Still getting software back up and running on the new PC at the moment, with MMANA-GAL the latest to be restored.
Usefully, the software comes with a ready-made model of a rhombic for the 10m band. Somewhat unusually, it consists of legs each 0.75 wavelength long (so each half of the antenna has wires 1.5 lambda long).
To model my own antenna, all I have to do is rotate 90 degrees about the X axis to create a vertical antenna. Over near-perfect ground at HF that is found at the coast, this is a very satisfactory approximation to what I can expect in reality.
Here's the surprising output, totalling over 12dBi gain, which seems a lot higher than we might expect, although ground settings are set to perfect:
The horizontal beamwidth is remarkable! No need to worry about lack of geographical coverage with this antenna (which, it should be noted, is an unterminated version; the terminated version should see half the pattern more-or-less vanish).
This is all rather encouraging for a 14MHz version, where it seems unnecessary to make an enormously long antenna to realise excellent gain figures. New roll of wire awaited with enthusiasm!
No comments:
Post a Comment