Chinese Manual Days Antenna Tuner

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Cost: $12

Kit Contents:

Bag of parts, enclosure, labels, parts list, schematic


  • Assembly was straight forward except winding of the main toroid.  Fortunately there are a few other sites out there with good winding information and pictures.
  • Wiring of the trimmer caps was a little tight during soldering.
  • Holes had to be drilled in the enclosure but was easy enough to do with the provided labels.
  • The knobs provided use a strange combination of nuts, washers, and screw to secure them to the trimmer capacitors.

Operation and Comments:

  • The knobs keep working their way loose.
  • This was the first Chinese kit to totally fail for me (see Update below).  It seems to work but I loose half the power in both receive and transmit when using it.  Also the inductor switch only has an effect in the first 2 positions.  I can see the LED dim but only when the 2 capacitors are fully meshed.
  • Measured the 2 trimmer capacitors and they check good.  I have heard some complaints of non-working trimmers in other kits.
  • Re-wound the toroid twice.
  • I have even tried to re-wire it from a T to PI configuration with the same results.
  • Removing the LED meter board did not affect tuner performance.
  • Next step will be to remove the toroid from the switch and check the switch (forgot to do that on the second re-wind).  Also purchasing a better L-meter to check the toroid.
  • Update – It was a faulty switch!  Strange effect as the switch rings true on a continuity test but applying RF is a different story.  With the new switch it’s working as advertised.
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