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I have a hex beam antenna that gets me onto bands from 20 meters to 6 meters very well.

I wish to have an antenna that gets me onto 40 meters at night very well also.

Recently I purchased an end fed long wire antenna with a 9:1 unun. This one : https://www.ebay.com/itm/272675235910

The fact that the wire length is only 41 foot in length, this means that it is about a 1/4 wavelength at 40 meters. Is this ok?

Would it make sense to get one longer at about 66 foot, so that it would be a half wavelength at 40 meters instead. Much improvement? Thanks in advance.

Engineer999
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  • This is one of those cases that a complete Answer will duplicate the work captured elsewhere. This is well-discussed at places like https://sm7uzy.se/art/the_end_fed_long_wire_project.php (which has a nice chart and advice about chokes and ununs -- both of which are recommended). And the end of the day, this sites suggests that ~20m of wire with the right feedline system is a sweet spot for 40M. Not suprising, given how mults of $\lambda/2$ is a rule of thumb for these kinds of antennas. –  Mar 23 '22 at 14:50

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With a 9:1 endfed, you don't want it to be a 1/4 wavelength at any band. The reason for this is because the 9:1 transforms your roughly 400-900 ohm load into something close to 50 ohms. If you want more antenna length, somewhere around 53-59ft should work well.

Richard Hum
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  • Thanks for your reply. The length of wire with the antenna I bought is 41 foot. I should perhaps extend this to around 58 ft perhaps. I want to have decent antenna for DXing on 40 meters. – Engineer999 Mar 24 '22 at 08:53
  • A bit off topic, but would placing a choke balun at the feed point to the 9:1 unun be a good idea? I see mixed feelings over this – Engineer999 Mar 24 '22 at 08:55
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    @Engineer999 that sounds like a different question! –  Mar 24 '22 at 18:45