[BC] Re: SUPER MODULATION & AM STANDARDS

[Phil Alexander]

On 12 May 2005 at 10:18, Lamar Owen wrote:

> So it's not really an interference issue in the positive modulation 
> direction; it's a sidestepping of coverage limits.  You raise the sidebands 
> up and you get more distance to effective reception.  And you walk on your 
> co-channels' sidebands, as well as you first adjacents' carriers.

Back in the days when the FCC Broadcast Bureau was run by Harold Kassens, I
think you might have gotten a different opinion regarding the fact that it
WAS an interference issue. This probably was the reason for the RM that led
to the limit of 125%, a truly insignificant amount from an interference 
standpoint in the adjacent channel consideration. Remember that there was
no NRSC frequency limit in those days and modulation in the 12-15 kHz range
was relatively common in most plants. There was a time when adjacent channel
interference was taken quite seriously. Alas, there are few today that recall
those times and none of them are on the Commission.

Phil Alexander, CSRE 
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037




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