About three years ago my former brother in law Tom, WA4ZVL (SK) dropped by the house one day with a box of parts, a manual and a faint glimmer of hope. Tom had obtained a few scant parts for a K2 transceiver from an estate sale of a ham radio friend of his in Hopkinsville, KY.
I took one look at the box of parts all that Tom was able to obtain was an unfinished main PC board, a front panel, a circuit board for the front panel and a manual.
I looked at the remaining parts and asked Tom where was the rest of the kit? To my surprise he stated that relatives of the deceased ham had cleaned out his radio shack and apparently threw away parts and pieces of gear that they had no idea what they were used for or were part of any radios.
My reaction to all this was it was going to take some work and a lot of parts to be ordered. On the main board alone there are over 2200 components. That adds up to at least 4400 soldered connections considering that each part has two leads. Some parts as an example may have four leads and they could be transformers or coils.
Now before I go on with this article read the following carefully! If you are not experienced in the soldering of printed circuit boards. Unable to identify electronic components, do not have a temperature-controlled soldering iron, a solder removal station such as an electric vacuum pump, or the smaller soldering iron tips you are in trouble.
If you do not have a good volt ohmmeter, long nose pliers, small side cutters, proper solder, and although not necessary a signal generator would be nice. If you have none of these qualifications STOP. Go no further, either hire an experienced kit builder, or buy the preassembled model and not the kit. You will have more problems then you really need and become frustrated.
My first task was to check the front panel assembly and the PC board mounted in it, the first owner apparently had completed this board and it appeared to be a very good job. Just in case I double checked the instructions and after an hour, or so came to the conclusion I should set this board aside until it was needed in the construction.
The front panel board contains the microprocessor, plus the drivers for the LED readouts, a large chip in the middle of the board and smaller ones on the edges. The larger main PC board contains about 2200 parts that is a lot of through hole implementation add to this at least two connections as a minimum, some components have four, or more leads to solder and you have a lot of points to solder.
My next objective was to obtain all parts for the main board, Elecraft has an on line order form, but I opted to call the company and see if I could order an entire parts box for the main board. They were happy to meet my needs and in about a week a large box arrived at my house will all the parts I would need to finish the board.
The step-by-step manual is well written and contains pictures, diagrams and exploded views similar to the Heathkit manuals of decades ago. Those of you that were fans of Heathkit and I certainly was will recall how well their manuals were written. I think Elecraft took lessons from an old Heathkit manual. If you read the instructions, do what they tell you to do your rewards will be many once the product is finished.
I limited my self to about two hours a day of work on the project, that way I did not get tired and subject my self to wiring errors. I also had the time to double check my own work and inspect any connections for a good solder joint and no solder bridges between any traces.
I spent about a hundred working hours on the K2 and one day I installed the final part in the main board, this board contains everything to make a transceiver work with the exception of the microprocessor and the LED driver chips, they are on the front panel board. Not only are there parts on the top of this board, we also have numerous connections on the bottom requiring trace to trace soldering as well.
A few comments on parts sorting, Elecraft ships all parts in labeled small manila envelopes, part number printed on the envelope plus description of the part. Once I had all the parts for this board I stacked them in piles on my bench, resistors, capacitors, diodes, coils, transistors. This way I could refer to the part number on the package and match it with the required item in the assembly manual.
Some kit builders have suggested raiding your pantry for a cup cake pan, placing parts in the holes normally used for cupcakes. The point is the parts need to be sorted to ease your search for them when called for in the manual. Do not open the packages and dump all the parts on the bench, you will spend a lot of wasted time searching for the right part in the right holes.
With this completed I had to order the cabinet and the top to complete the project, plus mounting hardware the two boards connect to one another via a multiple header connector, be careful at this point no pins are bent and both ends align properly.
Once I received the hardware and the cabinet for the K2 things really began to take shape, I mounted the front panel and the main board to the chassis the project was near completion. If some of my readers are interested in seeing pictures of the progress drop me an e mail at either K4lrx@arrl.net, or k4lrx@att.net and I will send pictures of the project.
Alignment procedures were the next block of instructions and the first item to do was adjust the frequency of the microprocessor crystal. This is achieved by connecting the provided jumper to a plug in the upper left corner of the front panel this is the back view of the radio and you can see this plug in the picture. The other end is connected to the main board, by doing these connections it allows the front panel VFO readout to serve as a frequency counter.
The adjustment is a small variable capacitor and try as one might and I tried over a dozen times exact frequency specified is not easy, or nearly impossible to obtain. This does affect the accuracy of the VFO readout and I wound up with an 800 Hz error. Not a problem if you do not operate on the band edges, but be careful if you have the same problem.
