Building the ARRL 40m - 10m EFHW Antenna Kit

I got this EFHW antenna kit (https://www.arrl.org/shop/End-Fed-Half-Wave-Antenna-Kit-for-10-15-20-40-Meters/) from ARRL about a month ago and finally got sometime to work on it. ARRL does provide a instruction page (http://www.arrl.org/end-fed-half-wave-antenna-kit) which should be sufficient for folks with prior experiences. However it is not really good/detailed enough for a total rookie/newbie like me. The antenna is actually from HF Kits which provides a much better instruction (https://www.hfkits.com/build-instruction-impedance-transformer-250w-for-end-fed-antennas/) with more detailed step-by-step higher quality pictures, which helped a lot!


TL;DR of the list of things I could have known better for building this antenna from the kit:

  • Locations of the holes to be drilled:
    ARRL instruction only mentions to drill about 1/2 inch away from the top of the closure. If you are not be careful enough (or not experienced enough to know how) like me, you might start drilling on the wrong sides. Take a close look at the photo (from HF Kits instruction page) below, the holes for the SO-239 etc shall be drilled on the sides without the holes for the screws to fix the transformer.

  • The rubber coats around the 3 wire connectors: it turns out you do not really need them. The wires, including the leads of the capacitor can be wound around the screen and to fastened to make the connection work (with help of some soldering). Or you can peel of the rubber coats out before you install them as shown on ARRL instruction photos. This will make the process much more pleasant.
  • Building the transformer
    • The wiring can be seen more clearly from the illustrations from HF Kits rather than ARRL instruction page

    • As to the sanding/scraping the insulator of the copper wire, all the four ends of the wire shall be sanded/scrapped to expose the metal core for better contact. The part where the two ends needs to be soldered together, it's much easier to sand/scrape the whole part instead of just where you will solder.

So far I have only finished the UNUN build, the antenna wire has not been attached and no test has been done yet. I will try to get this out when weather allows and see how my build works and in the worst case, I may have to take apart everything and redo it as now I have better idea what the appropriate actions and their sequence are :)


73


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