EFHW Matchbox Wackiness

As I mentioned in the previous post, I had completed the EFHW matchbox and tested with a fixed 1.8 K Ohm resistor with the 6:1 turns ratio. I decided to try and setup a wire for 20m. I connected a 10m wire and a 1m counterpoise and started getting some strange results. Basically, I was getting no results.Adjusting the wire length didn’t cause a significant response nor did adjusting the cap. I was starting to wonder if I should have gone with a higher turns ratio. It was fairly easy to change the ratio as all I had to do was remove one leg of the secondary and pull it through the toroid. I opened up the matchbox to do this and all my sloppy work came back to bite me. The wire to the center of the UHF connector broke off and I noticed a loose solder joint to the capacitor.I really should have taken my time with these connections but I was rushed to finish the matchbox.

Lesson learned…

I did change the turns ratio to 9:1 and changed all the wiring in an attempt to reduce the stray capacitance. I put everything together again and tested the matchbox as before with a 3.9K Ohm resistor across the antenna terminals.The results were very similar to the 6:1 ratio settings. I hooked up the antenna wire and counterpoise and this time noticed a response. The wire is still needing to be tuned but I expect that it will work this time. The capacitance did change and I am just able to tune 10m but 40m is still out of range.I need to make some measurements and check my capacitor wiring but I am sure I can get this working on 20m now for some testing. Hope to get this on the air on the next go around.


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