On Oct 2, 12:58 am, Bill Horne wrote:

What puzzles me is the ground: I don't understand why such a wire would
function as anything but, well, ground. I

I think it's really about ground (dirt) conductivity. Which varies all
over the place.

In some places (moist, loamy soil with lots of minerals, coastal areas
where the water table is very high and salty) the dirt is a pretty
good conductor, to the point where antennas "worked against ground" do
pretty well with just a ground rod or two. RF just bounces off that
sort of dirt.

In other places (dry, sandy, rocky soil) the dirt is a very lossy
counductor, and acts more as an RF absorber.

With a low dipole, the ground is so close that it has major effects on
the antenna. If it's lossy dirt, it just soaks up RF, but if it's a
decent conductor, it can act as a reflector. The added wire is just a
way of improving the ground conductivity in the dirt that is most
involved: the dirt directly under the antenna.

73 de Jim, N2EY

Hi O,m's
interresting things around here about groundwires at a dipole
in my reply of the 3.5mc vertical i told that an antenna can bee seen as a
coil and a condensor
tuned at working frequencie
a run of wire has an inductance remind the stripline tuned circuit at vhf
if we have a normal tuned circuit coil and capacitance it is understandable
we see the parts
if the coil is a length of wire a litle less but if we remind uhf circuits
if we move the condensorplates to the top and bottom of the coil we can see
still the tuned circuit
and we have a new experimental antenna type google H antenna for more
details also commercial available
even precooked building instructions very interresting to understand the
basics of antennatheory
if we strech the coil we got the wireantenna where is the condensator hi
the wiresurface to earth
now we can understand that the dipole is a serial combination of two coils
and 2 condensators and a thirdth to earth
notice that there are 2 radiation paterns a magnetic from the coil and a
statthic from the condensator
so it is to understand that a groundwire under the dipole has an influance
at the capacity of the antenna and also at its radiation
the groundconditions of our garden chances rain moisture sun etc
the condition of the diged wire will not chance and the results of the
antenne too.
i hope i cleared a little
73 de ruud PA0RAB

schreef in bericht
...
On Oct 2, 12:58 am, Bill Horne wrote:

What puzzles me is the ground: I don't understand why such a wire would
function as anything but, well, ground. I

I think it's really about ground (dirt) conductivity. Which varies all
over the place.

In some places (moist, loamy soil with lots of minerals, coastal areas
where the water table is very high and salty) the dirt is a pretty
good conductor, to the point where antennas "worked against ground" do
pretty well with just a ground rod or two. RF just bounces off that
sort of dirt.

In other places (dry, sandy, rocky soil) the dirt is a very lossy
counductor, and acts more as an RF absorber.

With a low dipole, the ground is so close that it has major effects on
the antenna. If it's lossy dirt, it just soaks up RF, but if it's a
decent conductor, it can act as a reflector. The added wire is just a
way of improving the ground conductivity in the dirt that is most
involved: the dirt directly under the antenna.

73 de Jim, N2EY