[BC] Re: FM bays

[Glen Kippel]

On Wed, Feb 11, 2009 at 2:49 PM, Cowboy <curt at spam-o-matic.net> wrote:

>
>  Personally, I like 6 to 8 bays, but can't really offer a good,
>  easy to understand explanation for why.
>
> ---------------

There are many factors to consider.  For instance, at Meadow Lakes,
northeast of Fresno, there is a smaller mountain between the transmitter
site and the city.  Four bays causes some of the signal to bounce off that
mountain and create multipath.  Six bays squirts the signal over the smaller
mountain for a cleaner signal.

Also, if you are on top of a mountain and your COL is close to the base of
the mountain, using 6 or 8 bays and some beam tilt may save on your power
bill.  That is, if there is no population beyond your COL, or it is in a
valley with mountains behind it that you don't want to excite with RF and
generate multipath.  But if you want to reach both the COL and out to the
horizon, broaden out the beam.  Check the depression angle to the closest
place you want to reach and then consult the antenna manufacturer's patterns
to see what will work.

Broadening out the vertical pattern too much can cause too much radiation to
hit the ground between the transmitter and the receivers and cause
multipath, too.