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Default Highly Shielded Audio Cable

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!









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Default Highly Shielded Audio Cable

In article ,
"Ralph D." wrote:

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Look for a cable TV-coax (RG-6, maybe) that has a continuous foil shield.

Isaac
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Default Highly Shielded Audio Cable

In article , Ralph D.
writes

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.


Off-the-wall suggestion: run them through a length of copper pipe or
through that flexible metal conduit used in electrical installations?

You'd probably want to earth (ground) just one end to be sure a ground
current didn't flow, causing interference.

--
(\_/)
(='.'=)
(")_(")
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Default Highly Shielded Audio Cable


"Ralph Dope"

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.



** I have a sense of "deja vu" about this question ?

Is the signal stereo or mono ?

A 20 foot long 3.5mm two core cable is not gonna be easy to find at all let
alone with different qualities.

BTW:

Do you REALLY have a problem or are you just imagining one ?

How about some details ?

The solution may NOT be what you have guessed it to be.



..... Phil



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Default Highly Shielded Audio Cable

On 03/09/2014 08:30 PM, Ralph D. wrote:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!



What type of input does the transmitter have? Balanced +6dB? Unbalanced
50 Ohms? If it's Balanced, use transformers at the send end, or a
balanced line driver (aka Direct Box) of some kind (2 for stereo).
Ground only the receive end of your shields. Use as much "send" as you
can get away with; this will reduce noise at the xmtr input.



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Default Highly Shielded Audio Cable

On 3/9/14 23:49 , isw wrote:
In article ,
"Ralph D." wrote:

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Look for a cable TV-coax (RG-6, maybe) that has a continuous foil shield.

Isaac




For this application, you'd want a cable with at least a 95% braid shield.

A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.


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Default Highly Shielded Audio Cable

On Mon, 10 Mar 2014 08:24:12 -0700, D. Peter Maus
wrote:

...snip...

For this application, you'd want a cable with at least a 95% braid
shield.

A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.




might look into high quality cabling like Belden 1800F
John Woodgate in UK and I worked together to extensively analyze that
cabling and exploring 'weaknesses', have LTspice models and he has a lot
of application data.
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Default Highly Shielded Audio Cable

In sci.electronics.repair Ralph D. wrote:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.


get some electrical conduit.


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Default Highly Shielded Audio Cable

The Lady from Philadelphia suggests...

Have you tried using an inexpensive cable //simply to see what happens//,
rather than assuming you //need// a highly shielded cable?

If it doesn't work, you could encase the cable in braiding, grounding the
braiding at the reception end?

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Default Highly Shielded Audio Cable

On Sun, 9 Mar 2014, Ralph D. wrote:

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.

Just use coax. Even something small like RG174 likely has better
shielding than many audio cables.

Of course, if there is a real issue here, little stereo plugs end up
leaving an unshielded area for the RF to get in. Changing to something
else would complete the shield. I know I'd use BNC connectors for audio
connectors if that pile of 200 male connectors I found on the sidewalk
had included 200 female BNC connectors as well.

Make sure the output feeding the coax is low impedance, that's not for
feeding the coax, but a high impedance would make it easier for the RF to
be picked up. And terminate at the transmitter end, so that point sees
relatively low impedance.

Make sure the usual low value bypass capacitors are at the input to that
transmitter, so even if there is RF pickup, it is bypassed to ground and
won't be rectified by the input stage. Get some ferrite beads (the tiny
ones, and put them on the lead between the input jack of the trnasmitter
and the first stage, or the traditional method would be an RF choke of
suitable value.

Look in any radio handbook and there should be a section on RF
interference, which would describe how to keep RF out of the first stage
of an audio amplifier.

Michael






I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!












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Default Highly Shielded Audio Cable

On 3/10/2014 7:11 AM, Phil Allison wrote:
"Ralph Dope"

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.



** I have a sense of "deja vu" about this question ?

Is the signal stereo or mono ?

