On 5 Apr, 10:32, Walter Maxwell wrote:
On 5 Apr 2007 10:05:43 -0700, "art" wrote:





On 26 Mar, 21:49, (Richard Harrison) wrote:
Art wrote:

"Any thoughts as to why it sgould be so and the scientific facts to
support it?"

We have plumb lines and bubble levels which allow easy determination of
vertical and horizontal directions.

We often inhabit a nearly horizontal plane

If we are as likely as not to communicate with any particular direction,
an omidirectional vertical antenna makes sense. An inclined wire would
favor some direction to the detriment of another. Sure a slopimg wire
works but doesn`t reach maximum height or length as effectively as a
vertical or horizontal wire would.

Why a straight dipole and not a V-shaped element? The V-shape corrupts
the nulls at the ends of the straight wire.

Vertical and horizontal antennas are not solely accidents of history.

Best regards, Richard Harrison, KB5WZI

Richard,
It is well known that near maximum "overall" polarity gain can be
obtained by placing a vertical at right angles with respect to earth.
Now -a -days maximum gain is required of a certain polarity which
requires a specific accuracy of less than 1 degree . So yes, in your
working years straight up is good enough but these days of WiFi and
all that concentration is applied for purity of polarity which
requires a resonance at around 3 degrees to the vertical. This can be
determined arithematically according to known laws. Ofcourse as one
moves higher this offset angle changes. This same phenomina or tilt
angle applies for all polarities where maximum gain is required for
purity of polarization.The days have gone where just putting up a wire
satisfies all.
Regards
Art

Educate me, Art, what is 'polarity' gain?

Walt- Hide quoted text -

- Show quoted text -

Walter
Gain is the total radiation at a particular angle which can be the
summation of all polarities such as in the case of vertical and
horizontal antennas.
If one want's maximum gain with a particular polarization in mind then
resonance is to be found at an angle other than 90 degree multiples to
the earths surface. This is why I have made the point for years that
the yagi has put antennas back nearly 100 years. In amateur work it is
not so important tho it does explain why the augument rages between a
yagi and a quad with the latter providing a much larger arrival area
that allow people to hear more. On top of that the yagi becomes less
efficient as one adds elements which means progressive polarity
inaccuracy for each added element not only for a particular polarity
but also for the increase in reactance for the array as a whole. I
have mentioned 3 degrees but that was only by the eye on print out for
a single element. I never did associate the tip angle with respect to
frequency and height tho I am sure this can be done via Matlab for
both a single element or an arrangement of elements.
One day they will put this in a book, hopefully the ARRL editions, so
the derogatory statements from the older education type guys will
cease but I am to old to see that day
Regards
Art