Or that only vertically polarized signals can be intercepted by ships at
sea?

Chuck


Gary Schafer wrote:
On Wed, 17 Nov 2004 11:02:46 -0600, (Richard
Harrison) wrote:


Bob, K5QWG wrote:
"dunno know how big your boat is, but possibly a "tape-measure" dipole:"

A Go-Tenna is collapsible for easy packing, but twice as long as an
equivalent monopole, used against the sea, a near perfect ground.

A Go-Tenna can be deployed as a vertical and so could be effective at
sea but requires twice the altitude of an equivalent monopole.

Horizontal deployment requires an elevation of a couple of wavelengths
at sea to be very effective. That`s usually excessive.

Recall that the ground wave is vertically polarized. There is no
horizontally polarized wave propagation over the sea.

Terman says on page 808 of his 1955 edition:
"Examination of these vector diagrams show that with s perfect reflectoe
the horizontal components of the electric field will exactly cancel each
other at the surface of the perfect reflector. In contrast the vertical
components of the electric field of the incident and reflected waves do
not cancel, but rather add at the reflector surface with small values of
Psi 2 (the vertical takeoff angle from the surface)."

Best regards, Richard Harrison, KB5WZI



Are you saying that my low (less than 1/2 wavelength high) horizontal
antenna will be next to useless if I live on the sea shore? And that
same antenna will perform much better if I live inland where soil
conditions are poor?

73
Gary K4FMX