A 20 foot long 3.5mm two core cable is not gonna be easy to find at all let
alone with different qualities.

BTW:

Do you REALLY have a problem or are you just imagining one ?

How about some details ?

The solution may NOT be what you have guessed it to be.



.... Phil




Hack a long HDMI cable.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
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On 03/10/2014 09:56 AM, Cydrome Leader wrote:
In sci.electronics.repair Ralph D. wrote:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.


get some electrical conduit.


There should not be a lot of RF in the radio room, compared to near the
antennas. Do all the other stations use EMT for audio? It really isn't
necessary. You can probably use unshielded twisted pair if you know what
you're doing. The Phone Company doesn't use shielded cable for baseband
audio.
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On Sunday, March 9, 2014 11:30:08 PM UTC-4, Ralph D. wrote:
Hi,



I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).


Hmm, What kind of interference are you seeing? (can you turn things off and make it go away?) To get rid of electro-static pick-up (display screeens flourescent lights...) get a cable with both braid and a almuinized mylar sheild.
(Driving the cable with a low impedance source should help too.)

60 Hz, magnetic interference is darn hard to shield against (In my limited experience.) Your best bet there is to keep a good distance between transfomeres and the cable.

George H.

Any good suggestions would be appreciated.





Thanks!


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On Tue, 11 Mar 2014, wrote:

On Sunday, March 9, 2014 11:30:08 PM UTC-4, Ralph D. wrote:
Hi,



I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).


Hmm, What kind of interference are you seeing? (can you turn things off
and make it go away?) To get rid of electro-static pick-up (display
screeens flourescent lights...) get a cable with both braid and a
almuinized mylar sheild. (Driving the cable with a low impedance source
should help too.)

That's the question most of us missed. I could have sworn he said "rf
interference", but when I looked back after posting, realized he hadn't
indicated any specific bit of interference.

Michael

60 Hz, magnetic interference is darn hard to shield against (In my limited experience.) Your best bet there is to keep a good distance between transfomeres and the cable.

George H.

Any good suggestions would be appreciated.





Thanks!



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On Tue, 11 Mar 2014 20:02:49 -0700, Michael Black wrote:

...snip...


That's the question most of us missed. I could have sworn he said "rf
interference", but when I looked back after posting, realized he hadn't
indicated any specific bit of interference.

...snip....


I assumed stuff like nearby motor drivers, or worse, from those new solid
state ballasts. The cheap ones can get VERY energetic. and coupling
magnetic into audio is not an easy item to stop.

People are so used to 'shielding' with electrostatic shields and lowering
the impedance to reduce high impedance interference, that they are
completely caught off guard when confronted with low impedance noise
sources, like magnetic field. May have noticed that lowering the impedance
makes little difference.

Sometimes, high impedance noise gets 'converted' somewhere to a low
impedance source which is really mindboggling, since you recognize the
noise and expect it to be coming from high impedance.

Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE
spectrum! DC to GHz, 10GHz if you can do it. That includes termination
circuitry, Tx/Rx, and high quality cabling with very symmetrical conductor
placement and spacings within that cable. That is, if you're goal is 120
dBV, or better 140dBV, down noise floors you had better pay attention to
everything.






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On 03/12/2014 07:58 AM, RobertMacy wrote:
On Tue, 11 Mar 2014 20:02:49 -0700, Michael Black wrote:

...snip...

That's the question most of us missed. I could have sworn he said "rf
interference", but when I looked back after posting, realized he
hadn't indicated any specific bit of interference.

...snip....


I assumed stuff like nearby motor drivers, or worse, from those new
solid state ballasts. The cheap ones can get VERY energetic. and
coupling magnetic into audio is not an easy item to stop.

People are so used to 'shielding' with electrostatic shields and
lowering the impedance to reduce high impedance interference, that they
are completely caught off guard when confronted with low impedance noise
sources, like magnetic field. May have noticed that lowering the
impedance makes little difference.

