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Elecraft Builds

And now dear readers, another episode of that fascinating radio serial…
Bruce’s Elecraft Builds
A randomly updated view of some of the various Elecraft kits which I have built.
Burdened with but a smattering of commentary, this is more of a visual tour. 
For more of my handiwork, be sure to check the “Bruce’s Bench” series,
you’ll find a link to those on the left menu on the home page.

Click on each photo to enlarge.

April 18, 2011 – Elecraft P3 Panadaptor Build #1254
A fun build taking just over 1 hour, the P3 is a stand-alone DSP spectral/waterfall display unit that’s a perfect match for the K3. It has a built-in, high-contrast color display (LCD), point and click QSY tuning and better plug and play integration with the K3 than is possible with PC-based panadapters. P3 features include 2 to 200 kHz of span, signal averaging, peak hold, adjustable gain and adjustable reference level. It also includes a buffered IF pass-through for support of additional IF processing.


April 17, 2011 – Elecraft Active Audio Filter Build
The Elecraft AF1 is a versatile audio filter that can be used with any receiver or transceiver. It can improve intelligibility of CW, phone, or data signals, and is especially well suited to radios that have inadequate I.F. or audio filtering. A rotary switch on the unit allows you to select a low-pass characteristic with adjustable upper frequency roll-off, or a narrow bandpass characteristic. The bandpass filter offers two levels of selectivity, and its center frequency may be tuned from about 350 Hz to about 950 Hz. The low-pass filter is active during bandpass operation, allowing you to further control the upper frequency response. The output amplifier drives low impedance phones or a small loudspeaker. Power can be supplied via either an on-board 9-V battery or an external supply. An LED indicates power on/off status.

April 15, 2011 – Elecraft BL2 HF Balun Build
Highly-efficient balun can handle up to 250 watts and can handle 1:1 and 4:1 ratios via an on board switch. It is very small (just 1.5 x 3″) and lightweight, making it an excellent choice for both home and field use. It uses a special winding technique to reduce losses and extend the useful range, resulting in an SWR of less than 1.2:1 from 500 kHz to 55 MHz (200-ohm load). It includes rugged screw terminals for the balanced output as well as ground, and can be used in a variety of matching applications.

April 15, 2011 – Elecraft KX-1 Transceiver Build
Stage 1  complete.

April 10, 2011 – Starting Another Elecraft KX-1 Transceiver Kit
Starting yet another KX-1 kit for a brother ham, always enjoy building these little rigs, the KX-1 packs an amazing amount of performance in a little package. Waiting for the pre-wound torrid coils to arrive, I’ve wound my share and now appreciate the pre-wound type, would rather save my eyes for reading!

April 9, 2011 – Building and Installing The Retro Helper For The Retro 75
Another homerun from Small Wonder Labs, the “Retro Helper” allows the Retro 75 transceiver to use the receive VFO as the transmitting VFO. No longer are you “rock bound” on two xtals, you can tune and transmit on the same range as receive. My rig covers 3835 to 3886 MHz, allowing some fairly good operating real estate.

The kit build is very straightforward, and if you’ve already built the Retro 75, you’ll find the Retro Helper a real breeze, took me about 2 hours, and that was being extra fussy about lead dress, solder connection quality, etc. The Helper board installs on the rear panel of the Retro 75 enclosure, using predrilled holes, and requires just 4 leads for connection to the Retro 75 main board. You can find the Retro 75 and the Retro Helper at the Small Wonder Labs website

April 9, 2011 – Collins 75A-1 Alignment and Service Inspection
It had been some time since the old girl has been on the bench, dating back to my 2006 restoration.
Thought I’d take another crack at aligning the IF as I was not certain it was spot on. The original crystal in
the crystal filter was slightly off it’s target frequency of 500 Kc, so a quick align of the fixed and variable IF
brought all back into spec. The trusty HP 8640 signal generator was the ideal tool here, and I found I was
able to peak up the IF just a tad. The rest of the alignment was spot on from 5 years ago, a testimony
to the solid design and construction of the Collins gear.

April 10, 2011 – Elecraft K Line Station
With the K3 built, I made the plunge and am going to a “K Line” station. A most clever name play on the old Collins “S Line” nomenclature. The K Line is a most worthy successor, and somehow I think that Art would be pleasured. So have the P1 and KPA500 kits coming in, really looking forward to this.

