[BC] FCC Approves proposed AM MoM Rules

[Thomas G. Osenkowsky]

If the FCC attempted to regulate pattern BW
it would be one *BIG* can of worms! Many
existing arrays cannot meet IBOC or good
quality audio standards with their existing
geometry. Towers would have to be moved,
removed or additional ones built to meet
FCC specs at carrier as well as sidebands.

Each array is different. A given change in phase
and/or ratio at the same upper/lower sidebands
will produce different field intensities at the same
amount of azimuth change. This depends on how
deep the null is or the size/shape of the minor lobe.
Recall that not every null protects another station i.e.
multiplied arrays.

How would one prove the pattern BW to an
inspector? Most consultants use network analyzers.
You can also change the tx freq and observe the
antenna monitor (if it is not frequency sensitive).

When I redesign a feeder system, I will usually opt
for better pattern BW than impedance BW since the 
latter can be corrected using external networks. 

As I said, a true can of worms!

Tom Osenkowsky, CPBE

> Question for those really familiar with the new Rules: Does this 
> expand, in any way, the bandwidth over which the pattern must be 
> held?  (In other words, does it do anything about the radiation other 
> than at carrier?)