[BC] Bay spacing

[Mark Humphrey]

Until the policy was revised in the '90s, the FCC did not allow the
vertical component of an non-commercial FM directional antenna to
exceed the horizontal component at *any* azimuth.   I ran into this
problem in 1988 when we moved WRTI to a new tower in Philadelphia --
our antenna manufacturer had to reduce the maximum vertical ERP so
that the measured Vpol pattern was completely contained within the
measured Hpol pattern.  The vertical RMS also had to be less than
horizontal RMS, and this is still a requirement except when TV 6
protection is required.

The explanation given to me at that time was that the pre-CDBS FM
database only provided a place to enter the horizontal pattern
tabulation, as measured on the range.    By forcing stations to adhere
to that policy, there was no need to show a separate vertical
tabulation.

However, under current policy, the database shows a "composite"
pattern envelope which neither measured component can exceed.

Mark

On Tue, Feb 21, 2012 at 9:26 PM, Ron Youvan <ka4inm at gmail.com> wrote:

>> I remember someone in California who wanted to use vertical-only because it favored automobile radio reception --Jackson, Caifornia. At the time, it was the FCC's interpretation that the vertical component could not exceed the horizontal component so if you have no horizontal component..... 'nough said. The FCC may have loosened up a bit nowadays because of the great success with vertical polarization in Europe.
>
>   Naw, just their typically non-engineering inconsistent.
> --
>    73 Ron KA4INM - All E-mail sent to this address shall linger in the Google cloud forever!