DX Commander Build – Day 3

So its been another lovely sunny day down here in the QTH, but with a full day of work means a few hours in the morning and a couple in the evening to get things sorted.

Having done my analysis yesterday, I set about checking the mast. Whilst long winded, I had to be pragmatic and methodical in my approach to ensure progress was made.

  • take mast down
  • remove all wires
  • measure wire outside with long tape measure
  • compare to instructions, correct as required
  • mount and test
  • repeat for each wire

So having yesterdays results I took the mast down, which wasn’t too bad on my own given the mast is so light and guyed relatively low (well compared to the 2m/70cm mast which requires steps just to start! I disconnected all the wires, which was quite quick, then set about measuring the 30m wire.

With the accuracy of laying flat outside there was some 40cm of wire missing, so i cut some, re-soldered back on and reconnected, then re-erected the mast and radials.

I returned inside for testing with the NanoNVA – SWR still 5.5 – agggh ! What had I done wrong ?! so i went to check the basics, like connections,etc. All good there. I then tested the NanoNVA against the 2m antenna, SWR is fine. Then i though, could the other mast effect the DX Commander, surely not, but to make sure kept flipping the tester between antennas.. then it ‘hit’ me.. maybe i should recalibrate the NanoNVA for 30M. I set about doing that then…

30m – 1.76 SWR

Huzzah ! So, it maybe that I need to recalbirate for each frequency, or may not, anyway, to rule that out going forward thats what I’m going to do so the step plan becomes.

  • take mast down (leaving known good wire on)
  • measure removed wire, make corrections as required (lengthen/shorten)
  • re-measure wire to confirm length
  • attach to mast and erect
  • test previous frequency is still working on the correctly
  • re-calibrate NanoVNA for new frequency
  • test

Hopefully I will get the 40, 30 and17 completed today now i have a method, but another busy day of work is about to begin !

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