AM Stations Antenna Patterns
 

Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

Ted-

"Ted Jensen" wrote in message
...
Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

www.radiolocator.com (where you'll find it, and any other AM station in the US and
Canada)
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Ted,

Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

Plenty of them at www.radio-locator.com
--
Philip de Cadenet - London, SW3
Transmitters 'R' Us
http://www.transmittersrus.com

Does anyone know where I can obtain a plot of the antenna pattern for a major
(50,000 watt) commercial broadcast station?


Which one. There are several hundred which are 50 kW.

Perhaps the most interesting Class A pattern is WSAI's.

"Ted Jensen" wrote in message
...
: Does anyone know where I can obtain a plot of the antenna pattern for
: a major (50,000 watt) commercial broadcast station?
:
: Ted-
:

Check here.
http://www.radio-locator.com/

Ted Jensen wrote:
Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

Go to your local station and ask to look in the public inspection file.
There should be one there. If you ask the engineer nicely (and they are
a station that still has an engineer), he might also have some old proofs
so you can see how widely the pattern varies from year to year.

Be aware that the plot for a 50KW station on a stick in Montana will be
radically different than the plot for the same transmitter and tower in
Arizona. Which is what makes it fun.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Ted Jensen" wrote in message
...
Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

Do you want antenna pattern or station's coverage?

Pattern is easy. There are a number of on-line sources including the FCC's
AMQUERY. You can also download the whole AM database and display patterns
in my AMSTNS program available (with very recent data) from
http://home.earthlink.net/~lvehorn/

Coverage is hard, since interference from other stations is involved - a
simple field strength prediction is not adequate. The only RELIABLE source
I know for interference-free coverage is to look up the station's actual
application on the FCC's AMQUERY.

73 de bob w3otc

"Ted Jensen" wrote in message
...
Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

www.radio-locator.com

Note that the maps are careful labeled "for entertainment purposes." They
are not totally accurate,a nd very,very, very exaggerated. On AM, the only
useful contour is the innermost circle... and it is actually bigger than
reliable reception areas really are in most cases. The outer two circles are
totally meaningless.

This only assumes you are in the US, one of few places where "major" and
"50,000 watt" are synonymous.

On 3 Oct 2004 00:29:17 GMT, Ted Jensen wrote:

Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

Go to www.fcc.gov. There's an AM database that has the information and
patterns for all stations.

Rich

Does anyone know where I can obtain a plot of the antenna pattern for
a major (50,000 watt) commercial broadcast station?

www.radiolocator.com (where you'll find it, and any other AM station in
the US and
Canada)
____________________

The contours shown on Radiolocator.com are based BOTH on the radiation
pattern of the transmit antenna system, and ground conductivity along
various radials for 360° around the transmit site.

If conductivity was a constant throughout the groundwave coverage area of
the station (almost never happens), then from the "patterns" on
Radiolocator - to the extent they are accurate - you could calculate the
actual shape of the transmit antenna radiation pattern, remembering that
field strength changes as the square root of changes in radiated power.

RF

Visit http://rfry.org for FM broadcast RF system papers.