version of the K3 Utility software was offered on the Elecraft website. The K3 Utility software is used to set up and test various rig parameters, and while not required, is very handy to have. With that said, I did have a bit of a challenge with the K3 Utility software. Like most new computers, my Apple Macbook Air does not have a serial post, just two USB ports. The K3 uses a serial port, necessitating the use of the Elecraft USB to 9 Pin Serial cable, known as a KUSB. I could not get the K3 software to find the cable on the Macbook. I tried various software drivers, searched the internet and Elecraft email archives with no success.

A quick post to the Elecraft reflector, and within 10 minutes of my post Bill K1GQ nailed it, the drivers from the Elecraft site are NOT correct for the FTDI chip set used on the newer KUSB cable. I downloaded the correct driver from the site Bill suggested, and things just worked! Just 100% delighted how quickly and well the K3 Utility works. The site for the FTDI chip is located at http://www.ftdichip.com/Drivers/VCP.htm Even more delighted with the prompt and accurate help provided by K1GQ on the problem, hope this saves someone else from this problem. So, if you've having an issue with the KUSB on the Mac, perhaps even the PC - I can only speak with the Mac, use the Mac System Profiler to determine which chipset your USB to Serial Adaptor is using, then make sure you download the right driver.

Crystal Filters - Double Check/Double Take
I found the otherwise excellent Elecraft assembly manual a tad confusing, at least to me, on the arrangement of the xtal filters. I had chosen the 8 pole xtal Inrad filters for the K3, the layout is as follows: 250 KC, 450 KC, 2.8 KC, 6.0 KC. Those with a sharp eye will note that I initially had the filters installed in the incorrect order in K3 because I misunderstood the manual. A reading of the operations manual made things much clearer to me, and I quickly reinstalled all of the filters from the widest bandwidth to the most narrow. The new order is: Filter 1 is blank for future installation of the FM filter, then I set it up the following filters from widest to most narrow, 6 KC in slot 2 for AM, then the 2.8 KC filter for general use, followed by the 450 and 250 KC filters for CW use in slots 4 and 5 respectively.

Using A Icom Microphone on the K3 - General Info
I have a number of Icom rigs here, and more than a few spare mics laying about. I decided to use a Icom SM-8 with the K3. The SM-8 has a bit of retro look about it, nice contrast to the K3, and the electret condenser type mic element gives clear tone over a wide variety of voice levels. On the bottom of the mic base there is one control for tone. Designed to be used on two different rigs, there are separate level adjustments for input A and input B. The mic cables terminate to a standard ICOM 8 pin mic plug.

The use of a Icom mic requires a few simple changes as Elecraft has wired the microphone jack on the K3 to match the Kenwood wiring scheme. Unlike the K2, the user can not readily change this scheme, so the changes have to occur inside the microphone or cable plug. The pin out information on both the Icom and Elecraft is below, again, hope this helps someone else. You have two settings on the K3 which need to be enabled to use with the Icom microphone, the Bias voltage, and the Mic Gain. For my station I used the high mic gain setting, and also used the bias voltage, seems to work just fine. The Icom memory channel or freq changing is implemented differently that Kenwood, Icom does this by pulling down a control voltage with a 470 ohm resistor. Adding the functionality of the UP and Down buttons will require some additional work, I have not implemented that, but may do so at a later date.

Final Thoughts
I'm had a ball building the K3, its like an erector set for adults, all bolt together - no solder. I've got a K2 to build for another fellow, suspect that is going to be a little more of a drudge after breezing through this. Part of what makes the experience special is the support of the Elecraft community, like the AM Fone site, there are dozens upon dozens of knowledgable folks more than willing to help out with anything question or glitch you may encounter, that sense of community is invaluable. Best part - NO TOROIDS TO WIND - I am way over that, was fun for the first two, maybe three kits, but no more. I did not add the 100 watt module, happy to run with the QRP 10/12 watt LPA, that seems to be the focus for me in 2011, less is more.
 

Congrats Bruce! Must have been great to get that baby powered up and on the air. I remember similar moments when making the first contacts with the KX1 and K2. Elecraft kits are addictive!

This thread is adding fuel to the fire here. Even though I am having a ball with AM and hollow-state electronics in general, I have a soft spot for all things Elecraft. I have to find a way to convince the war department I need a K3.... ;D

Enjoy the new rig!

Congrats on the K3 build Bruce!   8)   Back in November, when I received a VERY NICE profit sharing bonus, I was seriously tempted to get the QRP kit version of the  K3 (which it sounds like you have).  I think the only reasons I didn't were because of its price ($1500), which would have stressed out my finances (even with my bonus), and the fact that I found a Kenwood TS-2000X, at a great price, and coupled with the fact that it not only does HF, but does 6, 2, 432, and 1296 with decent performance, I just couldn't resist it, being a longtime VHF and UHF weak signal op.

