Elecraft K3

January 10th, 2009 by g0vgs

Building the Elecraft K3 is a joy.  The engineering design that has gone into the radio is amazing.  The tolerances of the case fittings are fantastic.  I have actually built three of these so far (only one for me unfortunately) and they were all straightforward to do.

I have had mine for just about a year and it has not disappointed me yet!  I don't expect it to either.

What follows is a quick look at how to build a K3 from opening the box to operating.  I hope you find it useful.

The Elecraft K3

The Elecraft K3

When the K3 arrives it comes in one large box.  The first thought on opening the box is how many other boxes are inside it!  They are extremely well packed too.

A box of Boxes :)

The first thing you should do is find the manual and the errata and annotate your manual.  Once that is done, inventorying the parts is useful.  A thought at this point.  It is very easy to end up with stuff everywhere.  There are so many packets and boxes that it is easy to lose things, so try and work in a logical manner.

The other thing to do is to ensure you have an antistatic mat and wristband.  There are many static sensitive components on the K3 boards and the last thing you want to do is to create a problem that might not show up immediately but arrive later when you have no idea what caused it :)   If you are spending this amount of money on a radio, it is worth an extra few pounds to buy an anti-static mat and accessories.  Every workbench should have an anti-static area in this day and age.

Once you are ready to start, find the RF board.  This is the basis of the whole construction of the kit.  Everything starts here.  What you do first is attach six 2D connectors to the edges of the board.


This is looking from the back of the board.  You can just see the one of the 2D connectors at the bottom right, fixed by 2 small black screws.  Never over-tighten the screws, just use enough force to stop the 2D connectors from moving.  Ensure they are aligned with the edges of the board.

Next the filters are fitted.  You should put these in order of width if only for ease.

RF board with filters fitted

This shot is from the front of the board and you can see it has the 6kHz AM and the 2.8kHz roofing filters fitted.  There is a space left at the first filter slot in case the 13kHz FM filter will be fitted later.  Up to 5 roofing filters can be fitted.

K3 RF board with shield fitted

The next stage is to fit the front panel shield.  Amongst other things this serves to protect the front panel from any stray RF.You can also see in the photograph that the low power PA has been fitted.  It simply pushes on to a couple of headers with very little force.  This small PA board is capable of 12W.  This will eventually be screwed onto the bottom cover which also acts as a heatsink.

Once this is done, the left hand side is fitted (the one with the handle) and in this case the ATU as well.  The rear panel is  fitted and the RF connectors.

Coming together

You can clearly see the radio coming together now.  It will look more and more like a 'proper radio from this point :)

The next step is to fit the IO boards at the back of the RF board.

IO boards

Again in this picture you can see the low power PA board.  The IO boards mount on to the main vertical board you can see here and protrude through the rear panel.

IO connections

You can see, from top to bottom and left to right, the RS232 computer connection, the Accessory connector (NOT a video connector!) then extn speaker(s), headphones, microphone, line in and line out.  Below this is the transverter board which has receive antenna pass through and IF out connectors.  Finally paddle, straight key, PTT, key out and a blank plate.

Next locate the parts needed to prepare the front panel.  This is basically the board, DSP board and hardware.

Front panel board

Once fitted together it will look like the image below.

Completed front panel

You can see that although it is not fitted to the radio, it is complete in every way.  This is now fitted to the main RF board by sliding it carefully onto the connectors.  This part of the process is possibly the most awkward.  It is worth taking your time and being careful, although some small force may be needed to seat everything correctly.  Don't worry if the top seems to lean away from the case slightly, it is held in place nicely by the panel screws.

Adding the sythesizer and mixer boards

The photograph above shows the front panel in place and the sythesizer and TXCO boards in place on the rear of the front panel shield.  Top right you can see the tiny mixer board too.  Also in place now is the strengthening bar (left to right in the centre) and the PA shield.

General coverage board

From above you can see the small mixer board on the right.  To the left of that and slightly above you can see the noise blanker board and in the centre of the shot you should be able to make out the general coverage receive board.  This is really quite clever.  Within the amateur bands, band pass filters keep unwanted signals out, improving the radio's performance.  If you add this option, when you tune out of band, the general coverage board is switched in, allowing you to tune just about anywhere within the radio's receive capability.


So here is the radio complete.  Above from the front and below from the back.


Note the fans.  The PA is fitted into this K3 and the fans come as part of that package.  If you have not got the PA, you will have a blanking plate covering the hole.  The fans are quiet as a mouse, even running at full speed!

So that is it!  A completed radio.  You can see the radio below next to my K2 which will be the subject of another post!

K3 and K2

Posted in Elecraft, K3, g0vgs | 1 Comment »

One Response

  1. Brian Says:

    Hello Folks,

    I have just had the opportunity to look at the projects part of the new website and I have to say it looks great.

    The background color is pleasing to the eye.

    The font is small but perfectly readable.

    Photographs are well sized, and sharp.

    The information is presented in small parts relevant to the photographs and presented in a clear and easy to understand manner.

    Mikes video was nicely put together and he did a great job explaining what he was doing and the end result he was aiming for.

    Well done all round.

    Brian G0RDH

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