"Chuck" wrote in message
news:n5gdd.8202$6P5.3752@okepread02...

wrote in message
news:x_Ycd.281755$3l3.162866@attbi_s03...
What brought this to my attention was Moxon who advocated 2 element
beams
(lightnes translates to greater heights) so I modeled a 20 meter beam on
a 7
foot
boom and obtained 12dbi max for the band (ala 2:1)

Hi Art,

Can we assume this gain was calculated
at a particular height over ground?
But ofcourse a perfect ground and a standard wavelength height

Personally, I prefer FS results, in order to
eliminate any ambiguity.
Field strength (F.S.) introduces ambiguity does it not?


but one can get 13dbi
if you drop the impedance from 50 to 12 ohms.

This paraphrases the spesific example that I gave

the question would a transformer cancel the increased
gain.
Again you paraphased the spoecific sample that I gave
which raised the same question I gave regarding transformer losses

Optimizing an antenna for a specific Z
is not a good idea in my opinion, as
the amplitude of an element's current is
proportional to the amplitude of its
radiation. Ohms law tells us that at a
consistant power level, the lower the R
(Z), the greater will be the current.

Yes there are many laws to remember and I
look at critical coupling as something to remember.



A zero loss transformer would not
reduce the element's current, as the
energy being introduced to the element
would remain unchanged.

Very true but what element would this max energy be applied to?
Via critical coupling the driven element may not be the one carrying
the maximum current and thus screws up conventional thinking.
Energy is one thing but it is current that controls radiation is it not ?.
The particular model I was working on used 50 segments per wavelength
and used element length and diameters determined by my program input .
Thus coupling gains are attained but where it sometimes determined a
element diameter
is so thin it is incapable of carrying the required current.
If I saw a vendor advertise an antenna at 13dbi I would be very suspicious
as it not the norm,
yet very realiseable when using NEC without being tied down to existing
doctrines.
Sooooooo ..... I was looking for a datum curve generated by experts from
an all encompasing
NEC program where the final design reflected the real world design without
ambiguities
regarding coupling to coils, elements e.t.c. where lumped loads do not
reflect the real
world appearance.
There have been many responses including one suggestion that a suitable
datum curve could
be formulated from customer claims no less but NONE that responds to my
specific request .
Thus a conundrum still exists regarding programs based on scientific
knoweledge that are held in question
as they do not match real world measurements that spawn most of the
villifying in this group.
Seems like a datum curve could be used as a basis for many discusions where
differences do occur
instead of just arguing for eight years or more and not resolving the
accuracy concerns
Seems like I have come full circle and describing the Presidential debates !
Art

73 de Chuck, WA7RAI