Sometimes, high impedance noise gets 'converted' somewhere to a low
impedance source which is really mindboggling, since you recognize the
noise and expect it to be coming from high impedance.

Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE
spectrum! DC to GHz, 10GHz if you can do it. That includes termination
circuitry, Tx/Rx, and high quality cabling with very symmetrical
conductor placement and spacings within that cable. That is, if you're
goal is 120 dBV, or better 140dBV, down noise floors you had better pay
attention to everything.


These are pretty darn close to what you need, as long as they are true
balanced. This will put a face on it, any way.

http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml
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"RobertMacy" wrote in message newsp.xcl6jxtm2cx0wh@ajm...

Best way,...balanced pair, shielded. And I MEAN balanced over
the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That
includes termination circuitry, Tx/Rx, and high quality cabling
with very symmetrical conductor placement and spacings within
that cable. That is, if you're goal is 120 dBV, or better 140dBV,
down noise floors you had better pay attention to everything.


It's unfortunate that the OP seems limited to 3.5mm connections. There are AR
cables (Master Series) that have a separate shield, grounded at the receiving
end, with identical wires (not the shield) carrying the signal. There is also
a ferrite choke. I use these in my system.

http://www.amazon.com/Acoustic-Resea...+master+series

They used to be fairly cheap, but have gotten pricey again. (Of course, the
price is still rather lower than "audiophile" cables with the same features.)



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On 03/12/2014 07:58 AM, RobertMacy wrote:
On Tue, 11 Mar 2014 20:02:49 -0700, Michael Black wrote:

...snip...

That's the question most of us missed. I could have sworn he said "rf
interference", but when I looked back after posting, realized he
hadn't indicated any specific bit of interference.

...snip....


I assumed stuff like nearby motor drivers, or worse, from those new
solid state ballasts. The cheap ones can get VERY energetic. and
coupling magnetic into audio is not an easy item to stop.

People are so used to 'shielding' with electrostatic shields and
lowering the impedance to reduce high impedance interference, that they
are completely caught off guard when confronted with low impedance noise
sources, like magnetic field. May have noticed that lowering the
impedance makes little difference.

Sometimes, high impedance noise gets 'converted' somewhere to a low
impedance source which is really mindboggling, since you recognize the
noise and expect it to be coming from high impedance.

Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE
spectrum! DC to GHz, 10GHz if you can do it. That includes termination
circuitry, Tx/Rx, and high quality cabling with very symmetrical
conductor placement and spacings within that cable. That is, if you're
goal is 120 dBV, or better 140dBV, down noise floors you had better pay
attention to everything.





http://muxlab.com/wp-content/uploads...i-Fi_Balun.pdf
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On 03/12/2014 08:10 AM, William Sommerwerck wrote:
"RobertMacy" wrote in message newsp.xcl6jxtm2cx0wh@ajm...

Best way,...balanced pair, shielded. And I MEAN balanced over
the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That
includes termination circuitry, Tx/Rx, and high quality cabling
with very symmetrical conductor placement and spacings within
that cable. That is, if you're goal is 120 dBV, or better 140dBV,
down noise floors you had better pay attention to everything.


It's unfortunate that the OP seems limited to 3.5mm connections. There
are AR cables (Master Series) that have a separate shield, grounded at
the receiving end, with identical wires (not the shield) carrying the
signal. There is also a ferrite choke. I use these in my system.

http://www.amazon.com/Acoustic-Resea...+master+series


They used to be fairly cheap, but have gotten pricey again. (Of course,
the price is still rather lower than "audiophile" cables with the same
features.)

That is pure audio snake oil. If you are dealing with induced magnetic
fields (hum) you need a competent differential input and balanced lines.
The copper part of the phone company is not shielded. Even the part that
carries high fidelity audio for industry is not shielded.

Big clunky interfaces like that are usually very reactive and do affect
the sound...badly. Try Hosa brand. Spend the difference on better speakers.

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"dave" wrote in message
news
That is pure audio snake oil.


