Re: More 'PIDS'

["Alex Borodin" <yaropolk@hotmail.com.au>]

David,

I would suggest ( and this is really sticking my neck out) that the amount
of Amps the trains use has no bearing on the ability of our systems to
display information clearly. The difference is how we have designed our
transmission and display systems.

I suggest this because we have had faulty trains before which were drawing a
heck of a lot of current and which were also sending out heaps of EMF. The
picture quality on our surge-protected systems remained unchanged. The CRT
tubes weren't affected (probably because they are shielded, grounded, and
are too small to act as a suitable inductor.

Indeed, I would suggest that the systems in Melbourne and Sydney are prone
to EMF not because of the CRT's receiving too much EMF (plasma screens would
have a similar problem in that a great enough EMF would cause the phosphor
dots to light up and flicker)  but because of the video transmission
method.. No, the EMF (even in Sydney or Melbourne) is not great enough to
affect a CRT at that distance.

If we used the transmission method they use, we would have the same
flicker/distortion problems as experienced at Spencer and Flinders Sts in
Melbourne, and in various locations in Sydney. I know this because we had
the same transmission system in place at Toowong Station for many years on
the older CRT-based system and it did the same thing. The new PIDs at
Toowong does not.

The new PIDS at Toowong is still CRT based, and is (in places) even closer
to the traction cabling than the old. No distortion. No noise. Just nice,
crystal clear video. The answer lies in the innovative way in which we
cost-effectively transmit our video signals over long distances, with many
drops and over standard (cheap) copper cable. Now I'm sounding like a
salesman.. :-)

Best regards,

Alex Borodin
Software and Systems Engineer
Signal and Operational Systems
Queensland Rail



David Johnson wrote in message <374EB461.41E72D20@ozemail.com.au>...
>Alex Borodin wrote:
>
>> Brisbane has normal TV-type CRT's and we have no distortion (at all) even
if
>> we get a faulty spark go by which draws heaps of current and radiates
quite
>> staggering amounts of EMI.
>
>Your EMUs have a different traction control system to ours, which may
explain
>why ours gave problems.  Just as an example, your trains might pull 100
Amps at
>full load, where ours pull thousands of Amps.
>
>--
>David Johnson
>CityRail Guard
>trainman@ozemail.com.au
>http://www.ozemail.com.au/~trainman/
>
>