[BC] FM antenna radiation patterns

[DANA PUOPOLO]

Why?
How about because you WANT a distorted pattern because you want to concentrate
your signal where the population is.

I consulted a Massachusetts FM station 15 years ago. Their TX was located
about 40 miles west of Boston on a hill known for great FM transmission. They
had a rototiller antenna pole mounted, and a fly around showed it's pattern as
an almost perfect circle, both H and V....

Which was exactly what they DIDN'T WANT!  

Why? Because 10 miles west of them was the Quabbin reservoir and nothing/no
one!  All the people lived EAST of the transmitter, in Boston and its
suburbs.

We used a ring stub antenna and came up with a pattern that put 35% nore
vertical field east then the rototiller. The difference was dramatic...the
station can now be heard in places where it didn't exist before and its signal
is MUCH better where the people live.

-D

 

------ Original Message ------
Received: Fri, 20 Jan 2006 06:40:20 PM PST
From: "Steve Michaels N4AY" <steve at stevemichaels.net>
To: "'Broadcast Radio Mailing List'" <broadcast at radiolists.net>
Subject: [BC] FM antenna radiation patterns

I am curious-after looking at Richard Fry's paper, it would appear that the
ring-stub radiator has a drastically different pattern from the rest.
Without using names (they will be obvious from his presentation) why would
anybody want that design?  I don't believe everything I see or read, but
this seems kinda wacky..  

 

The website is rfry.org  presentation link on the bottom of the page
pertaining to zero sidelobe antennas.

 

And I do apologize for what may have been an issue addressed before.

 

TNX,

Steve

 

 

 

 

  

 


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