| This antenna was primarily
designed as an 80M antenna, but I love DX-ing on 40 CW and couldn't resist adding a 40M
element. A 35 ft #14 wire was run from the feed point up the side of
the vertical to just below the coil. The wire was offset from the main
mast using vinyl covered aluminum tomato stakes available from ACE hardware. These were connected to scrap aluminum plates and U bolted to the main mast.
The wire is offset from the mast by about 14". The wire was separated from the aluminum
stakes using insulators. The wire
was tied off at the top and at the bottom and was allowed to float freely in
the middle 2 insulators. The wire was trimmed to resonance around
7100khz. The result is a radiator that covers the entire 40M band
under 1.7:1 SWR, and is around 1.3:1 at the low end, which is my primary
interest.
The antenna in general is a good performer. The 80M bandwidth is excellent with under 2:1 from 3500 to about 3870 khz. The resonant freq is about 3600. The antenna is presently over about 1000ft of #14 radial wires, which is about a 13-15 ohm (moderate) ground plane. The antenna is also close to resonance on 30M, with an SWR of about 2:1 across the 30M band. It can easily be loaded and does a good job on this band as well. |
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