"Joe Subich, W4TV" <lists@subich.com> wrote:
> On 1/5/2024 12:53 AM, Robin wrote:
>
> > One thing to bear in mind throughout any analysis of such designs for
> > 160M is that the total focus of the Broadcast designs and measurements
> > and proofs is energy at zero degrees elevation. Our needs benefit from
> > low angle radiation, for certain, but, little attention is paid by the
> > broadcasters and by the modeling programs to position and shape of
> > elevated lobes, or for that matter, the shape of the main lobe above
> > zero elevation
> Not exactly true. Many "modern" broadcast facilities are designed to
> minimize high angle lobes that cause destructive *self-interference* at
> the outer edges of the [night time] ground wave coverage.
>
At an MF broadcast station station I worked at 50+ years ago a qsy of
200KHz HF had been made. Severe fading was then encountered at the edge of
the service area at night from a high skylobe. About 200 feet was lopped off
the top of the 550' tower, which restored the fringe area reception.
--
Brian D
G3VGZ
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