[BC] Daytime IBOC, Nighttime C-Quam

[Chuck Hutton" <charlesh3@msn.com]

Kevin:

I never dreamed anyone would think my query had anything to do with
almost-as-dead-as-General-Franco C-QUAM.

I can answer my own question below: Section 4.7 of the document "1082sDc HD
Radio AM Transmission System Specifications" says that the analog audio
input must be monophonic.

I'm curious about broadcaster's reactions to this. It's my understanding
that this is the first time iBiquity said the hybrid AM mode would be mono
and never anything more. Right or wrong?



Chuck



Message: 9
Date: Sat, 16 Jul 2005 13:32:53 -0700 (PDT)
From: Kevin Tekel <amstereoexp at yahoo.com>
Subject: [BC] Daytime IBOC, Nighttime C-Quam  (was: RE: IBOC - AM
	stereo)
To: broadcast at radiolists.net
Message-ID: <20050716203253.8721.qmail at web54609.mail.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1


 > Do I recall that NRSC-5 mentions only a mono service for AM? Or was my
 > quick scan mistaken?

As I understand it, the NRSC-5 standard only applies to IBOC stations.
So if you're not using IBOC, then nothing has changed -- you're still
allowed to transmit full 10.2 kHz NRSC audio, in C-Quam AM Stereo or
Kahn POWER-side, if you so choose.

Meanwhile, you can't transmit hybrid AM IBOC and C-Quam AM Stereo
simultaneously because both systems make use of quadrature modulation,
but at night when the digital sidebands are off, IBOC stations are free
to transmit C-Quam AM Stereo.  Radio Disney affiliate 1110 KDIS in the
L.A. area is rumored to be setting up this kind of daytime-IBOC /
nighttime-AM Stereo scheme for their signal.  Numerous other stations
have the capability to transmit either AM IBOC or C-Quam AM Stereo at
the flip of a switch, but KDIS would be the first to use both systems
on a daily/nightly basis.