[ARDF] Collapsible pole verticals

[Kuon & Dale Hunt]

Sam wrote:
>We are using the ground wave at that distance, not sure that the finer
>points of 80 meter antenna design will help much. Maybe someone knows
>what we could do to improve our signal at a distance of 3 km versus 3000 km?


   Actually, both distances use the same techniques.  (If not, the
   AM broadcasters would be doing something different to improve
   their ground wave coverage.)  Within the range of practicality
   for ARDF antennas, here are the steps to maximize signal strength:

   1)  Use vertical polarization.
   2)  Make sure antenna is properly resonated.
   3)  Reduce ground losses.  (Usually this means
         more and/or longer radials, since it isn't
         practical to use elevated radials.  But a
         ground-independent design such as a short
         vertical dipole could help.)
   4)  Improve antenna efficiency.  The Q of the loading
         coil is a major contributor.  Center loading the
         antenna might help somewhat.
   5)  Use maximum power, though 3 - 5 watts should be
         plenty, even with relatively poor antennas.


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