Optical audio connections
 

In article , Phil Allison
scribeth thus

"tony sayer"


OTOH - a co-axial line **inherently rejects** all such interference.


Can you explain in your own words..well perhaps tone it down a bit;, how
thats so?..


** A loop ( or coil ) of wire will both radiate and receive an alternating
magnetic field.

Think of hearing aid loops, loop antennas etc.

A length of co-ax will do neither - cos it simply has zero net loop area.

Due to its symmetry.



symmetry ??..

... however the screen is part of the source and is in circuit is it not
in unbalanced operation?..

--
Tony Sayer

Optical audio connections
 

** The twisting is more elaborate to reduce loop area and magnetic field
injection.



A few years ago for an RSL broadcast the local cable company supplied us
with a few stereo circuits over 3 miles of normal copper phone cable and
apart from a slight HF loss .. no hum or other disturbance AT ALL!.

And that cable was hardly twisted in construction .. nor was it screened
even!.
--
Tony Sayer

Optical audio connections
 

"tony sayer"


** The twisting is more elaborate to reduce loop area and magnetic field
injection.


A few years ago for an RSL broadcast the local cable company supplied us
with a few stereo circuits over 3 miles of normal copper phone cable and
apart from a slight HF loss .. no hum or other disturbance AT ALL!.

And that cable was hardly twisted in construction .. nor was it screened
even!.


** Being underground supplies the all the RF and AC supply hum screening
needed for those lines - a couple of metres of damp soil is very effective.

BTW: Phone cables ARE twisted to suppress crosstalk with other pairs in the
same bundle.

Got ** SFA ** to do with cables installed in the walls an floor of a house
that will inevitably run near or even in parallel with AC mains wiring or
triac dimmed lighting wires PLUS have to cop full exposures to powerful
modulated RF sources like GSM phones.




...... Phil

Optical audio connections
 

"tony sayer"
Phil Allison


OTOH - a co-axial line **inherently rejects** all such interference.


Can you explain in your own words..well perhaps tone it down a bit;, how
thats so?..


** A loop ( or coil ) of wire will both radiate and receive an alternating
magnetic field.

Think of hearing aid loops, loop antennas etc.

A length of co-ax will do neither - cos it simply has zero net loop
area.

Due to its symmetry.


symmetry ??..


** Cannot be explained without diagrams and math.

But a simple test will prove it anytime.


.. however the screen is part of the source and is in circuit is it not
in unbalanced operation?..


** Yawn......


Try to figure out what twisting a pair of wires does & why four wire
twisting is does it better - then just accept that being co-axial has a
similar effect.



........ Phil

Optical audio connections
 

"Phil Allison" wrote in message
...


** Being underground supplies the all the RF and AC supply hum screening
needed for those lines - a couple of metres of damp soil is very
effective.

What makes you think all phone lines are run underground?. My phone is
connected to the exchange via 4 miles of overhead cable, oh, and it carries
ADSL as well.

BTW: Phone cables ARE twisted to suppress crosstalk with other pairs in
the same bundle.

And have been since 1880 or thereabouts. Of course telephone exchange
equipment balances the impedance to ground as well. Telephone engineers
quickly discovered just how important that was for suppressing interference
from electrical power supply systems and electric traction.

Got ** SFA ** to do with cables installed in the walls an floor of a
house that will inevitably run near or even in parallel with AC mains
wiring or triac dimmed lighting wires PLUS have to cop full exposures to
powerful modulated RF sources like GSM phones.

And you think telephone wires don't? What planet do you live on?

It's clear that you have no idea what you are talking about. I've used
unscreened twisted pair to carry line-level audio in domestic premises as
well as cinemas. There are *far* fewer problems with interference from such
sources as there is when attempting to use unbalanced co-ax.

David.





..... Phil

Optical audio connections
 

"David Tosser "
"Phil Allison"

** Being underground supplies the all the RF and AC supply hum screening
needed for those lines - a couple of metres of damp soil is very
effective.

What makes you think all phone lines are run underground?.


** Stereo circuits that give near perfect audio quality would be.

That claim was in the context you just snipped out of sight - arsehole.



