On Thu, 10 Jul 2003 19:04:29 -0600, \"Sparky\" wrote:

| I still wonder about that AM tower I once passed in Santa Clara,CA
that was sitting on a salt marsh right at sea level....do they have all
that wire in the ground, er, water, too? Not sure on that one.

There's no AM tower in Santa Clara (or at least none in the last 40
years that I know of), let alone one that meets that description.
There's one in Palo Alto (1220 kHz) and yes, it has the standard
120-radial ground system. The ground there isn't all -that- wet.

In "the good old days" the radials were 8 AWG copper, but after
several stations got their ground systems torn out by thieves who
sold the copper on the scrap metal market, almost everybody replaced
them with 8 AWG Copperweld, which has the same rf electrical
properties but has no value on the scrap metal market.

I haven't ever seen AM towers with salt marsh surrounding it,

There are several other AM stations in the Bay Area whose antenna
arrays are located right at the water line. In those cases, the
radials go out from the base and into the Bay, which is tidal.

but in that case they sure would put out a much better signal than a
tower located away on dry rocky ground with all the buried radials.

The ground system and conductivity are but two elements in the
antenna efficiency. Other factors are the electrical height and the
spacing and phasing of elements in a directive array.

AM antenna design is more of an art than a science.

--
73 de K2ASP - Phil Kane