Richard Clark wrote:
On Sun, 17 Dec 2006 05:13:10 -0500, "Jimmie D"
wrote:

Roy I can kind of see this in a VOR with its rotating antenna but in ILS
systems(glideslopes and localizers) there is no moving antenna. They talk
about AM sidebands being formed due to space modulation.

Hi Jimmie,

I worked on this gear, and more, 30 years ago. Any discussion of
space was physical space. I was involved only with the
instrumentation, but the system specification is characterized in
terms of "signal-in-space." As such, the modulations vary by the
aircraft's position in airspace. This can be in terms of distance,
bearing, slope, or path. In some regions of space, the modulations
change from dash to dash-dot to dots. Shared with these are phase
relationships in both modulation and beam coverage. Testing of these
system parameters is tightly controlled so as to not create
hazardously misleading information to general aviation.

OM,

I'd appreciate any pointers you have to the FAA reference material that
defines "Space Modulation". Google shows only links to lists of training
courses that the FAA conducts, and references to "Pulse space
modulation", which I assume is a different thing.

TIA.

73,

William

(No cc: of ng posts needed, thanks)

--
A little learning is a dang'rous thing;
Drink deep, or taste not the Pierian spring;
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
-- Alexander Pope, Essay on Criticism