The sectionalized vertical antennas mentioned by Richard Fry appear to
have been, perhaps still are, frequently used in VK land where distances
are great. Makes for a serious antenna.
73 Mac N8TT

--
J. Mc Laughlin - Michigan USA
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"Richard Fry" wrote in message
...

snip
Various types of "anti-fade" radiators are used by many of the 50kW
stations
to try to minimize this effect.

There is a tradeoff in the electrical height of the usual AM broadcast
transmit antenna between producing the greatest groundwave and
generating an
excessive high angle skywave that can interfere with that groundwave
at
night.

A 225 degree vertical is about optimum for groundwave, but has a high
angle
lobe that can cause this type of interference problem. A 195 degree
vertical has less groundwave but little/no high angle lobe, and so is
used
by many full time 50kW stations. WJR, Detroit is an example of a
station
using a 195 degree vertical (700 foot guyed tower).

Other antenna types also have been used for this, such as the
"Franklin,"
which is a sectionalized antenna with one vertical radiator above
another,
each driven separately.

Note also that the carrier frequency of the station, the conductivity
along
the groundwave path, and skywave propagation conditions will have an
affect
on the location of this zone, and the extent of interference there.

R. Fry
(WJR staff engineer, mid 1960s)