RE: Multidrop KAT5 AV Daisy Chain

[Keith Doxey]

Hi Mark,

Is your AV point at a different location to your Node 0 ?

Any sources that dont need physical media to be changed can be located
anywhere as can the switcher.

Regarding Wireless - If the transmission is done as analogue then it would
have to be composite video as there would not be a high enough bandwidth to
support multiple video signals each modulated onto different carrier
frequencies so the quality would not be as high as you currently get from
KAT5.

If the signals are sent as digital then there are different compression
algorithms that can be used to minimise the bandwidth but any form of
compression loses quality. Uncompressed digital video is something like
216Mbit in a studio and can easily be compressed down to around 34Mbit
without any noticable loss in quality. Sky digital often uses 2-4Mbit for
their channels and the artifacts can often be seen on some channels
particularly during fast moving scenes.

The biggest problem with any form of wireless is that there is only a
certain bandwidth available and that is shared by anyone in the vicinity.
The more data you try to send through the air, the more likely it is that
you will get corrupted data. Whilst this can easily be detected and resent
it slows down the throughput and also increases the traffic leadign to more
collisions etc.

Although a cable has a finite bandwidth you can double the available
bandwidth by running another cable along side. Run 100 cables and you have
100x the bandwidth available. That cant be done with wireless.

Whilst wireless technology is expensive, the takeup will be slow. As prices
drop it becomes more popular and congestion of the airwaves gets worse.

This happened with Analogue cordless phones, initially very expensive so
very rare and little problem with interference. Prices dropped, more people
got them and they had to introduce extra channels and security coding to
prevent people making calls on other peoples lines.

Although I do have a vested interest in wired solutions it is also backed
up
by the fact that a wired connection is by far the most reliable method of
connection.

Keith

www.diyha.co.uk
www.kat5.tv


> -----Original Message-----
> From: Mark Fulford [mailto:<a
href="/group/kat5-users/post?postID=Dyw9mNBDxLUMyCOZyey1traxrk8BLIj1ToAbtJksEQLNzVpyUtTEeMKFVtZtHMnAXhgtcFYe-B8">mark@v...</a>]
> Sent: 03 June 2003 17:55
> To: <a
href="/group/kat5-users/post?postID=bjeH3G5YISPDbhIKvpkZX_6qsrfadSfr13el8aDGqcyNWfvCOokfRv20DIKA4Ml6qGiHQ4F27yranHD4CnGmBM3DvtaH">kat5-users@xxxxxxx</a>
> Subject: Re: [KAT5] Multidrop KAT5 AV Daisy Chain
>
>
> Looks like I may be struggling to implement multisource. When
> I had my house built I put 8 coax cables to my A/V point, but
> only 2 CAT5. One CAT5 is split between IR and Sky telephone
> and the other is already used for KAT5. Well, they do say you
> never have enough points.
>
> I am thinking that in the not too distant future, the way to
> do this will be with a disk based A/V server in the loft,
> together with Sky box and digital tv box, linked to TVs, PCs
> etc. Your KAT5 technology will be a vital part of that. In
> the meantime, I am more than happy with multisource and
> multizone - albeit one at a time.
>
> One other question. Do you have a view on what kind of speed
> wireless networking will have to reach to support the same
> quality of output as wired?
>
> Mark