FreeLists / opendtv / [opendtv] Re: Check SAP on FOX during NASCAR Race

["Dale Kelly" <dalekelly@xxxxxxxxxxx>]

Dan wrote:
> can there be a direct pass through?  Perhaps they are getting an ATSC
> encoded feed, but wouldn't that need to be converted to NTSC for
> the analog transmission?  Or does the exciter get the same digital
> stream and spit out two signals?

I had previously written:
> I did confirm that Fox feeds affiliates using a 19.3MBs ATSC stream
> which includes additional muxed program stream(s). They supply
> an equipment package which includes a splicer to cut between
> network/local per the stations network log. The spliced output
> directly feeds the stations DTV transmission system.

Fox provides stations a rack of equipment with 4 receivers, two are their SD
feed (analog program) main and backup. The third and fourth are main and
backup DTV Rx that feeds a Fox splicer for the DTV program, the second input
to the splicer is from a Thales mux carrying the local stations unconverted
ASI signal. The output of the Fox splicer then feeds the twin stream*
microwave.

* The twin stream microwave feeds both the analog and DTV signals to the
transmitter site. This method is not universal, some use separate microwaves
or other distribution methods. The point is that FOX provides to it's
affiliates a self contained DTV MC system and there is no base band signal
and the analog program is not derived from the DTV feed


> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx
> [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of John Shutt
> Sent: Wednesday, June 13, 2007 10:01 AM
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: Check SAP on FOX during NASCAR Race
>
>
>
> ----- Original Message -----
> From: <dan.grimes@xxxxxxxx>
>
> DG:  I was able to do a couple of other tests which show that it is coming
> from KVVU that way.  I monitored the SAP off Cox Cable and Off
> Air and both
> were the same and only SAP had the problem (main and mono were fine).
> Other programming has the same issues, but not as bad as the NASCAR races.
>
> HO: NASCAR race  -  Monday, June 4, 2007  12:45pm - 1:00pm
> Same compliment of audio on all three services - Stereo, SAP, Monaural.
> All have complete commentary, music and sound effects.
> The SAP channel has about 6 db lower level, reduced frequency response
> range and a clipped type tick, tick noise every few seconds which often
> correlates with audio edges-say raised voice, etc.
>
> JS:  "Main" and "Mono" are one and the same.  The main audio is
> mono, then
> there is a separate L-R audio that is DBX compressed that is used
> to allow
> the receiver to create stereo audio.  There is a third carrier
> that is also
> DBX compressed and bandwidth limited for the SAP channel, which is why it
> usually sounds so lousy.  There is also an optional fourth channel called
> PRO which is even further bandwidth limited, intended for use as
> a studio to
> field talent backchannel.
>
> DG:  Yes, but unfortunately I am always out of the house during the live
> races.  But with the rain delay at Dover, I was able to watch it live at
> work off of Cox Cable and Off Air.  So now I know it is a live problem and
> not a VCR problem.
>
> I did talk to the Chief Engineer at KVVU.  He said it is a direct pass
> through from the Fox satellite through Master Control to the transmitter.
> He said he was going to check it in Master Control.  I asked if he would
> call me back to tell me what he found, but has not up to this point.  But
> can there be a direct pass through?  Perhaps they are getting an ATSC
> encoded feed, but wouldn't that need to be converted to NTSC for
> the analog
> transmission?  Or does the exciter get the same digital stream
> and spit out
> two signals?  I would think that the Master Control equipment would work
> with SDI, perhaps with embedded audio, but would need to go to an ATSC
> encoder before the exciter.  But I don't have any experience with a Master
> Control for an ATSC transmission, so I cannot speak to this.
>
> JS:  Any "direct pass through" has to go through a BTSC audio
> generator of
> some sort.  We use Orban Optimods, as does the majority of
> broadcasters who
> broadcast BTSC (or MTS) stereo audio.  The SAP channel of the Optimod has
> level adjustments and compander settings that can easily cause
> the breathing
> audio that you're experiencing.
>
> John
>
>
>
>
>
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