KAT5 AV Units - Update (Was : RE: Re: CAT-5 wiring details)

["Keith Doxey" <keith.doxey@xxxxxxx>]

Hi All,

I was going to delay this posting for a while but since Nigel has brought
up
the subject again, here goes....

My wife Sharon has gone to Spain for a week with her sister and left me at
home babysitting. This has given me some of the much needed time to do
further work on the KAT5 AV Units. Today I had a meeting with a PCB
manufacturer to check that my CAD files were compatable with their
manufacturing processes....they are :-)

I now have guide prices for various sizes and quantities of boards. The
biggest problems so far have concerned sourcing the right parts at the
right
price. I could find lots of good looking cases but they cost more than the
bits I was going to put in them!

The units I showed to the guys in London were housed in small plastic boxes
that were an attactive price but extremely difficult and time consuming to
machine. It was also dificult to cram all the components in neatly. I have
now sourced some slightly larger boxes. They are "Instrument
Style" cases
with removeable front and back panels that are much easier to work on.

I hope to have the latest prototypes up and running after the weekend and
will probably go back to the PCB manufacturer for a final quote on Tuesday
next week. All being well I should be in possesion of professionally
produced boards by the end of October. (They currently have a 20 day
delivery time).


These are comments I have sent to Mark over the last couple of days.

**********

The prototype S-Video units I showed the guys in London had a couple of
faults on them due to the difficulties of home produced PCB's but after
fixing those I have just been watching DVD in S-Video upstairs in the
bedroom via CAT5 from the lounge. Picture quality is EXCELLENT :-))

**********

I have spent the evening doing some further tests on the S-video KAT5
units.

Set up the following in the lounge.
Got my HA PC KHAN and used its ATI RagePro card as a video source.
Resolution set at 800x600 using both Composite and S-Video outputs.
Fed into AV Amp and from there into the KAT5 unit.

Upstairs TV 25" JVC. fed via KAT5
Windows Explorer perfectly readable from about 10feet in S-video and pretty
good in Composite (some moire patterning on the fine text but games and
browser looked fine with a suitable text size)

Downstairs TV 28" Mitsubishi fed direct from PC
Not as good as JVC. Fault of TV not PC. Screen geometry and convergence are
WAY OUT !!!
Trivial Pursuit was pretty good though. A 28" TV and surround sound
amp is
MUCH better than a laptop. I bet a 7foot projector is even better ;-)

Then came the real test for quality.....
There are loads of SCART leads that suffer bleed through from the video out
to video in. I have a 2 metre SCART to 6phono lead that is diabolical even
though there are 6 separate coax cables in the outer sheath. When I was
putting the 12 TV's above the bar in the Long Bar I couldnt run the coax
cables next to each other because they would interfere with each other
causing slight colour distortion.

S Video is basically 2 separate video signals, one for a black and white
picture containing all the brightness info (Y or Luma) and the other
containing the colour info (C or Chroma). The 2 pairs used to carry this in
the CAT5 can be used for 2 composite signals instead. Infact, the Video
Conferencing version will be just that. 1 audio and 1 video circuit in each
direction down the same cable.

To test the immunity to interference I decided to send 2 different video
signals over the circuit.

L	Left Audio - DVD Left audio - JVC AV2 Left
R	Right Audio - DVD Right audio - JVC AV2 Right
Y	Composite Video from DVD - JVC AV2 Composite

C	Composite Video from KHAN - JVC AV3 Composite

Upstairs I was able to select AV2 on the TV I could watch a crystal clear
DVD picture in stereo with no interference whatsoever. By selecting AV3 I
had a clear picture of the KHAN desktop with no bleedthrough of the DVD.
Obviously neither was as clear as they were when fed in as S-Video but the
picture was easily as good as if the source had been right next to the Tv
and connected via a SCART lead.

************

The first units available will be Transmitters and Receivers for Composite
or S-Video with Stereo Audio. They will be used one on each end of the CAT5
cable for a single source. The next units to be available will be the video
switcher cards to form a central hub for the system.

Once the new boxes are done I will photograph them and put them on my
website for you all to see.

Must go.....PCB's to redesign.

Keith


> -----Original Message-----
> From: Nigel Orr [mailto:Nigel.Orr@xxxxxxx]
>
>
> To be honest, I find balancing and differential drives are much more
> effective at rejecting interference than screening, so
> it's probably fine to wire it all in UTP and then add drivers (KATV!)
> if/when you find you need them (and Keith finds time to make them!)
>


-------------------------- eGroups Sponsor -------------------------~-~>
GET A NEXTCARD VISA, in 30 seconds!  Get rates
as low as 0.0% Intro or 9.99% Ongoing APR and no annual fee!
Apply NOW!
http://click.egroups.com/1/9331/9/_/2065/_/970178738/
---------------------------------------------------------------------_->