March 19, 2011 – Elecraft K2 – Adding 60 Meters and RS-232 Control Board – KIO2 and K60XV Modules
Full computer control of the K2 is possible with the KIO2 installed, the KIO2 provides true RS-232 levels.
The system is compatible with most contesting and logging software, including some Mac based programs.
The KIO2 Programmer’s Reference provides extensive information for those writing custom K2 control programs.

Inside a fully optioned out Elecraft K2 – You can see the KIO2 installed, note the cable and two circuit board on the front and rear panels, the large gray colored wire is the data connection. Removing the right side of the K2 make it much easier to install the connectors for the RF, Power, Speaker and Data. Inside the Elecraft K2 transceiver, most modules are removed for service access.
Bottom view of the K2, with the front bottom cover removed for installation of the K60XV coaxial cable. Bottom view of the K2, with the front bottom cover removed for installation of the K60XV coaxial cable.
Front KI02 Board during build. Front KI02 Board during build, fully populated.


March 12, 2011 – Elecraft K3 – Adding The K144XV Internal 2 Meter Module
With the Elecraft K144XV internal 2 meter module installed, the K3 makes another leap forward in versatility.
The K144XV covers the full 144-148 MHz U.S. allocation, sp weak-signal CW/SSB work is possible, as well as
access 2-m repeaters. The receiver has excellent sensitivity and dynamic range. The maximum transmit power
output is 8-10 W in all modes, with diode switching for silent, relay-free T/R. Best of all, it fits right inside
the K3!

February 22, 2011 – Scope Testing Modulation On the Retro 75 Transceiver Using Elecraft Mini Modules
I’m not measuring a Elecraft transceiver here, but rather demonstrating the use of the Elecraft Mini Module kits
on the Small Wonder Labs Retro 75 AM Transceiver. Interestingly enough I found that modulation was only possible
to 60-70% before distortion occurs.

Measuring set up used – Retro 75 transceiver built by W1UJR, Elecraft DL1 Wideband Dummy Load,
Elecraft CP1 Directional Coupler, Elecraft 2T-gen 2-Tone Test Oscillator, and Elecraft W1
140W Computing Wattmeter and SWR Bridge for initial set up. All test equipment built
by W1UJR from Elecraft kits.

Found power output about 2.5 watts with an unmodulated carrier, does rises to about 4 watts at 60-70% modulation.
Waveforms were recorded on Tektronix THS720A Digital Oscilloscope.

AM Modulation Measured on W1UJR Retro 75 Transceiver Ideal measured waveform – 100% modulation


Elecraft DL1 Dummy Load Elecraft CP1 Directional Coupler
Elecraft 2T-gen 2-Tone Test Oscillator Elecraft W1 SWR and Power Meter
Close in view of the Retro 75 board, coils wound and board build by W1UJR Overview of the transceiver, sitting on top of build manual for size reference.


January 29, 2011 – Building The Elecraft N-Gen Wideband Noise Generator Kit
Why does one need a device which generates a wideband noise on the HF bands? Well, its not as malicious as you might think, in fact its really quite useful for aligning filters, doing a quick check of receiver operation, etc. I found this a simple but fun kit, takes less than an hour to build, and perfect addition to the test workbench, which also includes the Elecraft W1 140W Computing Wattmeter and SWR Bridge, the XG2 Three Band Receiver Test Oscillator / S-Meter Calibrator, and now the XG2 Three Band Receiver Test Oscillator / S-Meter Calibrator.

The folks at Elecraft tell it best, so here is the description of the unit from their website:

The Elecraft N-gen is a wideband noise source that is useful for a variety of receiver alignment tasks. It can be used in conjunction with a software program such as Spectrogram to align IF filters in the K2 or in other receivers. It can also be used to align the RF stages in Elecraft XV Transverters or other HF, VHF, and UHF equipment. Note: The N-gen does not generate repetitive pulse noise, so it cannot be used to test pulse-type I.F. noise blankers such as the Elecraft KNB1 or KNB2.

Power Requirement: 9V battery or external 12 to 15 volts DC
Current Consumption: approximately 25 ma.
Excess noise output: approximately 35 dB
Bandwidth: within 3 dB from 100 kHz to 500 MHz

N-Gen Noise Generator Kit Assembled N-Gen undergoing testing
Using the N-Gen to check a transceiver, connected to antenna input, signal is displayed on S meter Note the S meter reading from the N-Gen, perfect for testing filter alignment, etc.


January 23, 2011 – Elecraft K3 – Adding The KPA3 Internal 100 W Upgrade for K3/10
The 100 Watt PA module simply converts the QRP version into a standard QRO HF radio, QRP is still possible when the power level is reduced, thus making the K3 able to do double-duty as a QRP/QRO radio. In fact, the front panel display automatically switches between the 1-10 watt and the 1-100 watt scales when the K3 switches from the low power IPA to the higher power unit, nice feature Elecraft!