On the initial turn on the following should happen, vfo should default to the lower band edge, LED’s on the front panel should light and some audio should be heard in headphones. All front panel functions should indicate with an Icon on the front panel they have been activated.
The next step was receiver alignment, if you have a signal generator and I do inject a small amount of signal at the antenna port. Keeping signal low prevents the I.F. coils from saturating; use the variable gain on the generator and the attenuator as well. In other words a small level of signal injected.
I also have an oscilloscope, so I set the audio control on the receiver to about half way and connected the probe of the scope to the audio out put jack.
I then began the process of tuning the I.F. coils and used the twenty-meter band Elecraft instructs you to peak for maximum . With the scope one can obtain a fine peak that may not show on the s meter indication. There is an alignment tool provided by Elecraft and it fits the slugs of the transformers.
With this task completed I was satisfied the receiver was working and proceeded to the next alignment step. It was suggested you align the s meter bar graph and this can be done by a couple of suggested ways. Set your signal generator to produce an s 9 level on a receiver, or other transceiver of known accuracy. Then move the generator to the K2 maintaining the same injected signal level and adjust the s meter to read s9. Use this method for the middle of the HF range, and twenty meters fit the middle of the available bands nicely.
The second method I cannot recall at this time since I no longer have the manual, or the K2, the finished product is in the hands of my former brother in law.
The final step was alignment of the driver coils and you will need a wattmeter and dummy load for this procedure. You place the RF power control maximum CCW, activate the cw mode, place short on the cw key terminals. Start with the lowest band and peak the coil for the maximum output, with the RF power control at maximum CCW the output on the wattmeter should be about one to two watts.
Repeat this procedure on every band with the proper driver coil for each band, every band worked with the exception of 17 meters. Upon some close investigation with a magnifier and strong light I found a small splash of solder on the output of the coil touching a ground rail at the same time.
Clearing this problem I was now ready to see what this rig could do on twenty meters with a good antenna.
This is where I found the good points and bad for this unit. Granted, the K2 is not an Icom 7800, 7700, nor is it a Yaseu 9000, or even a FT 2000. What you have at this point is a 10 to 15 watt cw transceiver, no the basic K2 does not contain a ssb exciter, antenna tuner, vox, or multiple antenna ports.
The K2 does contain cw filters, all band selection, large enough readouts and a clean transmitter. For nearly $800 not bad for the price, but let’s compare it to other rigs. By the time you add all the accessories, plus the 100-watt amplifier you will have spent about the same price, maybe more then you could have purchased a similar rig like an Icom, or Kenwood, Yaesu.
So how does the K2 perform with a large beam used for an antenna? I used my 5 element mono bander at 75 feet; I had tuned the band with my Yaesu 5k for some signals. The same signals on the K2 appeared to be down in strength, not near the front end of the Yaesu rigs.
The K2 lacks audio output on the receiver the claimed 1-watt output is not enough and if you select the cw filters the audio level drops even more. Raising the volume control results in an annoying audio hiss.
I also found the cw jack was intermittent and I replaced it with one of much better quality, the rig keyed fine, but again not enough audio output for the cw monitor and the receiver.
I found some strong dx signals and called them after they had signed with their contact, I also added QRP to my call just to see if I could raise a few stations. The band at this time was open to Europe and I had no difficulty working several stations in various countries of Europe. My reports ranged from 579 to 559, normally I receive 599 from my main rig and a couple of my contacts were stations I had worked many times with my main rig.
So, my evaluation of the K2, fun project, might use it for field expeditions, maybe portable operation, it can run on a DC supply and a car battery will run it all day since the drain at full 15 watts is 3 amperes.
Buying all the extras and that is the ssb exciter runs up the cost and in reality you can do much better with the big three. If you want the satisfaction of saying I built it, or have a learning experience then by all means get you one and go for it.
My brother in law did purchase the ssb exciter pre built and I assumed he did make a few contacts on ssb with this little rig. He did tell me that it worked fine and there were a lot of compliments on the clean signals it produced.
One more item to mention, the fast tune selection of the VFO produces and unstable tuning sound, in addition chirps result when the dial is tuned due to the fact you are hearing the digital tuning bits. In the slow mode no problem and unless you are moving from one end of the band to another the fast mode is of little value.
To be honest about it, I had fun building the K2, but I would have never bought one for my own use. Just not economical and I can find a small rig around the same price that will give me much more. Namely, the Yaesu FT 897, or FT 857 the choice is yours one has to question your wiring skills, patience and determination.
I do have praises for the people at Elecraft, they were helpful and anything that I ordered was shipped promptly and received with out any damage.