Got ** SFA ** to do with cables installed in the walls an floor of a
house that will inevitably run near or even in parallel with AC mains
wiring or triac dimmed lighting wires PLUS have to cop full exposures to
powerful modulated RF sources like GSM phones.

And you think telephone wires don't?


** Funny how phone circuits so often hum, buzz, hiss, crackle and sound like
absolute crap.

It's clear that you have no idea what you are talking about.


I've used unscreened twisted pair to carry line-level audio in domestic
premises as well as cinemas. There are *far* fewer problems with
interference from such sources as there is when attempting to use
unbalanced co-ax.


** Funny how domestic hi-fi audio uses co-axial type cables exclusively and
with great success then.

It's clear that you have no idea what you are doing or talking about.

****wit.



...... Phil

Optical audio connections
 

In article , Phil Allison
scribeth thus

"tony sayer"


** The twisting is more elaborate to reduce loop area and magnetic field
injection.


A few years ago for an RSL broadcast the local cable company supplied us
with a few stereo circuits over 3 miles of normal copper phone cable and
apart from a slight HF loss .. no hum or other disturbance AT ALL!.

And that cable was hardly twisted in construction .. nor was it screened
even!.


** Being underground supplies the all the RF and AC supply hum screening
needed for those lines - a couple of metres of damp soil is very effective.

Around a third of that was overhead. A final part was by BT overhead and
next to power lines at 11 kV..


BTW: Phone cables ARE twisted to suppress crosstalk with other pairs in the
same bundle.

They Have slight twists but nowhere like what CAT 5 cable does..


Got ** SFA ** to do with cables installed in the walls an floor of a house
that will inevitably run near or even in parallel with AC mains wiring or
triac dimmed lighting wires PLUS have to cop full exposures to powerful
modulated RF sources like GSM phones.

BTW can you tell us how Valve circuits are susceptible to RF as yet?..
--
Tony Sayer

Optical audio connections
 

In article , Phil Allison
scribeth thus

"tony sayer"
Phil Allison


OTOH - a co-axial line **inherently rejects** all such interference.


Can you explain in your own words..well perhaps tone it down a bit;, how
thats so?..


** A loop ( or coil ) of wire will both radiate and receive an alternating
magnetic field.

Think of hearing aid loops, loop antennas etc.

A length of co-ax will do neither - cos it simply has zero net loop
area.

Due to its symmetry.


symmetry ??..


** Cannot be explained without diagrams and math.

Stop avoiding the question...

But a simple test will prove it anytime.


.. however the screen is part of the source and is in circuit is it not
in unbalanced operation?..


** Yawn......



Stop yawning you dozy sod and avoiding the question..

Try to figure out what twisting a pair of wires does & why four wire
twisting is does it better - then just accept that being co-axial has a
similar effect.


No I won't as it don't!..


....... Phil



--
Tony Sayer

Optical audio connections
 

"tony sayer"


** The twisting is more elaborate to reduce loop area and magnetic
field
injection.


** You ignored this one too.


A few years ago for an RSL broadcast the local cable company supplied us
with a few stereo circuits over 3 miles of normal copper phone cable and
apart from a slight HF loss .. no hum or other disturbance AT ALL!.

And that cable was hardly twisted in construction .. nor was it screened
even!.


** Being underground supplies the all the RF and AC supply hum screening
needed for those lines - a couple of metres of damp soil is very
effective.


BTW: Phone cables ARE twisted to suppress crosstalk with other pairs in
the
same bundle.

They Have slight twists but nowhere like what CAT 5 cable does..


** Cat 5 is high speed data cable - so it needs a high twist rate.


Got ** SFA ** to do with cables installed in the walls an floor of a
house
that will inevitably run near or even in parallel with AC mains wiring or
triac dimmed lighting wires PLUS have to cop full exposures to powerful
modulated RF sources like GSM phones.


** Lack of acknowledgement noted.


BTW can you tell us how Valve circuits are susceptible to RF as yet?..


** Are you too dumb to figure out why an input valve might demodulate a
strong RF signal ??

RFI predates the transistor - you know.

Dickhead.



...... Phil

Optical audio connections
 

"tony sayer"


** Cannot be explained without diagrams and math.

Stop avoiding the question...


** Go do your own ****ing test - arsehole.

Then go drop dead.



..... Phil