RadioBanter - View Single Post

October 30th 03, 05:02 PM

On 30 Oct 2003 08:43:23 GMT, (ARDUJENSKI) wrote:
Hi Alan,

As an aside, we all know the ground plays an important role in the antenna
performance yet it seems there is very little effort on behalf of the amatures
to measure actual ground conditions near and far field. Getting back to the
parasitic radials, TUNING ther verticals at least allows us to compensate for
this unknown.

Tuning and ground should have no relation except in Q. The tuning is
for the benefit of variable phase delay and the proximity of ground is
going to blur that distinction causing the F/B to back fill the null.

I know in Reg's antenna programs I generally assume AVERAGE ground conditions
or about 20 ohms to be on the conservative side. What would be nice is some
sort of set up that you could tune the antennas by use of an audio sound. It
seems in theory that you could connect a receiver to the vertical driven
element and have a signal source a few hundred yards away or more and tune the
forward for max volume and a signal from behind for min volume and strike a
happy medium....Alan

That sounds rather complex. How are you going to hear the sounds,
loudspeakers? Won't the neighbors mind? Remember, if you are close
enough to hear, you are close enough to upset the tuning. I suppose
you are trying to accomplish this solo, but keep in mind that near
fields (those within 1 wavelength radius of the elements at a minimum,
3-5 wavelengths modestly, 10 conservatively) do not geometrically
represent the launch characteristics observed in the far field (which
dominates all our activities).

73's
Richard Clark, KB7QHC