[BC] Bay spacing

[Mike McCarthy]

Warren is accurate.  And the tower situation we have here is certainly
unique. A one bay CBR does work quite nicely. But they're all at least
70ft. above the roof and the power density for RFR on the roof isn't an
issue with them even with all of the stations live. Their main lobe
doesn't hit the ground until about 1/2 mile from the site.  Which is great
for downtown applications if you have a 7-8ft face tower on which to mount
them.

However, a couple other sites more recently developed needed the tighter
vertical pattern and the mutiple bay reduced spacing option was really the
only viable option for them as they were limited to poles.  I suspect
Dana's situation is more in line with the latter than the former unless
they're going on an existing structure.

MM

> Richard,
>
> I agree with you on the single element.  A simple cosine function for
> vertical pattern can work in some applications.  This was a decision we
> made for the Sears (Willis) Tower in Chicago.  Each FM applied a single
> level cross-polarized dipole panel.  Throws a lot of energy with no nulls
> into the  downtown area.  Gain is 0.48 so you end up with TPO's in the 10
> kW range for 4 kW ERP.  Being 1,350 ft AAT is an oddity of sites for sure.
>  Ay not ne the best answer but for this application it works.
>
> Warren Shulz
> WLS A/F Chicago
>