[BC] Engineering Advice

[Dave Dunsmoor]

> Until a few years ago, I didn't realize that one could define the FM bay
> spacing to anything desired without a special CP to achieve very specific
> vertical pattern results. Not just 1/2 and full.  The conditions and
> results can and will vary by location, terrain, and a host of other
factors
> which are generally unique to a site. So spacing is a factor to be
considered.

Hmmm, good point. One that I've not had to consider before just now either.
But it is identical to how the vertical guidance portion of the ILS is setup
upon
commissioning. If we were transmitting over a perfectly flat sheet of
copper,
the spacing above ground level would be ~ 14 and 28'. But it's NEVER that.

It's defined by lobe maximum and null, and determined by the location in
space by elaborately equipped aircraft, and we adjust the antenna spacing
(and several other parameters) to achieve exactly this.

Good insight, thanks.

Dave Dunsmoor