john smith wrote:
In article ,
the Legend of LAX wrote:

They did some flight checks on the new ILS
last night. It's getting the new fangled end-fire glideslope.

Does that mean it directly projects the gs instead of reflecting it from
1000 feet down the runway?

For a little background explanation for those who don't know how it works:
The antenna sits at the touchdown point (the point where the glide path
actually touches the r/w), 750-1250 feet down the runway & offset
250-650 feet from centerline. It projects a beam toward the the landing
path at an angle of 1.4 (usually) degrees. We use capture effect now,
which is based on the principle that a receiver will lock on to the
stronger of two signals & reject the weaker. I have not been to school
for the end-fire so I don't know its theory yet, but it does basically
the same thing, just using a different method. The antenna sits at about
the same point. Instead of being on a tall mast, it sits almost flat on
the ground, similar to a localizer antenna. It is used where terrain is
not smooth (since the CEGS uses an image antenna as part of its
operation & requires smooth ground plane around it to reflect the
image). I will try to get some pictures & post them showing the
different antennas.

--
Dale G Elhardt
Cypress Ca
"The universal aptitude for ineptitude makes any human accomplishment an
incredible miracle."
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