My point was that the AR cables had features designed for good shielding. I
never directly claimed that they sounded better. Indeed, my experience has
been that expensive cables don't sound better than the cheap ones that come
"in the box".



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On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.


My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


And I pointed out as someone else did earlier it is not primarily a
matter of shielding.
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On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.


My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


I use the DAC in my home theater receiver for all the audio, which comes
in via S/Pdif. DTS multichannel audio is as exotic as it gets. Hosa
cables are good and cheap. I am just a customer.
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On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.


My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


Here we go. 3.5mm TRS male.

http://www.markertek.com/CATV-Headen...c/500030.xhtml
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dave wrote:

The Phone Company doesn't use shielded cable for baseband audio.



No, but they use twisted pair and they can still pick up a lot of RF.
I've seen over 5 volts of RF on phone lines at AM radio stations that
were wired with 'station wire' instead of twisted pair. The radio
station audio was louder than either party on the line could talk. The
fix was to rip out everything, run 25 pair twisted cable to localized
terminals and use short runs to the phones. There was still some common
mode RF, but at least the lines were usable since it no longer caused
the volume limiter to go into continuous conduction.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.
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dave wrote:


These are pretty darn close to what you need, as long as they are true
balanced. This will put a face on it, any way.

http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml



75 Ohm unbalanced to 110 Ohm, balanced, twisted pair? The fact that he
is using unbalanced audio implies 5K ohm or higher impedance.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.


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On Thu, 13 Mar 2014, Michael A. Terrell wrote:


dave wrote:

The Phone Company doesn't use shielded cable for baseband audio.



No, but they use twisted pair and they can still pick up a lot of RF.
I've seen over 5 volts of RF on phone lines at AM radio stations that
were wired with 'station wire' instead of twisted pair. The radio
station audio was louder than either party on the line could talk. The
fix was to rip out everything, run 25 pair twisted cable to localized
terminals and use short runs to the phones. There was still some common
mode RF, but at least the lines were usable since it no longer caused
the volume limiter to go into continuous conduction.

Yes, and even in the days of the no real electronics in the phones, there
were tips in the books about keeping RF out of the phones.

The issue becomes more significant when all the phones are made of
electronics, and there's a lot more that can act ad diodes to detect the
signals.

Michael

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Ralph D. udtrykte præcist:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy schedule)
but would be OK with ordering from one of the Ham sites if turnaround time is
very good. I could not get a good search parameter on Amazon that didn't turn
up thousands of hits that I just don't have time to sift through right now.

Any good cable with known good isolation would be good. I have ferrite chokes
I can use, but would prefer a cable of suitable quality that did not need
them (current cable is getting interference even with them as this is not
just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


You could go digital/optical with a analog-toslink-analog combo.

There is a combination at the bottom of the ad he
http://amzn.com/B005F20756

It claims only 18 feet, that could be close enough to your approx 20ft,
when there are analog cables in either end.

But I haven't seen an 18ft toslink cable...

There must transmitters which are more powerful, if you need a longer
range.

Leif

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beslutning at undlade det.


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"Leif Neland" wrote in message ...

But I haven't seen an 18ft TosLink cable...


There are couplers.
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On 03/12/2014 10:20 PM, Michael A. Terrell wrote:

dave wrote:


These are pretty darn close to what you need, as long as they are true
balanced. This will put a face on it, any way.

http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml



75 Ohm unbalanced to 110 Ohm, balanced, twisted pair? The fact that he
is using unbalanced audio implies 5K ohm or higher impedance.


Baseband Video is always 75 Ohms unbalanced 1VAC p/p. 110 Ohms is a
standard for digital audio. The fact the device is a BalUn means the
unbalanced audio (and video) is transformed for the balanced
transmission line (and back again after). The video will be a couple
10ths low but the first DA it hits will fix that, otherwise most devices
will AGC it to where it needs to be. As long as the group delay isn't
hideous it'll work for SDTV. There are audio only devices that is the
application we need here.

