[BC] RF absorption by foliage

[Mike McCarthy]

Greg Buckwald showed in his presentation at Madison that the pattern 
skewing in an Ibiquity system will cause stations to emit signal higher 
than authorized in certain azimuths.  Presuming the same would apply to the 
mask, I can't imagine the Ibiquity signals meeting the mask if the 
reference AM carrier is used to center the mask.

My little grapevine has told me that AM IBOC is in deeper trouble at the 
FCC than FM.

MM

At 05:52 PM 10/30/2005 -0500, Tom Bosscher wrote
> >Wonder if with IBOC the FCC is going to make DA's broadband
> >their arrays to keep all the IBOC trash to the same pattern as the
> >main channel? Be fun to measure that!!
>
> >Looey Munn
>
>    Looey, that question has been asked a lot. By law, does an AM IBOC 
> stations have to comply with the NRSC mask, at ALL azimuths? Since the 
> Ibiquity system is based on slight of hand of a sideways, but legal 
> reading of the rules, Ibiquity's AM IBOC should have to live by those rules.
>
>    I've asked before, and it will be 3 weeks before I have time to do it 
> myself, but has anyone measured NRSC compliance of a DA Ibiquity AM 
> array, "around the horn"? Is the only place NRSC measurements are allowed 
> is the TX common point? Funny, the FCC measures AM NRSC compliance away 
> from the towers.
>
>    I have personally talked to one am engineer who has made the 
> measurements. He will not release the pictures of the AM station he 
> checked on, as they are his client, but he did admit that this DA came no 
> where close to being compliant at several points of azimuth.
>
>
>    I am not anti Ibiquity AM IBOC. I am fully interested in the rules 
> being applied fairly and uniformally.
>
>    Any "Pro" DA AM IBOC stations that would like to step forward and 
> offer their arrays to be analyzed and results published? Or maybe you 
> have and you pass?
>
>    My guess is that a simple and properly designed two tower DA should be 
> OK. After that, I would not put my money on the investment risk.
>
>
>       tom bosscher
>
>
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