Radios

Articles and blogs about radio receivers and transmitters. Both commercial off the shelf radios and home made DIY experiments by Alexandru Csete OZ9AEC.

K1 VFO Checks

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The VFO range check is perfect. Without needing to do any modifications, not even squeezing or sopreading the turns on L1, I have a VFO range between 2.993 MHz and 3.094 MHz. The VFO seems as stable as a VFO of this kind can get. There is a frequency shift of 1 kHz down if … Read more

My K1 is Alive!

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Tonight I continued with the combined tests of the RF board (part 1), front panel board and filter board. All tests up to the VFO test are ok, including LED/LCD, error codes, sidetone generator, voltmeter, keyer and filter board relays. On the picture below you can see the very first thing K1 says, when no filter board is found.

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Successful Filter Board Tests

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After completing the assembly of the K1 filter board, I have done the resistance checks on the board. All checks tests passed perfectly 🙂 The next step will be to proceed with the tests of the RF board and then the combined tests and alignments of the RF + filter boards, which in fact is … Read more

Coils for the Filter Board

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I have just finished mounting the coils onto the K1 filter board. It turned out that some transformers need their secondary to interleave with the primary, on the contrary to what I mentioned earlier. I guess it depends on the function of the transformer.

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K1 Filter Board

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I have finished mounting all parts on the filter board, except the inductors and plugs. I was surprised by how badly some of the capacitors fit in the holes. It is not quite what I am used to from Elecraft but it’s really no big deal. Maybe the capacitors don’t fit because the original ones … Read more

The K1 is Taking Shape

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After mounting L2, T1 and T2 on the RF board, it was time to mount the side panels on the RF board and mate it with the assembled front panel board. This has to be done before the receiver alignments and it is really cool, because I can now see the K1 taking shape:

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More RF Board Progress

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More progress with the RF board. I have mounted all the crystals on the board. Next step is to wind some toroids. At this point the assembly manual explains that when windind toroid transformers, it is okay for the secondary to overlap with the turns of the primary and they need not be interleaved. That … Read more

K1 RF Board progress

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I have made some further progress with the RF board. Everything went fine and both the resistance and the voltage tests are perfect. In the mean time I also had to fix my soldering iron, which had a bad connection inside the iron. Well, it is at least properly soldered now :o)  

Stop for Today

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No matter how exciting it is to assemble the K1, I feel I have to stop now. I’m getting quite tired and I don’t want to make any mistakes. Not on the K1!

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K1 Front Panel Finished

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Hmmm… After finishing the front panel I have three resistors left:

  • 330 ohm: This one was an option for low intensity backlight, saving a few milliamps.
  • 220 ohm: This one is sitting in the strip, thus it should be part of the standard assembly. Very fishy, since it is not even listed in the parts list. Maybe it was originally intende for the high intensity backlight?
  • 100k: THere are four 100k resistors listed in the parts list, all four of them is mounted.

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