PS I'm surprised Ma Bell didn't try to sell you a bunch of 111C coils
and active official interface devices.
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On Wed, 12 Mar 2014 23:00:33 -0700, Michael Black wrote:

On Thu, 13 Mar 2014, Michael A. Terrell wrote:


dave wrote:

The Phone Company doesn't use shielded cable for baseband audio.



No, but they use twisted pair and they can still pick up a lot of RF.
I've seen over 5 volts of RF on phone lines at AM radio stations that
were wired with 'station wire' instead of twisted pair. The radio
station audio was louder than either party on the line could talk. The
fix was to rip out everything, run 25 pair twisted cable to localized
terminals and use short runs to the phones. There was still some common
mode RF, but at least the lines were usable since it no longer caused
the volume limiter to go into continuous conduction.

Yes, and even in the days of the no real electronics in the phones,
there were tips in the books about keeping RF out of the phones.

The issue becomes more significant when all the phones are made of
electronics, and there's a lot more that can act ad diodes to detect the
signals.

Michael


AND! the designers usually violate concept of exactly what 'balanced' line
means, then the telephone's own protection system will rectify the AM
signals.

Most radio stations will supply little pigtails to place between your
phone and the line that pretty much drops that RF, for free, as a good
neighbor act.

In one doctor's office sitting by the relatively low powered 10kW AM
towers [Jeff will know where this is, driving south along highway 1 to
your left, just south of Santa Cruz] had between 1V/m upwards to 3V/m and
in some places concentrated to over 7V/m and the station came in louder
than conversations. Now,..extrapolate that to EMP at 20kV to 50kV/m and
you can see why nobody wants missiles AND nuclear capability in the same
hands.


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On 3/13/2014 8:26 AM, William Sommerwerck wrote:
"Leif Neland" wrote in message
...
But I haven't seen an 18ft TosLink cable...


There are couplers.


Monoprice offers this 25 foot Toslink cable for under $5, as well as
longer ones out to 50 foot length.

They work beautifully for the applications I have tried, including the
connection of an AppleTV audio output to a distant A/V receiver in
another room.

http://www.monoprice.com/Product?c_i...seq=1&format=2



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dave wrote:

On 03/12/2014 10:20 PM, Michael A. Terrell wrote:

dave wrote:


These are pretty darn close to what you need, as long as they are true
balanced. This will put a face on it, any way.

http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml



75 Ohm unbalanced to 110 Ohm, balanced, twisted pair? The fact that he
is using unbalanced audio implies 5K ohm or higher impedance.


Baseband Video is always 75 Ohms unbalanced 1VAC p/p.


Yawn. Actually, it's 1.4 volts, because the sync is .4 volts below
the video.

110 Ohms is a
standard for digital audio. The fact the device is a BalUn means the
unbalanced audio (and video) is transformed for the balanced
transmission line (and back again after). The video will be a couple
10ths low but the first DA it hits will fix that, otherwise most devices
will AGC it to where it needs to be. As long as the group delay isn't
hideous it'll work for SDTV. There are audio only devices that is the
application we need here.

PS I'm surprised Ma Bell didn't try to sell you a bunch of 111C coils
and active official interface devices.



'Ma Bell' didn't own the telephone hardware on that Army base. In
fact, they didn't own the White Alice' microwave network that provided
the long distance phone service for a large part of Alaska.


Test some of those cheap video baluns with audio, then tell us the -3
dB points. You keep forgetting that I built Telemetry & video equipment
that you'll never see, and to standards that you can't come close to.
Long before digital TV, my video hardware was flat to 40 MHz. That
included diversity reception, and video combiners that would provide a
solid video signal from multiple fading signals.


--
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have a DD214, and a honorable discharge.
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On Wed, 12 Mar 2014 11:01:01 -0700, dave wrote:

On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.


My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


And I pointed out as someone else did earlier it is not primarily a
matter of shielding.