73 & have fun with the K3,
Ellen - AF9J

Tim - Since you have built the KX1 and K2 kits you'll love the K3, the biggest problem is how little time it takes! Where as I could make either of the early kits last at least 7-10 evenings, the K3 is easy to breeze through...a bit like enjoying desert instead of dinner. By all means get the K3, I sold other gear to justify...new rule in the shack, Bruce's Radio Law #2 - Whatever comes into the shack has to be smaller and weigh less than what went out the door. :-) Should you find funds allocated in the next war dept. budget, by all means let me know, would be fun to enjoy an K3 to K3 contact.

Allen - lots of the K3s used, pretty reasonable too, think some folks enjoy the thrill of building more they do operating...

I love mine. I have a 100 watt module and the 2 meter module that I need to install. Love the receiver.

Robert- I've seen the 2 meter module option, would love to hear your feedback that on installed. I've not been on 2 meters from house, would be interesting to "listen in".
Installing the aux ant and I/O board over the weekend.

Half the fun is the K3 community, some real creative folks there!

Well, I've caved in... I'm going to throw my hat in the ring and get a K3 together. ;D

As a belated gift, the YL is getting me the tuna, PA, I/O, and a couple of filters. The tuna and I/O are in the mail! ;D That means I have to break open my piggy bank to get the K3/10. But, now I'm committed.  :D

This all works out good, as the base price of the rig is not that bad. It's the options that are a killer. And there are LOTS of options... That P3 looks amazing. ;D

Bruce, I'm debating on the 8-pole filters... is it worth the upgrade to do the 2.8 > 2.7 upgrade? I'm planning on the 6kc and 400kc filters.

Very nice Bruce.  8)
You're getting a lot of comments from what's generally known as an ol'buzzardly, tube oriented set of gangstas. 

So the K3's obviously generated much interest.

What power supply are you using?  Can your supply be remotely turned on through the K3? Guess I should download the manual.   I did see the K3 uses Anderson connectors.

I see you've also listed yourself as a 'builder' to help others on the K3 site.
Very commendable.

Thanks for a great write up and 'review.'

Tim - Oh boy you're in for some fun, congrats on the K3, and you picked a fine business YL to get the goidies for you, fine business indeed! I wish I could give you a good answer on the 5 vs 8 pole filters. Check with Bill N2BC on that one, I did order the 8 pole, they were not that much more, and the 2.7/2.8 upgrade, figured I only wanted to buy them once. I've got the 250 c, 400 c, 2.8 kc, 6 kc filters installed, with the 13 kc coming tomorrow. P3 looks vey cool, lots of chatter on the P3 on the Elecraft email reflector, worth signing up...word of advice, get the digest form, lots of daily traffic. Let's set up a sked some time when your are done with the K3 build.


Rick - Yes, lots of buzzardly folks, most of us are getting too old to lift anything but a K3...kidding, I'm 46, but do think folks like new technology, even if it's solid state. I've
always noted two distinct classes in the amateur service, who I call the 1) Communicators and the 2) Builders.

The first class just sees ham radio as a cheap way to chat with friends, and doesn't care one bit how they do it, my friend Tom calls these folks the "Shack On The Belt", radio is a means to an end.

Class 2, which most of us on this board tend to fall into, is more intereste in the means than the end. We were the ones who pulled apart our parents radios growing up, or took the cover off the back of the TV to see what was inside. We were the kids with smoke, sparks and smells emanating from our bedroom or basement workshops...so the K3 is but another gadget to be poked or prodded. :-)

Nice thing about Elecraft is that you can download and read the manuals before you buy.
Manuals Here - http://www.elecraft.com/K2_Manual_Download_Page.htm
K3 FAQ - http://www.elecraft.com/K3/K3FAQ.htm

PS right now is my bench supply, nothing special old buzzard, non-switching type. The K3 can be remotely turned on via the accessory conector, not sure if and extra set of contacts for remote switching the supply...think that was your question.

Elecraft builders list, yes, it's been fun, have built a number of K1, K2 and KX1 kits for folks, free for elderly or handicapped hams, low fee for others. Some of my build traffic
tapered off when I stopped winding toriods for the kits, and ask folks to order the pre-wound ones. Little else knocks the wind out of you more than discovering your eyes have aged to the point where you have a hard time counting turns of #26 magnet wire without a magnifying glass :-(

Welcome on the review, thanks for reading my ramblings.

