Thread: Dual-Z0 Stubs
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Old April 29th 09, 08:59 PM posted to rec.radio.amateur.antenna
Jim Kelley[_2_] Jim Kelley[_2_] is offline
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First recorded activity by RadioBanter: Jul 2008
Posts: 16
Default Dual-Z0 Stubs

On Apr 29, 5:09*am, Cecil Moore wrote:
Jim Kelley wrote:
Cecil Moore wrote:
Itot = Imax*cos(kx)*cos(wt)


Noting the linear variables and constants in there, and the absence of
anything that would change abruptly at certain particular values of x,
what would the expression for a standing wave on a shortened coil loaded
90 degree monopole have to look like?


Ideally, it would be of the form:

For x = 0 to top of coil,
Itot = k1*cos(k2*x)cos(wt)

For x = bottom of stinger to top of stinger,
Itot = k3*cos(k4*x)*cos(wt)

where k1-k4 are constants

Note: The above is a conceptual simplification as it
ignores the current "bulge" in a real-world loading
coil.


It ingores almost everything about the antenna.

Note that at the coil/stinger junction:

Itot = k1*cos(k2*x)*cos(wt) = k3*cos(k4*x)*cos(wt)


Uh, what units did you say your constants k1-k4 had again?

- as required by the laws of physics.


Is that supposed to automatically add credibility to any remark which
preceeds it? Thusly, the nano-particles emitted by the framistat at
an impedance discontinuity carry only re-reflected energy - as
required by the laws of physics. It does sound impressive.

10*cos(0) = 14.14*cos(45) = 10

The above phasor has abruptly rotated its phase by
45 degrees and increased its amplitude by 41% with
no violation of the laws of physics.


Cecil -

Mathematics is NOT a toy.

:-)

ac6xg