January 23, 2011 – Elecraft K3 – Adding The13 Kilocycle Filter
Great for listening to HiFi AM amateur and short wave broadcast stations, really opens things up from the stock 6 Kc filter!

January 23, 2011 – Elecraft K3 – Adding The K3XVA Board

January 16, 2011 – Elecraft K3 – 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.

2011 Elecraft K3 1947 Collins 30K


January 16, 2011 – Elecraft K3 Build Finished – Works Wonderfully!
Finished the K3 today, spent a good part of the day doing the final tweaking, listening to 75 meter AM group as I type this. All told it took me 5, maybe 6 days, I spent mostly a few hours each evening, choosing to take my time to assemble, test and verify the kit. Sure that I could have done it one or two sittings, but I choose to savor the experience, it really was fun, of course one fellow did it in 7 minutes… Of course that’s a time lapse video, done over several days, but still one gets the idea.

General Impressions
I 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 knowledgeable 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.


January 16, 2011 – Elecraft K3 – Final Building Tips and SuggestionsK3 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 on the Elecraft website. The K3 Utility is used to set up and test various rig parameters on the K3 transceiver, and while not required, is very handy to use. With that said, I did have a bit of a challenge with the 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 a USB to 9 Pin Serial cable, Elecraft sells such a cable, known as a KUSB. Despite repeated efforts, I could not get the K3 software to find the adaptor cable on the Macbook. I tried various software drivers, searched the internet and Elecraft email archives with no success.

Finally, I made a quick post to the Elecraft reflector, and within 10 minutes of my post Bill K1GQ nailed it. Turns out that the drivers from the Elecraft site are NOT correct for the FTDI chip set which is 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 Even more delighted with the prompt and accurate help provided by K1GQ on the problem, hope this saves someone else from this challenge. So, if you’ve having an issue with the KUSB on 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.

How To Wire The Icom SM-8 Microphone To The K3
To implement the simple microphone cable mod, use the table below.
For simplicity sake here is a simple list of how I switched the cable leads:

1) Remove the two screws on the female mic cable clamp, then remove the one small screw holding the mic
connector into the shell.

2) Now twist and remove the mic connector from the shell, slide back the clear plastic sleeve to access the small pins on the back of the connector.

3) Using a fine tipped soldering iron, carefully unsolder Pins 2, 5 and 6 on the Icom mic plug, be sure to note which color wire went to each pin, see chart below if in question – note, your cable colors may not match mine, so best to make notes.

4) Solder the wire removed from Pin 2 to Pin 6 (bias voltage).

5) Solder the wire removed from 5 to Pin 2 (PTT)

6) Solder the wire removed from Pin 6 to Pin 7 (ground to ground).

7) For the VFO or memory channel up functions, skip this step now, I’ll have more data in a future post.

8) Reassemble the mic connector back into the shell.

9) Using the K3 Config menu set up the Mic Gain and turn on the Bias voltage, see the K3 manual for info.

10) Set the mic gain pot to a setting which sounds good in your on-air test and you should be all set.

Icom Pin Connection Wire
1 Mic Input White 1 Mic Input
2 + 8 VDC Black 2 PTT
3 Up/Down Blue 3 Down
4 Squelch N/C 4 Up
5 PTT Red 5 Function
6 Ground Brown 6 Bias
7 Mic Ground Shield 7 Ground
8 Audio Out N/C 8 Ground


January 12, 2011 – Elecraft K3 Build Day 2
Ready for resistance checks and power up tomorrow evening!

Basic Configuration
I kept my kit pretty simple, the options order is below.

– 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-250 250 Hz, 8 pole filter
– KFL3A-400 400 Hz, 8 pole filter
– KFL3A-6K 6 kHz, 8 pole filter


January 11, 2011 – 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 amp to its new owner, Bill N2BC, his photo below. Of course a shack 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…

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. Serial number 5068 is under way!

The Elecraft K3 – Stock Photos

Blame it on Bill N2BC – A Very FB OM

Starting My Build – Had To Add Another Workbench To The Line Up!

July 25, 2009 – Building the Elecraft K2 CW Audio Filter
Elecraft has the best kits, what a great way to spend an evening!

March/April 2007 – Elecraft K2 Build

March 2007 – Elecraft K1 Build

February 2007 – Elecraft KX1 Build