"John Rumm" wrote in message
...
dennis@home wrote:
"John Rumm" wrote in message
o.uk...
This does not tally with the installations I have seen locally. The wall
outlet box may or may not have a filter etc I don't know never having
looked in one.
How do you know it doesn't tally if you have never looked?
I have looked at the splitter, and by design that is all that it is, a
splitter not a filter...
However the splitter they supply was a bog standard off the shelf F type
RF splitter.
They are all off the shelf parts.
You can even buy the cable headends if you can aŁŁord them.
It does not matter where that is inserted or what equipment is connected
to which leg of it after the main wall port. (in fact as I accidentally
discovered the other day it works with two of them in circuit and 30
yards of dangling unterminated co-ax hanging off one side. (customer had
forgotten last time they had cable before moving out for renovations
they had it split to deliver a cable to an upstairs room as well!)
That is the purpose of them, to balance the lines and cut down
reflections, etc.
If we are still talking about the splitter, then that is twaddle. The
splitter is similar to:
I have never been talking about the splitter, however a properly designed
splitter is a filter designed to maintain the impedance across the outputs.
Even the cheap ones usually have a star network of resistors to give some
sort of balance.
http://cpc.farnell.com/labgear/fbs40...ass/dp/AP02109
You may get away with chopping the cable before the first filter, you may
not, it is different for each installation.
If there is a filter, it will be in the wall outlet plate - which is the
first termination of the cable on entry. Which I fully accept (depending
on the content of the wall plate), you may have problems interfering with
the cable before that.
However since the cable length on the consumers side of the wall plate is
variable, and the splitter may not even be present, it seems pointless
bestowing mystic powers on the splitter.
I accidentally did something similar with a thin net, as a result some
computers could not see others and it was different for each computer. It
caused null points as the reflections caused by the impedance change
cancelled the signals out.
Indeed it might - a completely different situation however. Thin ethernet
is a CSMA-CD technology that relies on subtle cable voltage sensing to
maintain the contention detection. DOCSIS as used over CATV networks is a
TDMA system giving deterministic access.
You missed the point, the problems were caused by impedance mismatches
causing some bits of the network to not see the signals while others could.