From: bob@eagle.inmos.co.uk (Bob Green)
Newsgroups: uk.misc
Subject: Re: Cable TV quality
Date: 22 Dec 92 09:54:27 GMT
Distribution: uk
Organization: INMOS Limited, Bristol, UK

In article <BzM84z.GrC@fulcrum.co.uk>, igb@fulcrum.co.uk (Ian G Batten) writes:
|> In article <BzM42H.79F@micrognosis.co.uk> jharuni@micrognosis.co.uk writes:
|> > When watching a one of the usual UK TV stations, can you view teletext ?
|> > On all four channels ?  Do you get more or fewer errors than with your
|> > aerial ?  Do you get NICAM via cable ?  Do you get more or fewer
|> > sound dropouts ?
|> 
|> OK.  This all confused me before I installed cable.  Note this is the
|> information for Birmingham Cable.

And this is for United Artists in Bristol:

|> 
|> The output from the cable decoder carries distinct UHF carriers for the
|> terrestrial channel, plus a UHF carrier for whichever ``cable'' channel
|> you have selected.  Confusingly, there are TWO copies of each
|> terrestrial channel available: one on its own carrier, and one available
|> by selecting the appropriate channel on the cable decoder.  The
|> canonical set-up appears to be having pre-sets 1-4 on the TV and video
|> set for the carriers of the terrestrial channels as output from the
|> cable head and pre-set five set to the extra channel.

Ditto

|> 
|> Nicam is available on the terrestrial channels when taken via their own
|> carriers, but not for anything else.  Teletext is provided throughout
|> --- it's just lines.

We get stereo sound in a different way: as well as UHF channels, we get VHF audio
channels dow the cable, including Radios 1-4, local radio and Satellite radio. In
addition, the sound for some satellite channels (movies etc) and the four
terrestrial stations is available as a VHF channel. So, I simply connect a second
cable from the cable head to my FM receiver, tune it in, and off I go. 

|> 
|> I watch the cable channels by taking the composite video and audio lines
|> from the cable decoder and plumbing that into a SCART selector box.
|> Irritatingly, the decoder is US made and therefore doesn't have its own
|> SCART and does provide SELECT.

You lucky thing ! United Artists don't have the technology to get video and sound
directly from the cable box - it just pumps out RF.

|> 
|> The distinct carrier signal for the terrestrial channels is pretty good.
|> My house has direct line-of-sight to Sutton Coldfield, about ten miles
|> away, with a well aligned aerial and the signal I get from that is
|> slightly better.  But I can watch the TV with a fully acceptable Nicam
|> signal by putting my finger over the end of the aerial lead --- no
|> shortage of signal --- so my experience my be atypical.  Since I get
|> almost as good quality from the cable as an essentially perfect
|> reception rig, for anyone in less ideal conditions it will be better.

I live at the bottom of a hill in Bristol and the reception/picture quality from
the cable is better than anything I ever got from my aerial on the roof !

|> 
|> I very rarely see any text glitches.  Except last night --- for some
|> reason the Teletext off Sutton Coldfield was almost unusable, whilst the
|> cable was OK!  I suspect faults at the transmitter...

Don't have teletext, so I can't comment.

|> 
|> The terrestrial signal made availble by the cable selector is softer, of
|> course.
|> 
|> ian
|> 
|> 

-Bob

-- 
| Bob Green          Inmos Ltd, Bristol       bob@inmos.co.uk
|                                         or  bob@inmos.com        
|The opinions above are the rantings of a madman and therefore could
|not possibly reflect Inmos policy.