-Bruce

I'd be willing to bet HPSDR type hardware lands in a K4 or K5
now that would be very cool, just add a monitor for wide screen

You might be right Frank, was hoping Wayne and the boys might finally release an RF amplifier.

http://www.n6ie.com/Elecraft.html

or

http://picasaweb.google.com/drnesbitt/ElecraftKPA500AtDayton2010#5471965491966740146


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It may be sooner than you think... The K3 pretty much IS an SDR, and new features are being added with every firmware release. I saw recently that they added an AM synch detector, just for us AMers! (and swls...)

My thing is, I just can't get my arms around a completely software-defined box that relies on a computer to function. Perhaps if I were a hardcore corn-tester that spent all of my operating time in front of a computer, I'd feel different, but... I'm not.

Also, if you look at the back panel of the P3 Panadapter, there are labeled cutouts for a keyboard and external display, as well as some other stuff. Future goodness abounds. Perhaps a nice K3 dream-station would be a flat-panel display on the wall as your band scope, all run from that tiny rig.  :P

Bruce, we'll definitely set up a sched when I get things all ordered and put together. If you could, when you get an opportunity, I'd like to hear your impressions on the 250hz and 400hz 8-pole filters. I'm thinking that the 400 should be good as a general purpose CW filter, and you of course can narrow things down further with DSP, but I'd like to hear how the 200hz works in nasty, crowded conditions. And of course, is 200 too narrow for anything but those nasty conditions? I have no trouble with the K2 filters on CW, even the narrowest one, which is 200hz. I find the K2 on the 200hz filter very comfortable to use, just not too practical to tune around with...  :P

FWIW, I've got a bunch of K3 related info at http://n1eu.com (http://n1eu.com)

When I first got my K3, I got both the 2.7 and 2.8 filters.  I would say there's a very slight advantage to the 2.8Khz filters - slight wider/flatter passband but almost unnoticeable and questionable upgrade.  That being said, I do use the 2.8 filters and shelved the 2.7 filters.  But my ssb ragchewing receive and transmit uses the 6Khz filter anyway.

For cw, I have 500 and 200 5-pole filters and very happy with them - the 200hz filter is configured as 300hz and is my full time cw filter - sails through the toughest condx.  I'm thinking of pulling the 500hz filter.

I am disappointed in the narrow AM transmit passband (about 2.8Khz).  The ESSB transmit sounds much better than the AM transmit.  Perhaps a bunch of us can petition Elecraft to open up AM transmit passband to 4Khz (through 13Khz filter) like they did with ssb (through 6Khz filter).

I highly recommend the subrx - stereo diversity is addicting and a big help on the low bands using multiple receive antennas.

73, Barry N1EU

Tim - Hope to get some K3 time in this weekend. We've got a big snowstorm coming in today, which normally means radio time, but have a seminar in Boston and will be gone most of Sunday - my Retro 75 just arrived, so go figure, perfect radio week, with a revenue generating/work thing stuck smack in the middle of it!

I think you've got the general idea on the 400 filter and narrowing down, again the Elecraft reflector or N2BC have much more face time than I. I will say that on my other rigs, for copying CW, I really do like the most narrow filter I can get, removes all of those side distractions..suppose if I was a really skilled CW op it would not matter...

Barry - Thanks for the info and link, looks like good weekend reading, I've got a lot to learn about this rig.
Correct me if I am wrong, but I thought that I could assign which filter is used on TX, I see that setting in the K3 utility, and assigned the 6KC filter to AM. How much of a project was the sub-band RX to install, looks like a bit of chore, and I wonder how much I'll use for casual rag chewing..not operating split..but I do like the simulated AFX feature, that's too cool!

-Bruce

TX filter assignment isn't really optional.  AM tx uses only 6Khz filter, ESSB tx uses only 6Khz filter, SSB tx uses only 2.7/2.8 filter, CW tx uses only 2.7/2.8 filter

The subrx install is quite straight forward and pretty quick project.  I use it all the time for casual rag chewing.  I'll typically listen in stereo with my tx antenna feeding the main rx thru R channel  and a Beverage feeding the sub rx thru L channel - works great 160M-20M.  Using stereo heapdhones, have a listen to:

http://n1eu.com/K3/75M_AM_9Nov08.wav (http://n1eu.com/K3/75M_AM_9Nov08.wav)
(vertical ant feedling left channel, Beverage feeding R channel, 6Khz BW, AGC off)

73, Barry N1EU

Update: I just heard that the K3 firmware may eventually be updated to provide wider tx audio passband (4KHz?) by allowing AM transmit through the 13Khz filter.  I believe this would make the K3 the only serious AM platform (i.e., >3KHz rx/tx audio, sync-AM) among modern off-the-shelf rigs, besides the Flex.

Barry