Antenna Spool with 1:64 Balun

Added a Balun to my original design. Now the spool is a full blown Half Wave Endfed Antenna!
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updated August 24, 2023

Description

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I wanted to integrate a Balun into my antenna spool for a long time, now it is here!

I created this antenna winder for SOTA activations, but of course you can use if for non-sota activities as well. The balun I wound has a 1:64 ratio, but of course you can wind it however you want.

We made many these antennas in the ÖVSV Antenna Workshop in OE6 because the price per antenna was lower than 10€!

The toroid should be capable of 100W SSB and 50W CW according to multiple internet sources. All the knowledge for half wave endfeds will not fit on this page, so here is an excellent source if you need to know more: https://www.nonstopsystems.com/radio/frank_radio_antenna_multiband_end-fed.htm

You'll need:

  • 1x spool
  • 1x both caps
  • 2x rope tensioner
  • 1x BNC adapter for chassis mounting with solder point on back.
  • 1x FT140-43 toroid 
  • 90cm of 0.8mm enamel wire
  • 2-4m Paracord (3mm diameter max)
  • Antenna wire of your choice (used 0.25mm for my 10W QRP transceiver)

Instructions:

  • Check the cap lids and their protrusions before you wind the toroid. The final balun should snug in just right.
  • Mount the BNC connector
  • Use the holes on the cap to run the antenna and counter poise inside.
  • Solder everything together
  • Use leftover enamel wire pieces to lock the caps. Or glue them together if you prefer that.

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The author remixed this model.

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