... have not been able to hear the nets that I am told are occuring to the south of me.
How far south, and on what frequencies? What time of day?
For any path there will be times that it works on some frequencies and doesn't work on other frequencies.
That depends on the current state of the ionosphere and the operating frequency.
A couple useful tools for propagation predictions:
http://www.voacap.com/prediction.htmlhttp://www.ips.gov.au/HF_Systems/7/1Before you blame the problem on your antenna, make sure that propagation supports that frequency for
that path at the time of the net. Note that the results won't exactly agree, but they can give you some
good clues as to what to expect.
A dipole doesn't show much directivity at relatively high angles (shorter path lengths) but will show more
directivity at low elevation angles (longer path lengths). However, I've never found the pattern to be
that sharp - I had a rotatable dipole up for 10/15/20m and after trying to turn it to optimize signals I
finally just left it fixed, as it appeared to work about as well.
If you decide that you do need to change your antenna and the path length is a few hundred miles,
you might consider extending just one end of it by half a wavelength instead. That puts a strong lobe
in the direction of the wire at about 30 to 60 degrees elevation angle. I've had good results with
such a pattern over distances of 200 to 500 miles.