Rugby Amateur Transmitting Society


Elecraft K3 by G7BQM

Xmas 2014

For those who have followed the Elecraft story and are looking for a top-end transceiver, please read on.

Having built a K2 kit, once the initial surge of improvements had settled down, I enjoyed carrying out some of the later modifications and using the rig.  Some are simple, merely involving the change of a leaded component or two and are beautifully documented by Elecraft (in Heathkit style).  Others are user developed, most of which are also very professionally explained.

I have read about the K3 on the Elecraft reflector since its early design stages some 8 years ago now.  This radio has one of the best receivers in the amateur radio market and a very clean transmitter.  It weighs about 8lbs and has largely replaced the IC756ProIII on dxpeditions.  Two K3s can operate on the same band in close proximity, driving linears without problems.  The announcement of a new synthesizer board last month, has further reduced IMD and improved both receiver and transmitter performance.  Although all K3s were not created equal, all serial numbers from the earliest can be brought up to the latest specification rather than needing replacement with the latest model.

After several years of convincing myself I didn’t need one, mostly because of the cost and complexity, I finally succumbed and bought a used one from a UK amateur near Newcastle.  Terrible when you have to buy your own Christmas presents!

K3 Ser No 104 was a bolt together 100W version which had never had the 100W PA fitted and had probably only been used for a few hours.  It was in perfect condition visually, on arrival.  However, the Noise Reduction could not be engaged and attempts at RS232 connection in order to use the K3 utility software to store the configuration and perform firmware updates failed on both Mac OSX and Win 7 platforms, the former with both RS232 only and via a FTDI USB converter.  Googling provided little help although did indicate that the RS232 driver chip could get zapped in extreme conditions.  This was therefore changed on the KIO3 board without sorting the problem.  It was then discovered that connection via RS232 and USB ports and logging software worked perfectly.

Emails to the reflector and Elecraft produced advice but no definitive cure.  Finally, I took the rig to RATS and Steve G8LYB suggested doing a forced firmware upload.  IT WORKED.  All problems solved.  The cause of this foul-up may never be known.  The radio is not an SDR but does have extensive computer control which has been updated and improved over the years.

Since my rig was manufactured, there have been about 20 hardware modifications and improvements.  The rig will work perfectly well without these mods but I have done them all, except replacing the DSP board and getting the KSYN3A, obtaining most of the parts from Elecraft and a few from the UK.  Some surface mount and some leaded components had to be changed as well as PCB pins.  With the right tools, it was not too bad - just nerve-wracking when attacking the valuable main RF board!  These were very thoroughly documented by Elecraft.

To finish off the job I ordered the P3 panadapter kit along with the upgrade parts.  It is a superb addition to the K line.  Now, has anyone got a KPA500 and matching tuner they don’t want?


Couldn’t wait any longer - bought the KAT500 and KPA500 kits!  The build was relatively straightforward and once I got used to the controls and details of integration, all was fine.  Setting up the K3 to automatically change power if the linear is in ‘Operate’ is straightforward and avoids accidental overloading.  Training the KAT500 for each segment of every band takes a while but, once done, enables ‘search and pounce’ instantly (as long as the antenna is stable).  A couple of Hams on a net I work regularly, have antennas that use ladderline/windowline.  Everytime it is wet or a heavy dew, their SWR can vary a bit and sometimes upsets their automatic ATUs and/or linears.

Later in the year, odd things started happening.  Some buttons on the front panel of the K3 stopped working.  Then I remembered that early K3s can sometimes suffer from intermittent failure of the four rotary encoder push button switches  to the left of the main VFO encoder.  Multiple presses can cure the problem.  This worked for a while, but towards the end of the WWSSB contest in the autumn, the problem came back permanently.  £8 worth of encoders plus the same in postage were duly ordered from Aptos.  Fitting them was the most difficult desoldering, fettling and soldering job I have ever done, due to the close proximity of the main display and other delicate parts.  The relief when the rig woke up again was considerable.


More to follow on external frequency locking and XV transverters.


Updated 20 February 2016