And i will point out that in OP's case, it is a cabling issue if not
exactly a shielding issue, rather than any other issue.

?-)
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On 03/14/2014 04:58 AM, josephkk wrote:
On Wed, 12 Mar 2014 11:01:01 -0700, dave wrote:

On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.

My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


And I pointed out as someone else did earlier it is not primarily a
matter of shielding.


And i will point out that in OP's case, it is a cabling issue if not
exactly a shielding issue, rather than any other issue.

?-)


The shield can make things worse sometimes.
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"dave" wrote in message
m...
On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.


My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


Here we go. 3.5mm TRS male.

http://www.markertek.com/CATV-Headen...c/500030.xhtml



!!!

Cat5 (e & 6 as well) is something I have a *lot* of. Is there any advantage
to 5e as opposed to 5 for this application? I'd rather hang on to my 6 & 5e
if I could.

How about these adapters. I know they may not have the same quality, but for
2 for $15US it might make it worth taking a shot... not much lost if it
doesn't work:

http://www.amazon.com/3-5mm-To-Audio...gy_misc_text_z













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On 03/16/2014 09:50 AM, Ralph D. wrote:
"dave" wrote in message
m...
On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message
news
That is pure audio snake oil.

My point was that the AR cables had features designed for good
shielding. I never directly claimed that they sounded better. Indeed, my
experience has been that expensive cables don't sound better than the
cheap ones that come "in the box".


Here we go. 3.5mm TRS male.

http://www.markertek.com/CATV-Headen...c/500030.xhtml



!!!

Cat5 (e & 6 as well) is something I have a *lot* of. Is there any advantage
to 5e as opposed to 5 for this application? I'd rather hang on to my 6 & 5e
if I could.

How about these adapters. I know they may not have the same quality, but for
2 for $15US it might make it worth taking a shot... not much lost if it
doesn't work:

http://www.amazon.com/3-5mm-To-Audio...gy_misc_text_z



They may or not work depending on the quality of the transformers. Look
up "CMRR", "differential input"

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"Ralph D." wrote in message
...
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time
to sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did
not need them (current cable is getting interference even with them as
this is not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!


Thanks to everyone for their input. I guess the discussion has about worn
itself out.

After reading what was posted in both groups, I have decided to try this
option first, as I have cable on hand and it would be great if it resolved
for cheap :-)


http://www.amazon.com/Headphone-Jack...5mm+Balun+Cat5



Hopefully I'll have a positive follow-up.


Thanks again.












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in my very hard to get this.

http://belajarteknolgi.com

Pada Senin, 10 Maret 2014 10:30:08 UTC+7, Ralph D. menulis:
Hi,



I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded

to connect my audio source to a transmitter across a room. This cable passes

many sources of interference, so the shielding is critical.



I would prefer to get it from Amazon so as to get it quick with Prime

(incredibly narrow window of free-time during a currently very busy

schedule) but would be OK with ordering from one of the Ham sites if

turnaround time is very good. I could not get a good search parameter on

Amazon that didn't turn up thousands of hits that I just don't have time to

sift through right now.



Any good cable with known good isolation would be good. I have ferrite

chokes I can use, but would prefer a cable of suitable quality that did not

need them (current cable is getting interference even with them as this is

not just run-of-the-mill 60cycle stuff).



Any good suggestions would be appreciated.





Thanks!


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On Monday, March 10, 2014 8:24:12 AM UTC-7, D. Peter Maus wrote:
On 3/9/14 23:49 , isw wrote:

In article ,


"Ralph D." wrote:


I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.


A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.


Yep, this is the best solution: it takes transformers (or active-circuitry equivalents)
though, so it might be a tad hard to implement. The wiring for this kind of thing
is widely used for microphones (microphone cable and microphone connectors
solves the cable-purchase part of the problem).

I'm not sure where to buy, but searching on 'audio balun' seems appropriate.
The word 'balun' indicates a balanced-to-unbalanced transformer (and you'll need two).
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