Interesting topic.
As the old saying goes, a good dipole is hard to beat.
A 40m dipole approximates 3 1/2 wavelengths on 15m, giving two bands for the
price of one, if you can tolerate somewhat higher SWR on one of the bands.
Have been told that adding small inductances either side of the feedpoint
can give low SWR on both 40 and 15 but have never bothered to model or
experiment along these lines.
BTW, the cloverleaf pattern from a three half wave dipole is a pretty useful
pattern in most parts of the world.
Any one remember the famous RCA 'Spiderweb" antenna, widely used by SWLs and
commercial receiving stations through the 30s and 40s.
Could be interesting to rework one for the hf amateur bands. Has the
advantage of separating the dipoles with minimum of hardware.
73
Barry ZL1DD
--
Barry Kirkwood PhD ZL1DD
barry.kirkwood@gmail.com
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